Severe Weather Potential Wednesday

Today has turned out to be a much more active severe weather day than anticipated, with the SPC just putting out a slight risk for the black hills and a severe weather watch which includes Wall, SD. The severe threat looks greatest to the west of Wall, but we should see some more rain tonight as the storms roll off of the hills as a nocturnal MCS. I think we will see a few hailers in the black hills and just south of the black hills today, much as has occurred over the last few weeks. I do not think we have the wind energy to support a high wind event in the area, and the tornado threat isn't high. However, good backing of the winds supports rotating storms...which could produce a tornado if everything comes together for a particular cell.

For tomorrow:

This looks like the much greater severe weather threat day for South Dakota and North Dakota. A decent 'cool' front (as the NWS calls it) will push through the Dakotas, brought about by a low pressure system moving through southern Canada near the apex of an upper level ridge. Ahead of this front will be great southerly flow (not southeasterly however) pumping in abundant moisture. In fact, dewpoint temperatures reach 65F all the way into southern Canada. The GFS and NAM are in agreement about the placement of this front, which should pass through the western Dakotas in the evening. This frontal boundary, and slight vorticity advection in North Dakota, should initiate storms as the CIN degrades later in the afternoon or early evening. A lot of the storm initiation points will depend on the nocturnal MCSs from tonight which may still be lingering over the Dakotas. If the cloud deck stays around, this severe threat could be lessened as heating wont be as intense. However, the models are saying that these clouds should clear out enough for additional afternoon/evening storms.

The map above gives you a great indication of what the frontal boundary looks like tomorrow evening. You can see the sharp dewpoint drop in North Dakota, which is just north of the 200/300 mb jet max which traverses through the ND/SD border region. Like I said earlier, PVA will be greatest in North Dakota, and a theta-e ridge should build into the area in the afternoon. CAPE of 2000 J/kg, after the loss of CIN as the frontal boundary approaches, should be sufficient (obviously) to support storms which should go severe quickly. I think the greatest threat region for hail and wind will be from the SD/ND border to Canada (and likely into Canada as well). Helicity should be in the range of 50-150 m2/s2 just ahead. of the storms. If this helicity is ingested into a storm, a quick tornado spin up could be possible. A secondary maximum of heavy rainfall, and possible severe weather, could occur along the primary theta-e ridge along the SD/NE border. I think there will be heavy rain in this region as CAPE could approach 3000 J/kg and CIN is forecast to be zero, and it will likely swipe away the greater threat of severe weather in SD itself robbing any storm that does develop in SD of its inflow moisture.

So, in conclusion, I see two areas of interest, western to central ND and the SD/NE border into NE from the west to the central region. Heavy rain will be more likely in the southern area, with severe weather more likely in the north. I expect 30% SPC threat for hail in ND, and possibly wind. 5% tornado in central ND as well, but I do not think we will see many tomorrow. No moderate risk.

Quick Observations

Well, just as predicted, the temperatures rose for a few days into the upper 90s (96F,97F,and 96F) only to fall right back down to the lower 80s (82F, and 82F). So, this unusual pattern continues. However, this looks to be changing.

Little indication of strong frontal boundaries, such as the one that came through three days ago, are shown in the latest GFS model, which is reasonable for this time of year. The model predicts a decent ridge to build over the western US, which again is reasonable this time of year. This brings in ~ 27-30C 850 mb temps for next week. If this holds up, temperatures could be in the upper 90s for a good 5-7 days next week. As for this week, 850 temps are a bit cooler and should only support lower 90s, which is still in line with my forecast of 85-95F after this brief cool spell. The Badlands heat is finally arriving.

However, where are those 100F degree temperatures? Not seeing that trend quite yet. Will have to watch the models and see if things change, but only one day is forecast in the 8-16 day period in which 850 mb temps reach 30C (the cut off for possible 100F degree heat).

Just to note the European agrees with the low 90F temps for the next week, but is not quite as bullish on the warmer temperatures the week after. It does show the building ridge early, but then shows a trough beginning to dig into the NW US on Day 10. I think the model might be a bit too strong with that potent of a trough, but we will have to watch the trends. I will update in a few days as to what seems to be occurring.

As for the Severe Weather the last few days:

A nasty line of severe storms came through last night, producing wide spread 60-70 mph wind gusts, 3/4-1 inch hail, and heavy rainfall. The worst storm travelled adjacent to I-90, just to the north, and pushed out a very strong outflow boundary to its south. This outflow, and the storm itself, produced much of the severe wind gusts reported in the area. The outflow initiated further storms to the south of the Wall area which traversed into the Badlands. A great lightning show was produced by every convective cell last night. And on top of this, further development occurred behind these clusters, likely as the cold pool began to moderate slightly, and brought hail to Wall (1/2 inch) in the middle of the night. Definitely woke my wife and I up!

A report from the night before in Custer, SD was of hail covering the city to the point that they had to close roads because they were impassable!

And on Wednesday, my wife and I drove to Murdo and Chamberlain to chase a few severe storms. Nothing too impressive was seen, but I have included some of the best pictures. The one report we saw for the storm we were chasing was of large hail denting cars and busting windows in Presho, SD. Otherwise, we watched a storm to the north of our position, which appeared to have a ragged wall cloud, drop its core and push out a quick shelf cloud which rolled up into the sky. Add on top of that a nice stadium effect frontal edge and blue hail core, and the storm was worth chasing. Quickly after that occurred, however, a second storm interacted with the cell and ruined our view ending the chase day. We drove back to Wall only to be impacted by a storm with packed 70 mph winds just to our north. Definitely a fun day.

Storm which produced the damage in Presho, SD.

Ragged wall cloud and impressive storm structure from storm near Pierre, SD.

Wall cloud degrading, and pushing out towards right.

Weather Trends for Philip-Wall-Badlands Region

What is up with this weather?! Crazy stuff going on here in southwestern South Dakota, and the entire northern plains. Severe weather, including tornado outbreaks in Minnesota and North Dakota over the last two weeks, massive flooding from Indiana to South Dakota, and now the cool temperatures. The question is, should we expect things to start to change and finally go into a hot pattern, or will this 'cool' weather continue?

The answer:

Expect the odd weather to continue. Just like a few days ago, another warm spell will take over southwest South Dakota over the next 3 days, likely peaking highs into the upper 90s in some parts by Tuesday. However, this hot weather will not last long, as another cold front will push through, shown by both the NAM and GFS as on Tuesday night/Wed, bringing 850 mb temps back down from near 30C to 13-15C! Again, another cool spell is in store for the Badlands region! If the 13-15C 850mb temps verify, the high could be as low as 69-73F! I don't think we will see temperatures quite that low, but cool weather in the lower 80s looks possible. The European model isn't quite as bullish with the cool weather, and we could be seeing a model bias in the GFS of bringing in a cold front that is too strong, so we will have to wait and see. However, considering the average high in Philip, SD should be 87F, this will feel very nice. On top of that, last year we would already have experienced four 100F, and several 99F, degree days at this point in the year! This year, the highest temperatures have been 97F, 90F, and 90F. Much, much cooler!

But how will the weather trend over the next 2 weeks?

The weather looks to stay much the same as we have seen over the last month. The GFS and European don't seem to be trending towards hot 100F degree days just yet. It does seem inevitable that one of these hot days is coming, but with no 30C 850 mb temps forecasted over southwestern South Dakota for the next 384 hours by the GFS, and the European not showing it for the next week, it doesn't look like we will hit 100F anytime soon. (Baring the slight chance we hit it on Tuesday this week, with 850 mb temps forecasted to be up to 30C, supportive of 100F). I think we will have highs ranging from 85-95 over the next two weeks. Hot, but not too hot.

Verification for Philip, SD

Sunday July 6th:
NWS Forecast: 89F
My Forecast: 87F
Actual High: 89F
Difference: 2 degrees

Monday, July 7th morning low:
NWS: 64F
ME: 65F
Actual: 63F
Difference: 2 degrees

Monday, July 7th high:
NWS: 89F
ME: 80F
Actual: 86F
Difference: 6 degrees

NWS Error: 4 degrees
My Error: 10 degrees

What happened?

I ignored the GFS 850 mb temperatures and got burned. Lesson: When the GFS 850 mb temps are warmer than the NAM, the high is likely to go warmer than the 850 mb temps forecast by the NAM.

Bertha Strengthens to a Category 3 Hurricane

Bertha has gone through a major increase in strength today. The storm moved into warmer sea surface temperature waters (27C-28C) and moderate to low wind shear (15-20 knots) and quickly strengthened from the first hurricane of the season to a major hurricane in 12 hours. But here is the good news, it looks like this system is headed out to sea.

Only a few models are currently predicting that this system will move further westward without a northerly component. A strong ridge is above the system, and will likely continue to push the storm to the northwest or westnorthwest over the next day or two. However, a frontal boundary, and the system itself, will beat on this ridge, causing it to weaken, allowing the system to move off to the north and then out to sea, which most of the models agree with. The GFDL and HWRF, the most trusted and specifically designed hurricane models, want to take Bertha north and off to the east of Bermuda. Just 12 hours ago the National Hurricane Center was thinking this storm would travel between Bermuda and the United States, but now even they are trending towards to eastern solution. I agree with them that this storm is going to be a 'fish' as many people call them, a storm that does not impact a large land mass.

The rapid intensification has occured as the wall feature cleared up in the last 6 hours, and new wall cycles often last from 18-36 hours. This means the system still has plenty of time to strengthen in the condusive environment for the next 24-36 hours. I expect we will likely see a high end category 3, or low end category 4 hurricane before the storm reaches its max intensity.

Bertha is a record breaking storm, developing the furthest east in July as a depression, tropical storm, and hurricane. It is also the furthest east developing major hurricane in July. However, as you might be thinking, the strengthening today does not even rival past hurricanes, such as Wilma and Felix. Hopefully Bertha is not a sign of what is to come this season.

Buffalo, Wyoming Severe Weather Threat

Today is looking like a good chance of severe weather in NW WY and SW MT. Decent CAPE (500-1500 J/kg), helicity (100-150), dewpoints in the mid-50s, and steep low level lapse rates look to be in place in NW WY this afternoon. A shortwave trough will push into the area around 2000Z or 2 pm (currently 1615Z, 1015 am). This should trigger storm formation over the higher terrain. These storms will quickly strengthen into supercell structures, which the SPC says will likely produce a tornado or two.

Looking at the current model runs, it looks like the earliest thunderstorm development should occur over the mountains just west of Buffalo, WY and then traverse out into the lower hills and plains in NW WY. This is the region that will lose the CIN earliest, has high CAPE, and decent helicity. Add in shear vectors of 30-35 knots, and spin should be likely with these storms. I believe this will be the location of the possible first tornadic storm.

I would say watch carefully this afternoon, except radar coverage in this area is lacking, and you probably wont be able to see much of the storm on radar. I expect a few tornado warnings (1-3) this afternoon.


The quick forecast for today:

Today: High 87F, partly cloudy skies with showers/t-storms possible in the evening. No measureable precip predicted. (NWS: 89F)

Tonight: Low 65F, cloudy skies with showers/t-storms likely. Severe weather not anticipated. Precipitation: 0.08 inches (NWS: 64F)

Tomorrow: High 80F, cloudy skies in the morning with showers/T-storms possible in the afternoon. Severe hail and wind possible. Precipitation: 0.20 inches (NWS: 89F)

Verification for Philip, SD

Forecast for Saturday, July 5th:
NWS Forecast: Fri morning 99F, Sat. morning 96F
My Forecast: Fri morning 96F, Sat. morning 95F
Rainfall forecast: None
Actual High: 90F
Actual Rainfall: None
Temperature Difference: 5 degrees

Why the temp error? Cloudiness in the morning held back the high before the cold front moved through. Once the cold front did move through Philip it cleared up, but 850 mb temps had dropped considerably, not allowing for the high to break 90F. It was expected that 850 mb temps would drop, but not as substantially as occured, thus the high was not able to get back up into the mid-90s. Pine Ridge, SD (40 miles south) reached 94F yesterday.

Forecast for Sunday morning low:
NWS Forecast: 63F
My Forecast: 63F
Rainfall forecast: 0.05 inches
Actual low: 65F
Actual Precip: 0.04 inches
Temperature Difference: 2 degrees

My Total Difference: 7 degrees
NWS Difference: 8 degrees

Weather Prediction

Currently:

10 am:
Philip, SD:
Temp: 73F, Dewpoint: 66F
Wind: SW 6 mph
Clear Skies

Frontal boundary already 1/3 of the way through most of ND, lagging back to NE/SD/WY border location. The boundary is a clear wind shift, but temperatures and dewpoints do not drop substantially behind it. Actually, currently the temperatures are warmest behind the front in SW Montana (mid-80s). The current satellite shows high level, and a few mid level, clouds out ahead of the boundary in western SD, ND, and into WY/NE. These high level clouds should keep temperatures down a bit today as compared to the previous forecast. Definitely lower than the 99F the NWS was forecasting.

Today:

Cloudiness, which wasn't forecasted well by the models yesterday, looks to help keep temperatures down. There isn't a single 80F temperature in all of SD or ND, which is similar to this time yesterday. At 10 am yesterday Philip was 76F, 3 degrees warmer. However, today 850 mb temperatures are much warmer, and yesterday had 3 hours of flatline temperatures. So, if a 2 degree warming for the three hours had occur, 94F looks easy. 850 mb temps are highest at 2/3 pm before the boundary comes through Philip at 29C, or supportive of 37C/98F. This is down from the possible 103F from yesterday. With the cloudiness, cooler starting temperature, and frontal boundary moving through at 2 pm ish, the high temperature should have difficulty maxing out at 98F, so will go with a few degrees cooler and 95F. Still a very hot day. If any convection develops with the front, we could see even cooler temperatures, closer to 90, if an anvil or storm travels directly over Philip. There shouldn't be much rainfall in Philip today as the CIN will stay up, reducing the chance of a thunderstorm, but it could still happen. 20% chance. (My forecast yesterday: 96F; NWS: yesterday: 99F, today: 96F)

Tonight:

This is the fun forecast, with some models predicting rainfall, and some not. The SPC seems confident in a few thunderstorms developing in the WY mountains and Black Hills into the evening. The storms could produce a nocturnal MCS and travel out into the plains within the flow aloft. These storms look to be initiated by the higher terrain and a Theta-e axis, decent CAPE (500-1000 J/kg), and eroding CIN by 00Z. Dewpoints will be 50-55F in WY to 65F in central SD. These dewpoint temperatures should slowly decrease through the night in the Philip area, with any rain dropping the temperature quickly towards the dewpoint, if not a bit lower as the dewpoint temperature continues its drop behind the frontal boundary. Rainfall looks to be fairly likely south of Philip, but not to the north. In other words, Philip will be right on the boundary between precipitation and none. Thus, a 40% chance of precip tonight, and 0.05 inches forecasted. With a northerly wind at 5-10 mph, dewpoints slowly dropping to near 60F by morning (per MOS), and ETA/GFS MOS forecasting 65/64F respectively, it looks like the low should be in the lower to mid-60s. I will go with 63F tonight, consistent with the lower end trend throughout the last two weeks. (NWS: 63F)

Tomorrow:
The SPC has put out another slight risk chance of severe weather, but mainly for NW WY for hail. Dewpoints will stay up in NW WY, but fall sharply in SW MT. This will lead to a little dryline in the WY/MT border region. CAPE will increase to 500 J/kg with an uncapped environment in NW WY. Add in terrain forcing and a few storms should develop. Helicity values will be between 50-150, supportive of some twisting in the atmosphere, and possible super cell structures. However, the Philip area will be capped and have no CAPE, thus reducing the possibilities that the storms should hold together into the evening and travel out into the plains before nightfall. Thus, Philip only really has a minimal chance of an evening storm outside of lingering showers in the morning from the nocturnal MCS. I say no rain. As for temperatures, some lingering high level cirrus should travel into the area as convection develops over the higher terrain to the west, but other than this, temperatures should approach 850 mb temp (23C) potential, which is 31C/88F. ETA/GFS MOS say 92/88F, and NAM RAW is 91F. With a little bit of cloud, it might hold the temperature down a degree, so 87F. (NWS: 92F)

Verification for Philip, SD

Forecast For Friday, July 4th:
NWS Friday morning forecast: 90F then changed to 92F
My Friday morning forecast: 88F
Rainfall: None forecasted
Actual High Temperature: 88F
Actual Rainfall: None
Temperature Difference: Zero Degrees

Forecast For Saturday Morning Low, July 5th:
NWS Forecast: 64F
My Forecast: 61F
Rainfall: None forecasted
Actual Low Temperature: 59F
Actual Rainfall: None
Temperature Difference: Two Degrees

Total: 2 degrees
NWS: 9 degrees

Severe Weather Possibilities

The SPC has placed central SD and ND in a slight risk of severe weather tomorrow. On top of this, a major difference in high temperature forecast for tomorrow in Philip is currently present when comparing The Weather Channel (88F) to The National Weather Service (97F). Add in a 40% chance of rain from TWC and a 20% chance from NWS, there are major differences in the forecast for tomorrow. So, lets look at what the models are telling us.

The forecast for today, by both services, is for highs around 90F with mostly sunny to sunny skies. Thus, the issue does not have to do with weather forecasted for today.

Currently it is 72F at 10 am in Philip, SD with calm winds. However, the flow is generally out of the south throughout the region and will likely increase in Philip as the day progresses. Dewpoints are in the mid-50s to near 60 from Canada through SD.

Taking a quick look at the GFS model to get a general feel of the weather over today and tomorrow, the GFS keeps a southerly flow into the Dakotas through tomorrow mid-day. Near 18Z or 00Z a mid-lat cyclone will move to the east through southern Canada. This will bring a trailing cold front through North/South Dakota somewhere between those hours. This cold front will be the triggering mechanism for any thunderstorms tomorrow. It will also lead to cooler air moving into the region, possibly indicating why TWC and NWS have such differing high temperatures, as the timing could be difficult to pinpoint.

GFS model:

Today the 850 mb temps, under the southerly flow, will peak at 22C this afternoon, supportive of 30C/86F high temperatures, a little cooler than both TWC and NWS. Mixing looks to be minimal with only 4-6 mph winds predicted at the surface. The Philip area will be under NWesterly flow aloft at 200-700 mb, as an upper level ridge slides eastward. The crest of the ridge will move over the Dakotas around 12Z tomorrow as a 500 mb vort max moves through western MT and southern Canada. This vort max looks like it will traverse mostly north of South Dakota, leading to PVA mainly in southern Canada and ND near 18Z. The PVA looks to be lagging behind the surface boundary throughout the frontal passage, reducing the influence it will have on storm initiation. However, with the added convergence from the cold front, and dewpoints in the mid-50s, shower/t-storm development looks possible over ND into SD (and in Canada). I would put the highest risk of rainfall in mid-ND northward.

As for 850 mb temps tomorrow, they increase to 25C by 4 pm, or supportive of 33C/92F. The RAW GFS forecasts a high of 94F. This is much cooler than temperatures forecasted by the NWS. Little moisture is found at 700 mb, which leads to questioning about shower possibilities in the region. However, CAPE will increase to 500-1000 J/kg near 18Z, as the cold front traverses through Philip. CIN will also be high, 200-300 J/kg, no helicity, and LI of -3. In other words, there is a decent amount of instability, but with high CIN, any convection will be unlikely surface based with the LCL over 700 mb and the LFC at 600 mb! Basically, things look caped in the Philip area, and the GFS does not produce any rainfall for SD at all.

As for the NAM:

850 mb temps today: 23C, supportive of 88F. 850 mb temps tomorrow: 30C, supportive of 100F! Already we are seeing a major difference in the models. Add in dewpoints near 60F for Philip, rather than mid-50s for the GFS, and things could be very different tomorrow.

A few things are similar between the models. They both bring the ridge over the area tomorrow afternoon, with a 500 mb vort max traversing through MT/southern Canada into ND, missing SD. It is again lagging behind the cold front. However, a small bit of vorticity is shown over the Black Hills at 18Z, putting a little PVA right over the Wall/Philip area in the heat of the afternoon. Add in that the NAM isn't forecasting the frontal passage until 20Z, this gives the opportunity of storms a bit more possibility.

The RAW NAM is forecasting a high of 103F, which doesn't really scream severe weather. Rather, it screams CAP! Looking at the CAPE forecast by the NAM, it is much higher in the 1500-2000 J/kg range, with CIN dropping to near 30-50 J/kg from 20Z-21Z, just as the front passes but over 100 J/kg every other hour during the day. The LCL/LFC levels are above 700 mb, so elevated convection looks like the most likely possibility, if there is any. Helicity is still low, 0-100 m2/s2, indicating difficulty to have rotating updrafts. Actually, as the CIN decreases, Helicity values drop to 14 m2/s2, decreasing the rotation possibilities.

The 22-km WRF initiates convection in the center of SD/ND and only gives a quick pulse of convection, reducing certainties that severe weather looks likely. Actually, the greater chance of precipitation looks post-frontal as a secondary low develops in CO/WY and brings in shower/tstorm activity in the late evening into the morning hours (nocturnal MCS time!).

So what do I think about the severe weather?

The possibilities look low for the Philip area, but higher to the north in ND. The SPC places a 15% chance of severe weather tomorrow from Philip north to the Canadian border, east to the MN border. I think there will be a few severe storms tomorrow, but they will be short lived in the SD area. If the small vort max in the Black Hills, shown by the NAM, actually exists, there could be a chance of a storm in the Philip region as the front moves through, but it seems a bit fishy and not prudent to jump on such a small vort max. I will go with a 20% chance of storms from the front here in Wall/Philip.

As for the Temperatures:

The ETA MOS is forecasting low 90s today, 98F tomorrow, and the GFS MOS is much the same (low 90s/97F). Considering the large spread in 850 mb temperatures tomorrow, this forecast is very difficult. There are a few things that lead me to lean towards the higher end, the first being the very high 850 mb temps forecasted by the NAM, the second the agreement between the MOS values (and raw GFS of 94F), and the high levels of CIN tomorrow likely holding back storm initiation. RAW NAM has winds out of the south at 10 mph, enough for good mixing. However, the frontal passage is near 2-4pm, and if it does have any cloudiness with it (and the lowering 850 mb temps behind it), temperatures could have a difficult time at peaking at the 103F thought by the RAW NAM and its 850 mb temperatures.

Thus, 88F today (held back by 850 mb temps, not cloudiness) and 96F tomorrow. I think the area will heat up quickly in the morning and try to climb towards the 850 mb temp potential forecast by the NAM, but the frontal passage, and any cloudiness with it, will stop the climb around 2pm. By the time skies clear a bit again the 850 mb temps will be back down 5 C, only supportive of 94F. Lows tonight, under clear skies and 4-5 mph winds, should drop easily. Dewpoint temperatures forecast by the MOS are near 60F, with ETA/GFS MOS forecasting 62F/60F respectively. I don't have a problem with those temperatures, I'll go 61F.

My numbers: 88/61/96

NWS numbers: 90/64/97, then upped to 92/64/99 at 11 am

Verification for Philip, SD

Forecast for Tuesday, July 1st:
NWS Forecast day before and morning of the 1st: 93F/95F
My forecast day before and morning of the 1st: 93F/92F
Forecast Precip: None
Actual High temperature: 93F
Actual Precip: None
Temperature Difference: zero/1 degrees

Forecast for Wed, July 2nd morning low:
NWS Forecast: 63F
My forecast: 62F
Forecast Precip: None (20% chance of nocturnal MCS)
Actual Low: Questionable, was 61F at 8am, then dropped to 58F as rain moved in
Actual Precip: 0.19 from 8 am till 10 am from nocturnal MCS
Temperature Difference: 1 degree or 4 degrees?

Day before forecast for Wed, July 2nd high:
NWS Forecast: 74F, 78F forecast by Wed morning
My Forecast: 74F
My Rainfall forecast: 0.03 inches
Actual High: 74F
Actual Rain: 0.19 inches
Temperature Difference: zero degrees

On this date last year....

On this date last year it was 102F degrees for the high! And tomorrow, 97F!

Amazing what one year will do, but today it looks like we might reach the mid-90s...but tomorrow, the mid-70s! Possibly in the 70s again on Thursday too. I am glad we moved up here this year rather than last year!

Just a little tidbit.

Tuesday, July 1st: 3rd of July Wx Forecast

Yes, I did say the 3rd of July and not the 4th because Mt. Rushmore does their large fireworks display on the 3rd (for some odd reason). If they had picked the 4th, the weather would likely cooperate fully...but as for now, it looks like there might be a chance of showers, and possibly a thunderstorm, into the afternoon on the 3rd. Hopefully they move out by dark and the firework show can go as planned. I have heard it is very good, we Shaina and I will definately be there.

As for the forecast:

Currently:

Philip, SD is located in westerly flow aloft to the surface. Winds are blowing at 13-14 mph at the Philip weather station with a current (10 am) temperature of 80 degrees, up only two from the hour before. Skies are clear in Philip, but here in Wall they are mostly cloudy (which makes me wonder about the Philip report). Visible satellite shows mid-level clouds moving to the east, and higher level clouds traveling a bit more wsw over the area. Clearing could occur over the Wall/Philip area as these clouds continue their eastward movement, but cumulus is forecast to rebuild behind it. Looking at the surface map, a weak dryline/cool front boundary has moved through the area, and might be the trigger for some of the cloudiness. Just to the east winds are out of the south. It might be 80F here, but just to the north in ND its already 89F. Obviously the cloud cover is holding back the temperatures.

Today:

The models have changed a bit, enhancing rainfall over the region as compared to yesterday. Actually, the NAM is forecasting rainfall in SW SD in the next 6 hours, which does not look likely considering the clear skies over that region. I think the NAM was likely seeing the cloudiness over west central SD, over the Wall/Philip region, but no rainfall is seen on the radar besides a small blurp in SW WY. An area of vorticity will traverse over the region this evening, brining the chance of showers tonight, but should keep the area dry today. The vorticity max is associated with a very small shortwave. For today, as a second area of vorticity moves east of the region currently, the cloudiness should wane, resulting in clearing skies by afternoon except for high terrain convection, and likely heating. Considering how easily temperatures got to near 90 in ND, and the possibility of clearing in the afternoon, I still think low 90s are possible. However, 93 might be a stretch. Watch for temperatures to increase slowly through the day with 850 mb temps still 26C. My forecast: 92F. (NWS: 95F)

Tonight:

The shortwave will begin to move into the region, resulting in a chance of thunderstorms during the evening and overnight. Often in these conditions, with a strengthening nocturnal low level jet, storms are able to form over the higher elevations and roll out over the plains. This usually results in storms around 3 in the morning (not to our liking!). It is possible this is one of those days, but it doesn't look too likely with cold air advection starting tonight. This cold air advection is in conjucture with the frontal passage that is occuring currently, but lagging a bit behind in the upper levels. RAW NAM is forecasting 0.03 inches of rain tonight, while the GFS is forecasting none. I think I will stick with no rain tonight for my official numbers, but with a 20% chance. The RAW NAM is still forecasting a low of 69F, which seems way too warm with clearing skies and dewpoints in the 50s for the raw. The ETA/GFS MOS are saying 63F/64F, respectively with dewpoints near 60F for the ETA. I don't see much reason to go against them today, except that the low has been very close to the dewpoint each of the past 4 nights. This would lead me to undercut the guidence and go with 62F instead. (NWS: 63F)

Tomorrow:

A much cooler day in store. The frontal passage will be complete, cold air advection at 850 mb will be underway, and cloudiness will dominate the area (as per the models). 7oo mb moisture will increase in the afternoon, leading to thicker cloud cover and possible rain showers. Under a cold air advection regime, thunderstorms seem less likely, but could still occur down wind of the higher terrain (such as the Black Hills). The possibility of rainfall is enhanced due to vorticity maximums swining through the area and another small shortwave trough at 500 mb. The RAW NAM is spitting out 0.05 inches of rain, mostly in the afternoon, which makes sense. It should be a showery affair, rather than a thunderstorm day. Thursday looks more active to me than tomorrow. That being said, 0.03 inches of rainfall. As for the temperatures, the RAW NAM says temperatures should max out at 80F, ETA/GFS MOS say 78F/80F with dewpoints dropping into the mid- to low-50s. 850 mb temps are 16C, which supports 24C/75F. Considering the cloudiness and 850 temps, it makes sense to definately go below guidence! 74F looks good, definately if there are any sunny periods early. Otherwise, it might be a low 70s day right after highs in the mid 90s! (NWS: 74F)

For Thursday, Fireworks day:

Questionable. Thats all there is to say. The NAM model is forecasting some rainfall in the morning, but lingering it to the afternoon. The festivities at Rushmore begin at 7 am, so rainfall at any time of the day is bad, however if it moves out by the afternoon it should be ok for fireworks. As for the wind, little mixing should be going on due to thick cloud cover through mid-afternoon per the NAM. Still, even if mixing is possible, gusts to 20 looks like the highest will be seen. The GFS is not quite as bullish with the cloud cover, but still shows some throughout the afternoon. Highs look to be similar to Wednesday, in the mid to upper 60s in the hills. So, if the rain holds off, such as the GFS says, it should be a wonderful day for fireworks, maybe even feeling cold. Philip might have highs only near 70F! Wow, and this is July!

Verification for Philip, SD (and comments)

Monday, June 30th:
NWS Forecast: 85F/88F
My Morning forecast from sunday/monday: 92F/88F
Rainfall forecasted: none
Actual High: 88F
Actual Rainfall: none
Difference: 4 or zero degrees

Reason for 4 degree error: I made this forecast before I knew what level (850/700mb) to look at for high temperature maximums. Thus, when I forecasted more correctly with 850mb temps, I forecasted the correct high.

Tuesday, July 1st morning low:
NWS Forecast: 59F
My forecast from Monday morning: 57F
Rainfall forecasted: none
Actual Low: 57F
Actual Rainfall: none
Difference: zero degrees


Note: So far, not including the two highs that I forecasted using the wrong information (gotta learn some how), I have an error of TWO degrees over FIVE temperature periods! Thats impressive. Even if you include the 5 degree error, that would only make 7 degrees over 6 periods, which is still good. National Weather Service: 8 degrees over 6 periods.