Verification for Philip, SD

Sunday June 29th:
NWS forecast: 78F
My morning and day before forecasts: 83F/83F, no rainfall
Actual Temperature: 78F
Difference: 5 degrees
Rainfal: None
Reason for error: Used 700 mb temps and MOS, should have used 850 mb temps

Monday June 30th low temperature:
NWS forecast: 53F
My forecast: 51F, no rainfall
Actual Temperature: 50F
Difference: 1 degree
Rainfall: None

Monday, June 30th: Forecast

Currently:

The western United States are in the middle of an upper level ridge, with the Dakotas in the entrance region, resulting in northerly flow at the 500 hPa level. At 850 hPa, the wind shifts to out of the south with the crest of the ridge already east of the western Dakotas. At the surface the winds match up with the 850 hPa level and are out of the south in the western Dakotas. Currently (10 am) the temperature is 74F, 54Fd, and winds SSE at 13 mph in Philip. Skies are clear throughout the Dakotas.

Today:

Learning from yesterday's fiasco with the high temperature, it is important to look at exactly how high mixing will occur. Yesterday mixing was weak with winds only in the 5-8 mph range. Today, with winds already up to 13 mph, it is likely that there will be better mixing. However, RAW NAM and GFS/ETA MOS show wind speeds should decrease in the afternoon. Mixing looks to reach 780 mb. This again would support using 850 mb temperatures for an indication of the maximum temperature (adding 8C to the 850 mb temperature). In the afternoon the 850 mb temp will be 23C, which results in 31C or 88F for the high temperature today. RAW NAM, and the MOS all agree the high will be 91F today. Considering yesterday was right in line with the 850 mb temp potential with clear skies (like today), even with warm MOS temps, it makes sense to stick with the 850 potential at 88F. (NWS: 88F)

Tonight:

Clear skies, once again. However, this time the dewpoint is forecast to be much warmer, in the mid to upper 50s. The MOS have been very good at forecasting low temperatures, unlike the raw, and show the low at 58/57F, close to the dewpoint temp. The RAW NAM is predicting 61F. I will stick close to the MOS, going with the lower number 57F. Tomorrow night the low temperature will start to get more interesting with clouds in the area. The only issue tonight is a strong nocturnal low level just only 500 meters above the surface. If the atmosphere does not decouple, or de-decouples (ha!) then the low might not reach its potential. However, I think this wont happen. So, 57F. (NWS: 59F)

Tomorrow:

This should be the hottest day of the week, along with the first chance of precipitation. GFS/ETA MOS are both forecasting 97F for the high. The RAW NAM is much the same with 96F for the high. There should be some mid-level clouds and possible thunderstorms over the higher terrain as an upslope flow commences and increased dewpoint temperatures. GFS MOS is a bit cooler at 54F dewpoints, but the ETA MOS says 59F. RAW NAM brings the dewpoint down to 50F in the afternoon. This is likely because of the weak winds and possible weak mixing. Either way, 50F dewpoints look likely. I don't think Philip will see any rain tomorrow, but the clouds from convection off of the hills might reduce afternoon temperatures. 850 mb temps are 27C in the afternoon, or supportive of 35F, which is 95F. With clouds in the picture and a 95F maximum, I will go just below this at 93F. I would be very surprised to see highs in the upper 90s tomorrow, but it could be possible if no clouds move in and the 850 temps are off by a degree C. (NWS: 90F)

Next few days:

Upslope convection should increase over the next 2-3 days. Temperatures, on the other hand should decrease before the strong ridge moves overhead into the weekend. Next week should be very warm in the western ridge.

Tropical Update

Get ready for the 'fun' to begin. All reliable models are forecasting a tropical system to form off of Africa in the next 3 days. Considering the good model agreement, high sea surface temperatures in the region in which the wave will come off of Africa, the strength of the wave currently in Africa, the presence of a surface low already over land, and a low shear environment...development looks likely. My odds have gone up from 30% to 50%. I believe that we will at least have a tropical depression in the next 3-5 days. However, the NHC can sometimes be slow to designate a system out near Africa as they rarely threaten land, so there could be a delay until we see the depression designated if it doesn't strengthen quickly.

On top of this threat, there is now a possibility of a storm in the gulf with the CMC and GFS predicting a system will form off of the Texas coast over the coming weekend. This is the first time I have seen this in the models (the last model run) so it should definately be taken with a grain of salt. Sea surface temperatures should be decent, but other factors are not quite as good with shear forecast to be high. What the models might be picking up on is a cold front that is forecasted to move south over the next few days, and this might enhance convection near the gulf. It is possible we are seeing convective feedback with the GFS...and enhanced tropical development with the CMC which it is known to do. The CMC is the only model forecasting two tropical waves to roll off of Africa and both form storms, which indicates how it can be too aggressive at times in the tropics.

Even with all this said, it should still be a good idea to watch for any tropical signs in the gulf region over the next week.

The Pacific will continue to stay active with two more tropical systems forecasted by the CMC/GFS/European over the next week. I wouldn't be surprised to be on the E storm by this time next week.

Use....

850 hpa temperatures...that is the lesson today with the high only reaching 76. 850 hPa temps were forecast to be 17C, which would support 25C or 77F! Should have went with 77F today and 86F tomorrow.

Verification for Philip, SD

Saturday June 28th:
NWS forecast Saturday morning: 74F
My forecast on Saturday morning: 75F
Actual High temperature: 75F
Difference: Zero
No rainfall



Sunday June 29th morning low:

NWS forecast Saturday morning: 49F
My forecast on Saturday morning: 52F
Actual Low temperature: 51F
Difference: One degree
No rainfall

Sunday: June 29th Synopsis

Current:

The surface/upper level low that produced the strong winds yesterday has moved well east into the great lakes region. The pressure gradient has reduced over the western Dakotas and currently wind have died to around 6 knots. The current temperature in Philip is 68F with a dewpoint of 56F. A highly amplified pattern is currently in place across the United States with a deep trough in the east and a large ridge in the west. The Dakotas are currently in the entrance region of the ridge.

Today:

Clear skies and light winds (5-10 knots) should rule the day as the low pressure system that produced the 30 knot winds yesterday moves well to the east. Wind should stay out of the north until evening, keeping dewpoints down in the lower 50s/upper 40s. In other words, a very comfortable day ahead of us. My original forecast from yesterday was for a high of 83F, which still looks on track. 850 hPa temps have come up slightly from yesterday's model runs, now 17C, with 700 hPa temps to 7C. This should support temperatures into the lower 80s, possibly the mid-80s, so 83F looks good. I wouldn't be surprised to see the temperature spike quickly to near 80 by 1pm and level out for much the rest of the day. I think 3 more degrees is possible with 850 hPa temps increasing through the afternoon. RAW NAM says 81F, ETA MOS 81, and GFS MOS 85, all up from yesterday. (NWS: 78F)

Tonight:

Clear skies and light winds continue. Models are keeping moisture out of the region at least through tomorrow, leading to good radiational cooling as winds are forecast to drop to around 4-5 knots tonight. Such light winds could let the atmosphere decouple, leading to calm winds and even lower low temperatures. With the dewpoint again forecasted to be near 49F in all of the models, lower 50s look likely. The RAW NAM forecasts 59F, ETA/GFS MOS forecast 52F. Considering tonight should be a very simple night for the statistical models, I will trend towards their temperatures rather than the RAW. 49F was the dewpoint last night with winds near 7 knots and the low was 51F. I am thinking thinking it might be the same again tonight. My forecast: 51F. (NWS: 53F)

Tomorrow:

The start of the warm temperatures begins. Wind will change from northerly to southeasterly, bringing in a little more moisture. However, it wont be enough to lead to a chance of showers, and more likely will be clear skies. Would not be surprised to see some clouds over the higher terrain with the upslope flow. However, this increased southerly flow will help lead to the greater chance of storms Tuesday into the rest of the week. The high looks to be above 90F, with 850 temps 22C, 700 hPa temps of 12C. This should support highs of 86F(30C)/96F(36C) respectively. RAW NAM says 88F, ETA MOS 91F, GFS MOS 95F. Again, now knowing what level I should be judging mixing in this region is making it difficult to forecast the high temperature, but I like using the 700 hPa level and dropping a degree or two considering mixing seems to reach 725 hPa at this time (and 850 hPa is easily mixed out). I will go with 92F, but with little confidence. Needless to say, its going to be warm. (NWS: 85F)

2-6 days:

Welcome back thunderstorms! Hopefully we can get something to chase or at least take lightning photos out in the plains. Temperatures will stay warm through Wednesday when a front will move through dropping temperatures back into the 80s. Watch for highs on Tuesday near 95. It could even be warmer just south of Philip. The Badlands will not be a fun place to be on Tuesday.

7-14 days:

A quick look at the models supports yesterday's forecast of warm temperatures and dry conditions. The Badlands summer is about to begin. Some hints at nocturnal MCS development are shown in the GFS, but at this time it will be very difficult to forecast as these are predominantly driven by shortwaves.

TROPICAL UPDATE:

The tropics are very active...on the eastern Pacific side. Currently there are two storms, Boris and Cristina. Both minimal tropical storms as Boris' intense strengthening on satellite did not lead to strengthening in the wind field (per NHC). Cristina was the system I said two days ago had about 24 hours to develop, which is about all it had. It is currently moving over lower sea surface temperatures and will be weakening to a tropical depression soon. Boris still has more time, but maybe only 12-24 hours do strengthen before it too moves over cool sea surface temperatures and dissipates out in the central Pacific.

Further development of a tropical system in the eastern Pacific looks possible in the next few days as many of the models are producing a tropical system moving up the west coast of Mexico towards the Baha. If the system does develop, and travels right up the coast, it could be a major flooding situation for Mexico. Currently the cluster of thunderstorms which could produce this system is south of Guatemala and Honduras. No low level circulation looks evident yet, but with the supportive MJO currently over that region, a low level circulation could develop in the moderate shear, warm sea surface temperature environment as convection continues.

As for the Atlantic: Still no development imminent due to a high shear environment across much of the tropical Atlantic. If this shear stays up (50 knots) then it will be difficult for the GFS/European to be right in the next 7 days when it forecasts a system to move off of the African coast. Last time I checked the shear forecast it looked like the shear should die down, however it has been holding steady for the last few days. But, if it does die, the wave coming off of Africa could have a chance. Wind a strong Bermuda high driving it westward, the east coast could be in danger. However, this is a long way away and there is no storm yet. Just something to watch here in the next week. In 7-14 days waves will start to pour off of Africa...likely leading to at least one storm.

Weather Synopsis

Current:

Surface/850hPa low situated over Lake Superior, with cyclonic flow on backside bringing strong northerly flow into western SD. Upper low (500/300 hPa) centered over central MN, leading to a decent cool pocket aloft, enhancing cumulus through the region. Surface heating minimized due to strong (30 knots, gusts to 40) NNW wind and partly cloudy skies. Currently only 67F in Philip and holding steady.

Today:

Will continue to see strong NNW winds through the afternoon, sustained near 30 knots, gusting to 40 due to a strong pressure gradient maximized over the Dakotas. This should hold down temperatures and not allow temperatures to maximize their potential, which should be around 78F (26C) with 3C 700 hPa temps. RAW NAM forecasts 77F today, as well as ETA/GFS MOS. However, all models are too warm at the moment, so will undercut a degree or so (75F today), which agrees with the NWS. Partly cloudy skies should be maintained through much of the afternoon with clearing towards the evening. If the clouds clear a little early then we might reach the model numbers.

Tonight:

Clearing skies should allow for good radiational cooling, except the models are forecasting the winds to stay up near 5-10 knots. RAW NAM forecasts 54F, with dewpoint of 50F. ETA MOS 49F, GFS MOS 53F. Last night, with winds 10 knots and dewpoint in the mid-40s, the low was 54F. Considering the dewpoint will be up a bit tonight and winds should be in the 5-10 knots range, we should see a low similar to last night. My forecast: 52F.

Tomorrow:

CLEAR! No models showing any clouds in the forecast for tomorrow. 850 hPa temps increase one degree C, and 700 hPa temps increase to 6C, leading to the possibility of highs maximizing near 84F (29C). As the 500 hPa low and surface low pull to the east, the pressure gradient should reduce considerably, resulting in much lighter winds, allowing for more heating. Decent mixing should still be possible with light winds around 10 knots, mixing to 725 mb. RAW NAM forecasts a high of 79F, ETA MOS 79F, GFS MOS 85F. Considering I am only learning about how high mixing occurs here at an altitude of 700 meters, its difficult to go against the agreement between the ETA MOS and Raw NAM. However, with the GFS MOS going much higher, and mixing forecasted to be substantial, I will go somewhere in between. My forecast: 83F.

Next Few Days:

GFS MOS ensembles have come into better agreement on the temperatures, with Monday in the upper 80s, and Tuesday in the low 90s. The RAW NAM/GFS both hint at the possibilities of upper 90s on Tuesday, the model trends will need to be watched for this possibility. Tuesday also begins the chance (20%) of thunderstorms and showers once again, leading to the greatest chance on Thursday (45%) as a shortwave trough moves through the region coupled with a surface low generating in western colorado driving a warm front into the NE/SD border region. The GFS currently keeps the precipitation shield to the south of the region throughout the next 5 days, but convection off of the hills is still likely as dewpoints will be rising as 850 hPa flow turns from the NNW today to easterly by Tuesday leading to dewpoints in the upper 50s on Wednesday. The unsettled weather should continue through the weekend as low level flow out of the SSE will commence, resulting in upslope convection. Severe weather looks possible Wed and into the weekend, depending on shortwave passages.

7-14 day outlook:

Highs will be much warmer as a large ridge builds over the western United States. Small disturbances in the flow through southern Canada could bring the chance of rain, but this should be minimal as the jet begins its annual treck to the north. Enhanced rainfall looks likely in the Southeast, just where they need it considering the drought last year.

A Small Reminder

Just a reminder to all future meteorologists, or even current ones that have slacked off over time: Never, EVER, just look at the 850 hPa level, the 500 hPa level and MOS to make a forecast. It turns out that just doesn't work, like my forecast from yesterday. I really didn't take my time in putting it together, and it turns out rain is looking like its another full day down the tube, and the temps are going to hold out of the 90s until at least Tuesday. Of course, I saw this in the GFS MOS Ensemble Output (I ignored the 97F forecasted by the basic GFS MOS for Monday...luckily!) which was showing highs only in the mid to upper 80s through Wednesday. I will start looking at things a bit more in depth once the 12Z model runs are out and put up a GOOD forecast. No more slacking off!

Weather Synopsis

Currently:

The storm system that brought the severe weather yesterday has moved east, bringing in partly cloud skies throughout western SD. Isolated showers/tstorms developing in far southwestern-southcentral SD at the time of this writing. Surface low pressure centered in southern Saskatchewan, cold front spanning down Dakotas/MN border region into Neb. 500 hPa low also centered over southern Saskatchewan, shifting southward.

Today:

Unsettled weather should continue today, as the 500 hPa low shifts southward out of Canada into eastern ND. This should leave a cold pocket aloft, allowing for isolated convection to develop, primarily over the higher terrain, as highs approach the mid to upper 70s. 850 hPa temps for the region will be near 20C in the SW, to 15C in the NW, with NNW flow. Dewpoint temperatures should drop through the day, approaching much more comfortable levels (mid-40s) by mid-afternoon.

Next few days:

The active weather pattern that has been persistent over the high plains will finally take a break as the region will enter the backside of a mid-lat cyclone, and enter a high pressure region, resulting in northerly flow for the next 36-48 hours. This should keep temperatures seasonably cool and comfortable today and tomorrow. However, these cool conditions will be short lived as by Saturday night into Sunday southerly flow will commence, resulting in much warmer conditions into the latter half of the weekend. Expect highs to approach the low 90s by Monday with 850 temps back up near 24C. This southerly flow will also lead the region back into a daily chance of showers in the higher terrain preceding to a shortwave passage mid-week (possible severe).


TROPICAL UPDATE:

Not much to mention at the moment, and thus I will keep this short. Currently there are no substantial tropical disturbances in the Atlantic, with a small cluster of thunderstorms currently in the Gulf and a tropical wave, which shows some convection, in the mid-Atlantic. Both locations have substantial dry air inhibiting storm development, and none of the reliable tropical models are predicting development from either system. The gulf storms have lost much of their convection in the last hour or so, and will likely fizzle as the day goes on. The Atlantic wave looks its best right now, but with the dry air and higher wind shear to the west (up to 50 knots) should keep it from developing.

The Tropical East Pacific, on the other hand, is very active, with Tropical Storm Boris looking very strong (possible hurricane in the next 24-48 hours) and a strong looking low pressure region to Boris' west. The low pressure region will have to intensify quickly if it will have any chance of developing (24 hours, or so) as it will be moving into a region of cooler sea surface temperatures (SST). Boris still has a few days of possible development time until it will be in the lower SST, thus strengthening is likely over the next 48-72 hours. The models are also predicting a third system might develop off of the Mexican coast (European, CMC, and GFS) and move up the coast towards the Baha. This will need to be monitored.

7-14 Day Period:

The GFS and CMC are beginning to forecast tropical development off of the coast of Africa in 7-10 days. SST in this area are supportive of development, but climatologically it is rare that a system develops this close to the Africa continent (at any time of the year, let alone July!). A very strong Bermuda high should keep any system that does develop on a west-northwest heading towards the Caribbean, or just to its north. The European model is also indicating enhanced activity in the Caribbean in 10 days as well. With a conducive MJO and a neutral ENSO forecasted at this same time period, the possibilities of an Atlantic Tropical system in the 7-14 day period look 'good'. I would put it at 35%.

Friday June 27th, 2008: Storm Chase

Yesterday was supposed to be the big chase day, when we would see our first high plains strong supercell. However, we ended up in a dead zone in Martin, SD, cut off from the south by a large MCS in Nebraska and Colorado. Strong moisture advection and convergence, a substantial moisture boundary (dryline), and shortwave were all converging on the region, but storm initiation was slow. This lead us to stop the chase a little early, and head home to Wall. Of course, once we pulled in the parking lot we looked southeast and there was a towering cumulonimbus right where we were located earlier. Lucky for us (and those in the area) it didn't develop into a tornadic supercell, but it illustrates the need for patience when storm chasing!

But the day was not at a loss, as a strong bowing line of storms developed in the SD/NE/WY border region and raced to the ENE towards the Badlands. This gave us an opportunity to witness some very impressive lightning over an hour and a half period while parked at the Pinnacles Overlook in Badlands National Park. It may not have been the supercell or tornado we were hoping for, but it was a nice consolation.