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.