:: Memorial Day Weekend
ETA Model predicted temps 7pm Sunday
My last entry examined the convective potential of the storm system slowly moving out of MN today. The MCS I was looking for evolved into a textbook squall line along the I-29 corridoor on Tues night. These storms hit mature stage quickly, topping out around 45000 ft within 2 hrs of initial development. This occuring after sundown, and with no low level flow "pushing" behind the storms for a faster eastward pace, only remnants grazed Lakeville in the early AM hrs yesterday. The front passed through much later than expected as well, allowing temps to rise up on a southerly flow quite quickly yesterday. We hit 83 here, and then temps fell off sharply as a secondary shortwave trough cycled through and brought a round of showers after about 6pm.
Looking forward to the holiday weekend presents us with the potential of 90 degree weather almost to a point of certainty. Our current weather maker is yet another cutoff low, now located in the Wasau-Stevens Pt., WI vicinity, and sliding southeast. There is an impressive surface ridge over the Four Corners that is expanding eastward quickly, and it will push out the low without much more adeiu.
The ridge has some maritime tropical origin and has warmed significantly over the desert SW. As it broadens its coverage east of the Rockies, it will park the upper jet on the Canadian Shield tomorrow, allowing the warmth to build back in...a surface low will form near Devils Tower, WY, and a trough will form up along the Front Range. As this low deepens at the surface, the jet will trough in earnest in the Pacific NW, swinging around the low and then streaking back up northward to Canada. This will be the catalyst for a strong southerly flow for MN.
Models are showing a 60+ kt low level jet streak, ushering hot and humid conditions into MN for the weekend. We can count on 85 pushing 90 for Saturday with a warm, humid southerly breeze for the bass opener - and no precip in the cards that I can see. As we approach Sunday and Monday, my concerns turn to covective potential. The models hold extremely high dewpoints through the weekend, and moderate precipitable water values - so saturation is present. CAPE values on the 12Z ETA run soared in Central MN Sunday evening to 3500-4000 J/kg, and lifted indicies are moderately high as well...the problem is that the ridge will still be in control, and vorticity models do not concur for development -- and the Devils Tower low will still be omega blocked by the ridge.
So...Memorial Day is our first potential day for precip of the weekend...but timing is a problem. This far out the models are not presenting much certainty for timing of frontal passage. As the weekend moves on, I will try to post some updates on precip chances for the holiday.
THURS AFT/EVE - Mostly Cloudy, 30% chc showers, high 72, NW wind 10-15, low 56
FRI - Sunny. Warmer, with a high of 84, winds N, shifting to W by midday 5-10
FRI PM - Clear, light SE wind 5-7, low 64
SAT - Sunny, humid. High 87, SSE wind 10-15 mph, low 72
SUN - Hot and Humid, Partly Cloudy by afternoon, High 92, South wind 5-10, low 72
MEMORIAL DAY - Partly Cloudy and Warm, High 86, 40% chc Thunderstorms in evening