... Chilly weather with gusty winds is expected today, with winds decreasing late tonight. High pressure will pass across the region Wednesday, with temperatures rebounding closer to normal values. The next storm system will bring widespread rainfall Thursday through Saturday. Drier weather is forecast for the end of the weekend.
NEAR TERM /THROUGH TODAY/... As of 230 AM EDT Tuesday...
Cold and windy today.
A closed low over the eastern Great Lakes will shift off the Del Marva Peninsula by tonight. The short wave responsible for yesterday's severe weather will stay just to our northeast today. A coastal low was deepening off the Carolinas and pulling the majority of the system's energy east. This low will deepen over 20mb in the next 24 hours, and reaching the Long Island/Cape Cod vicinity by late tonight...overtaking another surface low in a Fujiwhara effect.
Associated cold front is already east of us, and will be well offshore later today. A lee trough remains in the area, and cold air stratus will continue to bank along and west of the Blue Ridge with strong upslope flow. The radar mosaic this morning shows just few sprinkles/drizzle. A 40 to 45 kt LLJ ushers in much drier air throughout the day, and expect any remaining precipitation to gradually retreat northeast, only affecting the Greenbrier Valley of WV. In the meantime, will keep low chances for showers along and west of the Blue Ridge.
The most notable weather element today will be the wind. With unidirectional flow throughout the layer and good mechanical mixing, along with a a tight pressure gradient remaining as the surface low to our east deepens, expect winds of 15 to 25 mph with gusts up to 50 mph. This will continue through about tonight before slacking off somewhat. The area along and just downwind of the Blue Ridge mountains will have the highest chance of seeing these speeds, and have extended the wind advisory through 8 pm. The advisory now extends from Boone, NC, to Warm Springs, VA.
Otherwise, strong CAA today will make things quite chilly over the mountains, where highs will only be a couple degrees or so warmer than they are currently, resulting in afternoon temperatures in the 40s and 50s. The mountains will help bottle up the CAA, so that areas to the east in downsloping winds can expect highs in the upper 50s to low/perhaps mid 60s. Overall, it will be a cool, windy day, with stratus clearing out very late over the mountains and foothills. Skies will clear out southeast of the Blue Ridge by later this morning as the winds pick up.
Tonight winds decrease to about 10-15 mph with the occasional higher gust, especially over the ridges. Stratus remains along and west of the Blue Ridge escarpment, and will keep temperatures from dropping below freezing. Readings will range from the 30s west to the mid 40s east.
Forecast confidence is moderate for PoPs, winds and temperatures.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... As of 200 AM EDT Tuesday...
Heavy rain still likely late Thursday/Thursday Night.
An anomalously deep upper level low is forecast to move over the mid-south region by late Thursday night. NCEP Ensemble forecasts indicate 500mb heights will be over 3 standard deviations below average in the southern U.S. Thursday evening.
For our area,an impressive and anomalously strong inflow of moisture from the Atlantic arrives on Thursday with this sustained moisture feed shown in the 1000-700mb moisture transport vectors to continue through Thursday night. This strong moisture feed interacting with the east facing slopes of the Blue Ridge will bring the potential for flooding to our region and will continue to highlight this threat in our HWO. Widespread 1-2" rainfall totals appear likely with higher values along the eastern slopes of the Blue Ridge.
Before this feed of moisture develops, ridging on Wednesday will keep conditions dry and winds will diminish with a weakening pressure gradient. Leaned toward the warmer guidance values for highs on Wednesday. Winds should stay up Wednesday morning to prevent frost, but will need to monitor the NW NC mountains where sfc ridge begins to build early Wednesday morning.
LONG TERM /FRIDAY THROUGH MONDAY/... As of 200 AM EDT Tuesday..
Cloudy, damp and cool conditions give way to dry weather by late in the weekend.
The long range model guidance is in generally good agreement on the large scale evolution and track of the anomalously deep upper level low, but there are some uncertainties with the amplitude and timing of this feature. The EPS, GEFS and CMCE ensemble clusters suggest this upper low opens and shifts east of our area on Sunday with a zonal flow expected Monday.
Axis of highest PWAT air shifts to the north on Friday, and the low level flow turns more to the south/southwest which should help reduce rainfall rates. Scattered to numerous showers, with lighter rainfall totals, are still possible Friday due to the proximity of the upper level low, and precip chances gradually wane during the weekend as the upper low weakens and slowly lifts north of our area allowing for westerly low level flow.