Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 241813 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 113 PM EST Mon Feb 24 2020 .SYNOPSIS... A warm front will lift north across the Carolinas tonight and Tuesday. A storm system over the Midwest will move into the Great Lakes, dragging a cold front across the region Wednesday. High pressure will move into the Southeast late in the work week. && .NEAR TERM /THROUGH TONIGHT/... As of 100 PM Monday... A low pressure system will approach the region from the west as the parent upper low over the Plains opens into a shortwave as it swings northeast through the MS Valley toward the Great Lakes/Northeast. Meanwhile, the parent trough will deepen over the Plains as another low dives south out of Canada through tonight. As the upper level wave weakens, the surface low will stall over the OH Valley. Rain will continue to move into central NC from the southwest through tonight. As the surface low stalls, so will the cold front to the west. As a result, the Carolinas will be under the influence of deep southwesterly flow advecting warm, moist air into the area through the rest of tonight. The rain may be intermittent and spotty through the remainder of the afternoon, increasing in coverage and intensity later in the aft/eve and continuing into the overnight hours. Clouds will also continue to thicken and lower as the atmosphere moistens. Lows will be a little tricky but expect mid 40s NW to around 50 degrees SE. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 100 PM Monday... The parent upper level trough/low over the Plains will swing through the Midwest on Tuesday, absorbing the remnants of the s/w over the OH Valley as it moves east. At the surface, the low and attendant cold front to the west will linger nearly stationary Tuesday and Tuesday night while the axis of heaviest rainfall progresses eastward with the effective cold front through Tuesday night. In fact, according to the latest model solutions, the majority of the rainfall should be through all but far eastern portions of the area by early Tuesday, with the rest of the day potentially dry. The low and secondary cold front will then strengthen once again as the upper low approaches, progressing eastward thereafter (Wed/Wed night). With the continued WAA into the area, highs Tuesday are expected to top out in the low 60s NW to mid 60s SE. Lows Tuesday night should also be somewhat mild but may depend on the timing of the secondary cold front moving into the area. Expect upper 40s NW to upper 50s SE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 350 AM Monday... Wednesday and Wednesday night: Additional mid/upper level energy will lift from the mid/upper MS River Valley into the Great Lakes region Wednesday into Wednesday night. An associated trailing strong cold front is forecast to move through central NC late Wednesday into Wednesday night. The best combination of lift and moisture is expected to be to the north of central NC. However, with low and mid level lapse rates increasing ahead of the cold front we could see enough instability develop ahead of the front to support so isolated to scattered showers late Wednesday afternoon/evening. Thus, will maintain slight chance pops south/southwest to chance pops elsewhere (maximized across northern portions of the area). High temps on Wednesday are expected to be in the 60s, with possibly even some lower 70s across the southeast, with breeze southwesterly winds in the 10 to 15 mph range with possibly some gusts of 20 to 25 mph. Dry weather is expected to remain after midnight, with low temps by Thursday morning expected to range from the lower 30s northwest to near 40 far east/southeast (driven by CAA). Thursday through Sunday: The deep mid/upper level low is expected to slowly wobble eastward while filling some, moving from the Great Lakes region eastward across southern Canada and New England. This will maintain a fairly deep l/w trough across the eastern U.S for a majority of the period, with the main trough axis shifting to the east of central NC by Saturday night/Sunday morning. This will result in generally dry weather, though we will need to keep on eye on the potential for clipper systems diving southeastward out of Canada and moving through the base of the trough. Such system are very hard to track this far out in time. Regardless, these systems will have little moisture to work with, and will continue to advertise a dry forecast (just something to be aware of). Below normal temps are expected during this time frame, with highs in the 40s and 50s (coldest on Saturday) and lows in 20s to lower 30s (coldest Sunday morning). && .AVIATION /18Z MONDAY THROUGH SATURDAY/... As of 1225 PM Monday... 24 hour TAF period: Most sites remain VFR as of 18Z this afternoon. Light rain will continue to move into the area from the southwest today, lowering cigs/vsbys from SW to NE over the next several hours. Conditions will quickly deteriorate this aft/eve as the rain increases in coverage and intensity, with all terminals dropping into the IFR/LIFR range tonight. However, confidence on exact timing is not terribly high. Southwest winds may increase a bit to 5-10 kts at times, with brief periods of gustiness into the mid teens across the east overnight. Expect a period of LLWS migrating from NW to SE overnight and while the duration is likely longer in the TAF than it will be in reality, wanted to cover the uncertainty in timing. Looking ahead: As a cold front approaches from the west and moves across the area Tuesday night into early Wednesday, expect periods of sub VFR conditions across central NC. Aviation conditions will improve for Thursday through Saturday as a drier air mass moves into the region. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...RAH NEAR TERM...KC SHORT TERM...KC LONG TERM...BSD AVIATION...KC is the U.S. government's official web portal to all federal, state and local government web resources and services.