Area Forecast Discussion
Issued by NWS Wilmington, NC
Issued by NWS Wilmington, NC
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811 FXUS62 KILM 231924 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 324 PM EDT Thu May 23 2024 .SYNOPSIS... Shower and thunderstorm chances will grow as a series of upper level disturbances move across the region Friday through Saturday, while a front stalls just north of the area. Inland temperatures will rise into the lower 90s by Sunday, then cool back towards normal by Wednesday behind a cold front. && .NEAR TERM /THROUGH FRIDAY/... A ridge axis extending northeastward from a mid and upper level high centered over the Gulf of Mexico will move off the Carolina coast this evening. Behind this ridge the westerly flow near and above 700 mb will bring cooler air overhead, removing the convective cap that has remained across the Carolinas for the past several days. Precipitable water along the coast should increase from around 1.2 inches this morning to 1.8 inches by Friday morning. A series of upper level disturbances should begin to arrive tonight, each potentially accompanied by a wave of showers and thunderstorms. Timing of these disturbances starts easy but gets more muddled with time. Disturbance #1 is discernible in water vapor imagery now across central TN into Alabama and should move across the eastern Carolinas tonight. My forecast shows an increasing trend in inland PoPs after 9 PM, peaking around 40 percent late in the evening, then diminishing again after 1 AM. It`s less likely this initial wave will reach the coast intact although clouds should certainly increase. Forecast lows are generally in the upper 60s inland to around 70 on the coast. Mesoscale subsidence behind tonight`s initial impulse may keep convection isolated Friday morning, but renewed convective activity should develop during the afternoon hours as surface-based instability rises to near 2000 J/kg and modest DPVA overspreads the region in advance of another disturbance slowly approaching from the west. High-res models suggest the seabreeze front should be a significant trigger for convection, and my forecast PoPs are highest (60 percent) just inland from the coast. Forecast highs are in the upper 80s, except lower-mid 80s at the beaches. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... Still expecting an active pattern for the weekend via the mostly zonal mid level flow and embedded short waves. Of course the inland Piedmont Trough and to a lesser extent the sea breeze will play a part as well. The highest pops occur Friday night and again Saturday pm. Guidance is trending toward formidable NVA in the wake of Saturday`s system for Sunday and pops may need to be reduced further there if this continues. Temperatures look to remain above climatology throughout. && .LONG TERM /MONDAY THROUGH THURSDAY/... Active pattern continues for the first part of next week as the west to east mid level flow pushes to the south slightly with remaining embedded shortwaves. It appears the best forcing in several days may occur Tuesday evening when all of the elements (surface front, mid level height falls) combine. Beyond this still expecting dry conditions to develop along with cooler temperatures. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... VFR cumulus clouds across the area should have trouble growing through a cap of warm air 6k-10kft this afternoon. This may change this evening as the high shifts farther offshore and an upper level disturbance approaches from the west. Moderate chances for thunderstorms appear at the KFLO and KLBT airports beginning at 02z. Chances are low that this convection will make it down to the coast after 06z. Assuming there is some rain inland, low stratus should appear around 10z, likely burning off shortly after sunrise. Extended Outlook...Scattered thunderstorms will be accompanied by short-lived IFR visibility at times through the weekend into Monday. The best potential appears to be Friday and Saturday afternoons when thunderstorm potential grows to or beyond 50 percent inland. && .MARINE... Through Friday...Surface high pressure will retreat east to near Bermuda tonight as a series of weak upper level disturbances begin to move across the Carolinas from the west. Synoptic winds will remain south to southwest at less than 10 knots, however some higher winds will persist along the coast through this evening due to today`s well- defined seabreeze circulation. Additional periods of stronger winds could accompany scattered thunderstorms on Friday, expected to be most numerous during the afternoon hours. A few of our high-res weather models including the HRRR explicitly indicate west to northwest thunderstorm outflow winds developing along the South Carolina coast late Friday afternoon. Outside of any thunderstorms, sea heights of only 2 feet are expected through Friday consisting of an eight second easterly swell plus local wind chop. Friday night through Tuesday...Overall light winds will persist into the weekend from the south to southeast as the pressure pattern remains weak. In time the flow will turn more from the southwest and increase a bit in magnitude. This occurs early next week. Significant seas will be 2-3 feet this weekend perhaps increasing to a range of 2-4 feet early next week. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...Coastal Flood Advisory from 9 PM this evening to 1 AM EDT. SC...None. MARINE...None. && $$ SYNOPSIS...ILM NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...TRA MARINE...TRA/SHK