Area Forecast Discussion
Issued by NWS Wakefield, VA
Issued by NWS Wakefield, VA
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302 FXUS61 KAKQ 170629 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 229 AM EDT Wed Jul 17 2024 .SYNOPSIS... Hot and humid conditions prevail through this afternoon ahead of a cold front. An unsettled period begins late this afternoon through Thursday, as a cold front pushes through the area and stalls across the Carolinas. Shower chances focus mainly over southern Virginia and North Carolina Friday, then return to all zones by Saturday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 800 PM EDT Tuesday... Key Messages: - Excessive Heat Warnings and Heat Advisories have been allowed to expire at 8 PM. - There is a Marginal Risk of severe weather late this afternoon through this evening for much of the area. Damaging wind gusts are the main threat with any stronger storms. Similar to the past couple of days, Bermuda high pressure remains anchored well offshore with a surface trough just east of the Blue Ridge mountains. Warm 850mb temps have resulted in a bit of capping across the area with showers and storms struggling. There are two zones that may still see isolated showers/storms, the NW Piedmont (from storms moving off the Blue Ridge) and NE NC (from storms in N central NC moving NE). Neither looks particularly robust at the moment. However, given favorable CAPE in NC NC and DCAPE across the NW Piedmont, gusty winds will be possible. SPC has much of the northern and western portions of the area highlighted in a Day 1 Marginal Risk for severe weather. Any shower/storm chances come to an end later this evening, with partly cloudy skies overnight. Temps as of 8 PM ranged from the upper 80s to around 90F across the area. Temperatures remain warm tonight with lows only falling back into the mid 70s to upper 70s (around 80 in the urban areas and along the coast). Location such as Norfolk may not get below 80F overnight given SSW winds remaining breezy through the night with gusts up to 20-25 mph possible. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... As of 330 PM EDT Tuesday... Key Messages: - Remaining hot Wednesday and humid area-wide but with a higher coverage of storms by afternoon. Heat Advisories are in effect for the entire area with the exception of the MD beaches. - Showers/storms become fairly widespread late Wednesday/Wednesday night through Thursday. - There is a Slight Risk for severe weather across the northern half of the forecast area Wednesday, with a Marginal Risk elsewhere. Better forcing tomorrow as a cold front begins to approach from the northwest and the strong upper ridge over the region begins to break down. Latest CAMs for tomorrow have storms beginning to fire late morning into the early afternoon along a lee trough just east of the Blue Ridge mountains, becoming more widespread and advancing further east later tomorrow afternoon through the evening hours. Even though mid level lapse rates are on the weaker side tomorrow and bulk shear will only be on the order of ~20 to 30 knots (greater than we have seen as of late), we will have plenty of instability over the region with MLCAPE climbing in excess of 2000 J/kg by tomorrow afternoon. Storms will primarily be mainly be linear clusters, but a marginal supercell or two cannot be ruled out. The main threat with the strongest storms tomorrow will be damaging wind gusts. SPC has highlighted the northern half of the forecast area in a Slight Risk for severe weather and a Marginal Risk elsewhere. In addition to the severe weather threat, there will also be a localized heavy rain threat as moisture pools ahead of the front, and PWATs surge to 2.25+". It will also be one more hot day tomorrow, with temperatures climbing into the mid to upper 90s combined with dewpoints in the mid to upper 70s, making it feel like 105-109 degrees. A few locations may approach or exceed 110F+, but lower confidence tomorrow compared to today, especially with more cloud cover and increasing shower/storm chances. All of the area has been included in a Heat Advisory for tomorrow with the only exception being the MD beaches. The cold front gradually pushes south through the region Wednesday night and through the day Thursday, before eventually stalling near the NC/VA border Thursday night. Highest shower/storm chances will be focused across the southern half of the area on Thursday. Locally heavy rainfall will be possible, with a Day 2 Slight Risk ERO for far southern Virginia and northeast North Carolina. There is a Marginal ERO for the remainder of the forecast area. Widespread clouds and rain on Thursday will keep temperatures in the 80s. The front pushes just south of the local area Thursday night into Friday, with the highest rain chances confined to the southern areas. Drying out for the northern half of the area Friday, with only scattered shower and storm chances by Friday afternoon. High temperatures will again be in the 80s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 300 PM EDT Tuesday... Key Messages: - Daily rain chances persist as the front lifts back north and stalls over the southeastern portion of the area. - Temperatures look to stay near normal. Upper trough moving into New England looks to flatten out later Friday while the area of high pressure off the Southeast coast begins to gradually retrograde back westward slightly. The front is forecast to lift back north into the southeastern portion of the area and stall out into Saturday. The best rain chances Friday night will be across northeast North Carolina in the vicinity of the boundary, then chances spread back north on Saturday as the front shifts. The higher rain/storm chances on Saturday will be south of the I-64 corridor. A positively tilted trough will start to dip down into the mid Mississippi Valley on Sunday allowing our flow to become more southwesterly. The stalled front won`t move very much, so rain chances look to remain fairly similar into early next week, with the southern half of the area having the best chance for rain/storms. After a brief, partial break from the humidity (especially up north), 70+ degree dewpoints will stream back into the area for this forecast period making it feel humid once again. The somewhat good news is that temperatures aren`t expected to be nearly as hot during the extended period as they have been, with high temperatures forecast to top out in the mid to upper 80s, which is right around or even slightly below normal for this time of year. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... As of 200 AM EDT Wednesday... VFR conditions prevail into this aftn ahead of an approaching cold front, with SSW winds ~10kt, increasing to 10-15kt with gusts to 20-25kt by late morning. SCT-BKN cumulus develops during the aftn. Scattered showers and storms will mainly be W of the terminals until late in the aftn, will have mention of VCTS starting in the 20-23Z timeframe, with prevailing SHRA at all but ECG 23-01Z and thereafter into tonight. Gusty winds and heavy rain will be possible with any storms, with IFR-LIFR flight restrictions in VSBY. Gusty winds in excess of 40kt will be possible in the storms as well, especially at RIC/SBY. Showers and storms taper off from W to E later tonight as forcing weakens. Outlook: The cold front lags back to the NW into Thu morning, then pushes S through the FA on Thu with scattered to numerous showers and storms redeveloping. Thunder chances decrease across northern areas by later in the day, becoming more focused across southern VA and NC. Periodic flight restrictions (mainly VSBYs) are expected due to locally heavy rain along with gusty winds. The front will push farther S Thu night into Friday as drier air pushes in from the NW. The boundary lifts back N Saturday. The chance for showers/tstms is less Friday (except over far SE VA/NE NC) and then increases again Saturday. Sunday will see scattered, mainly aftn/evening showers/storms. && .MARINE... As of 300 PM EDT Tuesday... Key Messages: - Southwesterly winds will increase overnight into Wednesday as the pressure gradient tightens ahead of an approaching cold front. -Rain chances return later Wednesday into Thursday, then remain a daily chance as the front stalls out across the area. High pressure remains well offshore this afternoon with some lee troughing persisting over the local area. South/southwesterly winds of 12-16kt will prevail into the overnight hours and Saturday morning. An approaching cold front could help tighten the pressure gradient a bit over the local waters, especially the southern Bay tonight and early Saturday. Guidance continues to cap speeds right at the bottom-end of SCA thresholds for only a few hours, so refrained from issuing any headlines at this point. Winds will subside slightly in the Bay during the day, while the coastal waters will have southerly winds of 15-18kt into early Thursday. Waves in the Bay will become 2-3ft, with seas building to 4-5ft across the north and 3-4ft down south with the elevated southerly wind. Rain and storm chances also increase tomorrow and Thursday as the front moves in. There will be the threat of gusty winds with any stronger storm that develops. Conditions subside late Thursday and Friday as winds become north/northeasterly at 8-12kt behind the front. Seas will be 2-3ft with 1-2ft waves in the Bay through the weekend. With the front stalling over the local area, expect daily rain and storm chances to continue. It won`t be as hot as it has been, but humidity will likely remain higher. Rip current risk remains low at all beaches today. The rip risk increases to moderate at the northern beaches (including Ocean City) Wednesday and Thursday. For now, kept southern beaches at a low risk. && .CLIMATE... A record high min temperature was tied yesterday/Tue 7/16 at SBY. Records are listed below for today/Wed 7/17. Record highs are unlikely and although record high mins may be challenged, showers and storms late in the day/tonight may lead to calendar date mins lower than what is observed this morning. - Record Highs: - Site: Wed 7/17 - RIC: 100 (1980) - ORF: 100 (1887) - SBY: 99 (2012) - ECG: 99 (1942) - Record High Mins: - Site: Wed 7/17 - RIC: 76 (2005) - ORF: 80 (2021) - SBY: 80 (1983) - ECG: 80 (2019) - Highest 1-hr Heat Index Value on record (P.O.R. 1948-2024): - RIC: 117 (7/17/1980) - ORF: 118 (8/18/2017) - SBY: 122 (7/15/1995) - ECG: 119 (7/5/1999) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for MDZ021>024. NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for NCZ012>017-030>032-102. VA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for VAZ048-060>062-064>069-075>090-092-093-095>100- 509>525. MARINE...Small Craft Advisory until 7 AM EDT this morning for ANZ630. Small Craft Advisory until 10 AM EDT this morning for ANZ631- 632-634-638. && $$ SYNOPSIS...LKB NEAR TERM...AJB/RMM SHORT TERM...AJB/LKB LONG TERM...LKB/JKP AVIATION...MAM MARINE...JKP/RHR CLIMATE...