Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KAKQ 220315 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1115 PM EDT WED SEP 21 2016 .SYNOPSIS... A frontal boundary remains stalled along or just off the Southeast or Mid Atlantic coast into Friday morning, with low pressure lingering near the Southeast or Mid Atlantic coast tonight into Friday morning. High pressure builds over the local area Friday into Saturday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
Update... Flash Flood Watch extended through 400 AM and areal flood warnings also extended for another 6 hours across SE VA/NE NC. Shortwave energy rotating around the stacked low near the SC coast is becoming enhanced as it interacts with a deformation axis situated across south central VA. Rainfall is effectively training over these same areas with locally moderate to heavy rainfall at times. This trend will continue overnight, thus the reasoning to continue flood headlines since many areas within the flood warnings are still experiencing flooding and road closures with nowhere for the additional rainfall to go. Added a hydrology section to forecast discussion for the Cashie River near Windsor. See below for details. Previous discussion (616 PM)... Meanwhile, a dry slot seen in water vapor imagery is moving up the coast from the Outer Banks to as far north as Ches Bay attm. This is allowing precip rates/1 hr totals to diminish closer to the coastal areas of far SE VA/NE NC despite the continuous moisture feed coming off the ocean in onshore flow. Expect this trend to continue near the coast overnight...with moderate showers within a deformation axis located n-nw of the stacked low (best seen utilizing infrared imagery). Have adjusted POPs to account for the aforementioned precip trends this evening with light to moderate rain showers becoming focused closer to southeast coastal areas late tonight into Thursday morning. Previous discussion (424 PM)... Late this aftn, remnant lo pres that was tropical cyclone Julia was cntrd ovr ern SC. This lo pres area continues to pull bands of showers into the srn two thirds of the CWA, with moderate to heavy showers affecting much of the srn half of the region. Due to continued areal flooding going on acrs most of SE VA and NE NC, and additional rainfall between .50 inch and 2 inches possible in these areas thru this evening, have extended or expanded the Flash Flood Watch until midngt. Coverage and intensity of the pcpn will decrease overnight, and Pops will decrease rapidly as you go N of a Farmville to Petersburg to Wallops Island line. Lows tngt will range fm the mid 60s to lower 70s.
-- End Changed Discussion --
&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... A frontal boundary and lingering lo pres near the SE or Mid Atlc coast, will continue to result in at least hi chc pops (40-50%) acrs the Srn/SE portions of the region Thu into Thu evening. The combination of nrn stream energy and the upr lo/associated upr trough weakening, will finally result in Pops shifting offshr later Fri/Fri evening. Surface hi pres will bld over the region Fri evening into Sat morning. A backdoor front will then drops acrs the area during Sat. Expecting dry conditions Fri evening thru Sat. Highs in the mid 70s to lower 80s Thu, and in the upr 70s to mid 80s Fri and Sat. Lows in the 60s to arnd 70 Thu ngt, and in the mid 60s to near 70 Fri ngt. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A trough digs over the Northeast US Saturday night into Sunday as an upper level ridge builds over the Mississippi Valley. That ridge then slowly amplifies and pushes eastward Mon-Wed. Models have trended weaker with respect to pushing the associated cold front completely through the area on Sunday. Surface high pressure is progged to become centered over eastern Canada with a piece of the High ridging down into the northern mid-Atlantic states Sunday night into Tue (rather than actually building over the local area). While deep moisture will be pushed south of the local area, this pattern suggests that the sensible weather will still feature a persistent easterly low level flow with skies to avg partly to mostly cloudy Sunday (and perhaps Mon/Tue as well). Have also lingered 20% POPS for much of the area Sunday, shifting to the Sw zones Sun night/Mon. Highs will average in the 70s with lows in the upper 50s to mid 60s. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... A stalled frontal boundary remains near the coast this evening with weak low pressure continuing to slowly move across eastern NC. Weak high pressure is currently situated to the north of the area. Showers continue to move across portions of SE Virginia and NE North Carolina with a slight decreasing trend in coverage/intensity. Showers have also developed across central Virginia and continue to propagate west of RIC. Similar to the past few nights, tricky forecast is in store for IFR versus MVFR. Expecting stratus to develop in this moist airmass, thus have IFR conditions in the forecast for RIC/SBY/ECG with cloud decks hovering between 500-800 feet at these locations later tonight. Also cannot rule out the chance for showers at PHF/ORF/ECG, especially during the first half of the overnight period. Am expecting a gradual improvement in cigs to MVFR conditions during morning with cloud decks rising above 1000 feet across the region after 12Z. Winds across the area are generally onshore around 10-15 knots with occasional gusts. Outlook: Gradual improving conditions are expected Thursday into Friday as high pressure continues to build just north of the area. VFR conditions can be expected by Saturday. Another frontal boundary approaches the area Sunday into Monday. && .MARINE... SCA headlines are in effect for all coastal waters (through Thu night), for the lower/mid Bay (through tonight/Thu morning, and lower James/Currituck Sound through this evening. The wind slowly diminishes late tonight/Thursday, but seas remain 4-6 ft for Ocean waters. The latest data suggests low pressure emerges back over the ocean Thursday night into Friday, which suggests a modest 10-15kt nne wind continues. This will allow seas to remain 3-5ft, with 2-3ft waves in the mouth of the Bay. A cold front approaching from the N Friday night and pushing into the area Saturday is now looking to stall over the Carolinas by Sunday. Marginal SCA conditions are possible but appear less likely now that the cool surge behind the front may stay mainly N of the local area. && .HYDROLOGY...
-- Changed Discussion --
The Cashie River near Windsor is expected to reach major flood stage (which is 13.0 ft or above) around midnight tonight and crest near 14.6 ft around 200 AM tonight. The ongoing rainfall tonight into Thursday morning will keep river levels elevated within major flooding Thursday morning and within moderate levels (10-12.99 ft) through Thursday afternoon before slowly subsiding. The Cashie River is not expected to fall below flood stage until early Friday afternoon.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING... As of 22Z, tidal departures avg +0.5 to 1.0 ft over the marine area, so despite significant flooding from heavy rainfall across portions of Hampton Roads and northeast NC, actual coastal/tidal flooding has been minimal from this event with most sites falling short of Minor Flood thresholds by around 0.5 ft. Have allowed the Coastal Flood Advisory for the mid/upper James River zones to expire as High Tide has passed. Additional tidal flooding does not look likely for Thu but some areas (especially the upper James River may reach minor flooding again). Feel it is too marginal at this point for an advisory so will allow next shift to determine need for a statement or possible an advisory if departures were to increase more than is currently expected. For now, departures expected to continue at +0.5 to +1.0 ft through Thu/Fri. One explanation for the rather low departures may be due to water that has been able to exit the Bay into the Ocean fairly efficiently despite the persistent onshore flow. Will continue to monitor however, as tidal anomalies may build nwd through the Bay by Thu aftn which could lead to some marginal tidal flooding by that time farther up into the Bay. The beach hazard statement has been discontinued, with a moderate risk for Rips expected for Thu. && .AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...None. NC...Flash Flood Watch until 4 AM EDT Thursday for NCZ012>014-030- 031. VA...Flash Flood Watch until 4 AM EDT Thursday for VAZ092-093- 095>098. MARINE...Small Craft Advisory until midnight EDT Thursday night for ANZ634-656-658. Small Craft Advisory until 10 AM EDT Thursday for ANZ631-632. Small Craft Advisory until 4 AM EDT Thursday for ANZ638. Small Craft Advisory until 10 AM EDT Friday for ANZ652-654. Small Craft Advisory from 4 AM Thursday to 10 AM EDT Friday for ANZ650.
-- End Changed Discussion --
&& $$ SYNOPSIS...TMG NEAR TERM...BMD/TMG SHORT TERM...TMG LONG TERM...LKB AVIATION...AJZ/MAS MARINE...LKB HYDROLOGY...BMD TIDES/COASTAL FLOODING...AKQ

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.