Area Forecast Discussion
Issued by NWS Wakefield, VA
Issued by NWS Wakefield, VA
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007 FXUS61 KAKQ 120803 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 403 AM EDT Fri Jul 12 2024 .SYNOPSIS... A frontal boundary will remain nearly stationary across central Virginia today, slowly pushing east to the coast late tonight into Saturday morning. Ample moisture in the vicinity of the front will allow for widespread showers and storms through Friday night. The front gradually washes out over the region Saturday, with dry conditions returning Sunday through the middle of next week. Heat returns later in the weekend through the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM EDT Friday... Key Messages: - Flood Watch in effect for all but the far NW portions of the area through this evening. - Heavy rainfall continues to spread inland towards the I-95 corridor this morning, will linger through the day, before gradually shifting back east and slowly weakening tonight. The latest analysis indicates an upper level trough well off to our NW across the Great Lakes, with a strong upper level ridge well offshore in the western Atlantic. To our south, a weak upper low is cutoff from the main flow across the SE coast, and continues to transport ample moisture into the local area. In association with this, an inverted sfc trough is in place roughly along the stationary front which correlates well with the SPC mesoanalysis showing a large area of 2.20" to 2.30" Precipitable water extending along the I-95 corridor through NC into southern VA, spreading NNE to the MD eastern shore. Regional models and CAMS show the heavy rainfall focused this morning along the front, along with some modest 850mb frontogenesis across the region. There is fairly good agreement on the heaviest rainfall today occurring inland from the coast in the vicinity of the I-95 corridor from metro RIC south, and extending a little to the E of the I-95 corridor to the N of metro RIC. The latest 00Z/12 HREF continues to show this general area with >70% probs for 1"/3 hrs and 10-30% neighborhood probs for 3"/3 hr. As such, the Flood Watch remains in effect for all but the extreme NW portions of the FA as well as the eastern shore to the east of Dorchester Co. Expect the very efficient rainfall rates to continue into this evening with precipitable water values continuing to be well over 2". Thunder chances later today will be highest over the SE so locally higher rainfall amounts will be possible there as well. The widespread heavy rain is expected to diminish in coverage tonight as the boundary weakens and shifts back east towards the coast as the upper level SW flow finally begins to increase. Highs today will average in the upper 70s to lower 80s over the W and central portions of the FA, with mid 80s to the east. QPF average amounts will be 1.50-2.20" through tonight, but as occurred yesterday, much higher local amounts in excess of 5" will be possible. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... As of 335 AM EDT Friday... Key messages: - Remaining unsettled Saturday, but gradually improving by Saturday night. - Another round of hot weather starts on Sunday. The front will take through at least Saturday afternoon to move to the coast. Will continue with likely PoPs into Saturday for areas closer to the coast, and chc PoPs elsewhere. By Sunday, the front stalls out just offshore. Will need to keep chance PoPs in on Sunday for SE VA/NE NC but rainfall amounts do not look significant. Main concern for Sunday will be the returning heat with mid 90s forecast for much of the area leading to heat index values above 100F. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 355 AM EDT Friday... Key Messages: - Above average temperatures take hold once again Monday through Wednesday with heat index values of at least 105F likely for most of the area (with localized 110F+ possible over the E/SE). The models remain in decent agreement that the early to middle part of next week will see a return of very hot and humid conditions. Some of the models suggest somewhat drier air with ample mixing of the dew pts into the upper 60s along and W of the I-95 corridor and in theory this makes sense given the origin of the upper ridge is more continental. However, given the midsummer timeframe and the expected heavy rain into Saturday, this may be overdone. Have split the difference for now, going close to NBM high temperatures overall (highs into the mid to upper 90s, with Tuesday probably the hottest day with a few areas perhaps flirting with 100F). Went close to NBM dew pts across the SE, but a few degrees drier over inland areas. This still yields heat indices fairly widespread ~105F+ Mon- Wed, with some localized 110F+ possible in the SE. The upper ridge eventually breaks down as strong upper trough translates south front north central Canada and to eastern Canada late in the week. Will have chc PoPs starting in the NW late Wed, and all areas through Thursday with a cold front into the local area. For now, highs Thursday are forecast in the lower 90s S/SE with mid/upper 80s NW. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... As of 200 AM EDT Friday... IFR-MVFR conditions prevail in areas of heavy rain with embedded tstms early this morning (RIC/SBY), while MVFR-VFR conditions prevail elsewhere with a more scattered nature of showers/tstms across SE VA and NE NC. Unsettled flying weather continues today, with RIC expected to see the most widespread flight restrictions, while areas closer to the coast become mainly VFR with just periodic MVFR-IFR conditions possible in heavy downpours. Outlook: Unsettled conditions continue into Saturday with occasional degraded flight conditions as the front remains in the area. Conditions gradually improve Sunday, and will be mainly VFR Monday/Tuesday with dry WX. && .MARINE... As of 345 AM EDT Friday... Key messages: - SCAs in effect for most marine zones today for SE winds of 15-20kt and seas of 4-5ft. -Improving conditions expected Saturday. Remaining benign through the early week period. -High rip current risk at all area beaches today. A quasi-stationary boundary is located roughly along I-95 early this morning, and a broad area of low pressure has formed along the front on the GA/Carolina coast. The Bermuda high remains stationed well offshore. Southerly winds are generally 5-10kt with a few sites showing 10-15kt as of latest obs. Latest buoy obs indicate seas rising to 4-5ft and waves are 1-2ft. Low pressure will gradually nudge north through the day, allowing SSE winds to increase. This afternoon, winds will be 15-20kt over the bay and coastal waters, 10- 15kt in the rivers/Currituck sound. Unsettled conditions are expected today, so winds and waves may be higher within storms. However, gusts with these should generally be less than 34kt. Seas will be 4-5ft today, perhaps up to 6 in southern waters. Waves will be 2-3ft in the bay, 1-2ft in the rivers/sound. SCAs are already in effect for the coastal waters on account of rising seas, and SCAs for the bay/Currituck sound will go into effect later this morning. The rivers (excluding the upper James) will have SCAs go into effect in the early afternoon. Winds will remain breezy through early Sat, but should fall below SCA thresholds late tonight. Seas will take a bit longer to fall below 5ft, but should be able to take down SCAs in coastal waters by Sat afternoon. The front and low pressure along it will gradually weaken/dissipate over the weekend. By Saturday afternoon, winds will be starting to take on more of a westerly component and be down to 5-10kt over the bay/river and 10-15kt over coastal waters. Much lighter winds are expected Sunday. Westerly winds will be around 5kt in the morning, then turning to the south/southeast in the afternoon as the seabreeze kicks in. Conditions remain benign through the early week period. The rip current risk for all area beaches has been upgraded to high risk on account of 4-5ft seas, onshore winds, and periods being on the longer side at 7-8 seconds. Will maintain the moderate rip current risk for Saturday given seas will be diminishing through the day. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Flood Watch through this evening for MDZ021. NC...Flood Watch through this evening for NCZ012>017-030>032-102. VA...Flood Watch through this evening for VAZ060>062-064>069- 075>090-092-093-095>098-100-510>525. MARINE...Small Craft Advisory from 7 AM this morning to 6 AM EDT Saturday for ANZ630>634. Small Craft Advisory from 1 PM this afternoon to 7 PM EDT this evening for ANZ635-636-638. Small Craft Advisory until 10 AM EDT Saturday for ANZ650-652- 654-656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB/MRD LONG TERM...LKB/MRD AVIATION...LKB/RHR MARINE...AM