Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 122336 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 636 PM EST Thu Jan 12 2017 .SYNOPSIS... A backdoor cold front drops through the area late tonight into Friday morning as high pressure builds over New England. Periods of unsettled weather are expected late Friday night through the weekend. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 200 PM this aftn, it appears that all climate records (with the exception of Norfolk) will either tie or break high temperature records for today, Jan 12. See climate section below for details. A trough of low pressure will straddle a cold front that extends from wrn Quebec, along the Eastern Great Lakes, across the Ohio Valley and into nrn TX. The trough/front will approach the area through this evening and allow sw wind gusts of 20-30 mph to persist during this time. Winds should diminish shortly after sunset but remain breezy overnight; minimizing any fog potential. Clouds should clear briefly late this aftn into early evening and then thicken/lower late this evening and overnight as the front passes through most of the area from nw to se after midnight tonight. Only a small dip in diurnal temps expected tonight with lows in the lower 50s (possibly upper 40s MD Lower Eastern Shore). && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... The cold front pushes se of the Mid Atlantic Region by mid-late morning with no precipitation anticipated. Dewpoints will plummet immediately behind the front as winds veer to the north, however temperatures will be more slow to respond as colder 850mb air does not arrive until early Fri evening. Therefore, high temps may not be as warm as Thu but will be around 5-10 degrees above normal. Low-mid 50s north and upper 50s to lower 60s south. Sfc high pressure (around 1045 mb) builds north of the area through Sat and wedges into the area...becoming reinforced by another sfc high (about 1035 mb) Sat night/Sun. Meanwhile, a strong upper level ridge (590 dam) sits over the Southeast/Gulf of Mexico Fri through Sun. The placement of these two features will create a squeeze play of moisture/shortwave energy that will stream unimpeded across the region late Fri night into Sun. Models continue to vary in overall shortwave strength and periodicity during this timeframe, however they all agree with bringing periods of precipitation over the cold air wedge/lee trough after midnight Fri night (which is 3-6 hours slower than previous 12z model runs) into Sat and again on Sun. Precip should begin as all rain until temperatures can cool to or below freezing across far nrn counties along/above a Fluvanna/Louisa to Accomack VA line (staying just north of Richmond) thus creating precip-type challenges. Still anticipating a primarily sleet event with pockets of light freezing rain mixed in. A brief period of snow within the wintry mix may even be possible early Sat morning across the MD Lower Eastern Shore. Remaining srn areas will see all rain. Lows Fri night in the lower 30s north and in the mid- upper 30s south (around 40F coastal NE NC). Limited warming on the order of 5 degrees or less anticipated for Sat as the area remains wedged in cold air and under cloudy skies with light onshore winds. Highs Sat in the upper 30s far north; otherwise lower 40s elsewhere. Wintry mix should hold steadfast across the north throughout the morning...gradually changing to all rain from south to north as temps slowly warm above 35F. Otherwise, all rain south. If any ice/sleet/snow accumulation occurs, amounts should easily be a few hundredths of an inch at best. Overall liquid precip totals should average 0.10 inches or less (possibly up to 0.15 inches across nrn counties). Models in generally good agreement with having a brief break in precip Sat evening and overnight...returning again for Sun as another batch of moisture/energy overrides the cold air wedge in place across the region. Overall precip-type should be all rain Sat night into Sun. One exception will be the MD Lower Eastern Shore where pockets of light freezing rain could linger into Sun morning before transitioning to all rain on Sun. Warming on Sun will be limited once again by the cold air wedge in place under continued cloudy skies and light onshore winds. Highs generally in the 40s. Wintry precip potential Fri night into Sun will continue to be highlighted within the Hazardous Weather Outlook. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Frontal boundary remains south of the fa Sun night before lifting north as a warm front Mon. Will continue to carry low end pops for light rain/drizzle in cool wedged airmass Sunday night into Monday morning. Could see some light freezing rain/drizzle across the lower Maryland eastern shore early Monday morning as temps drop to near 32. Otw, just liquid expected as reading stay above freezing but remain in the 30s. Highs Mon from the mid 40s N to lwr 50s S. The warm front lifts north of the region Mon night as strong low pressure tracks from the midwest (where an ice storm is expected) NE into the upr Gt Lakes region by mid week. This slow movement keeps AKQ fa in warm sector for most of next week thanks to high pressure off the sern coast. Models differ on timing of the trailing cold front across the area (GFS faster) but are coming together for a rather strong fropa with a possible triple point low tracking just north of the area late Thurs/Thurs night. Pcpn becomes more scattered and showery in nature due to being in the warm sector. Kept thunder out of forecast with the late week fropa for now. Highs Tues lwr 50s ern shore to lwr 60s SW. Lows Tue night in the 40s. Highs Wed from the mid 50s to lwr 60s south. Lows Wed night mid 40s to mid 50s. Highs Thurs mid 50s to mid 60s. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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VFR conditions continue this evening with breezy SW flow. Increasing clouds are expected during the overnight with mid and high cloud ceilings lowering to MVFR/IFR ceilings by early morning as a cold front approaches and moves through the region. As the backdoor cold front drops through the area, winds shift back to the N/NE as strong high pressure builds north of the region on Fri (doing so from 12-15Z (except again a little earlier at SBY). Will probably have a brief period of gusts to ~20 Kt all sites with the front, but overall winds on Fri will avg 10 Kt inland and ~15 Kt near the coast at ORF. MVFR to potentially IFR conditions may prevail for a few hrs Fri morning before conditions improve in the aftn. There is a higher potential for more significant flight restrictions on Sat, with some mixed precipitation possible by Sat morning over the N and mainly a chance for rain elsewhere. MVFR/IFR flight restrictions likely to persist into at least Sunday (and perhaps into Mon) as a frontal boundary lingers across the Carolinas and a NE low level flow prevails. Still a lot of clouds and unsettled Mon night/tue but should see a gradual improvement as flow shifts more to the S.
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&& .MARINE... SCA`s continue through the early evening for the gusty SW winds. Winds expected to go just below criteria tonight. Backdoor front drops south across the waters Fri morning. High res data in better agreement that a minimal SCA is possible over the Ches Bay from late Fri morning through the afternoon with the surge reaching the Currituck sound by late afternoon into Fri evening. Thus, will go ahead and hoist the headlines for Friday with this forecast package. Decided to hold off on any headline over the coastal waters given low confidence in wind gusts to 25 kts and/or 5 foot seas. Conditions may eventually get to criteria over the coastal waters due to the persistent NNE flow over the weekend. && .TIDES/COASTAL FLOODING... Latest storm surge guidance continues to indicate below normal tides into Fri ahead of the cold front. Tidal locations along the Atlantic coast...lower Ches Bay/James River can expect departures of -1.0 to -2.0 MLLW. Have extended the low water advisory for another tide cycle tonight. && .CLIMATE... Well above normal temperatures have occurred across the region today. Record maximum temperatures may be challenged... just a few days after setting several record lows. Records Max Temps for today, Jan 12: ------------- * Richmond: 71 (2005) *already 70F at 200 PM * Norfolk: 75 (1890) *already 72F at 300 PM * Salisbury, MD: 65 (1913) *already 67F at 300 PM * Elizabeth City, NC: 70 (2005) *already 72F at 300 PM * Wallops Island: 65 (1980) *already 70F at 200 PM && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ630>632-634>638. Low Water Advisory until 4 AM EST Friday for ANZ632-634-638- 650-652-654-656-658. Small Craft Advisory from 10 AM Friday to 3 AM EST Saturday for ANZ634. Small Craft Advisory from 10 AM to 7 PM EST Friday for ANZ630>632-638. Small Craft Advisory from 4 PM Friday to 3 AM EST Saturday for ANZ633. Small Craft Advisory until 5 AM EST Friday for ANZ650-652. && $$ SYNOPSIS...BMD NEAR TERM...BMD SHORT TERM...BMD LONG TERM...MPR AVIATION...LKB/JEF MARINE...MPR TIDES/COASTAL FLOODING... CLIMATE...

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