Area Forecast Discussion
Issued by NWS Sterling, 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 270130 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 830 PM EST Sat Nov 26 2016 .SYNOPSIS... High pressure will move across the region through Sunday, then move offshore on Monday, ushering in southerly winds and warmer temperatures. A storm system will begin to approach the region on Tuesday, but the associated cold front will not move through until Wednesday or Wednesday night. && .NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
High pressure will continue to approach from the Midwest overnight. A northwest flow will usher in dry and chilly conditions with min temps ranging from the 20s in the mountains to the lower and middle 30s near Washington and Baltimore. For Sunday, high pressure and dry air will result in just a few clouds and an increasingly less breezy day. Temperatures will be fairly similar to today, but with less wind it will feel a little less chilly.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... Sunday night will be the coldest of the upcoming stretch, with high pressure allowing for fairly widespread decoupling of the winds. Lows mainly in the 20s except in the usual warm spots (and on ridgetops). Clouds increase Monday. There is a bit of model disagreement on temperatures. The consensus shows southerly flow by afternoon, but the GFS doesn`t have it at all, and therefore is cooler. Will stick with the consensus for now. The previous forecast seems to have a good handle on the precip onset Monday night. Of note, it looks like a good chance temperatures will warm at least for the second half of the night, so no precip type issues like we sometimes have at onset. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A warm front will lift north across the region Tuesday morning, followed by a cold front moving northwest to southeast Tuesday evening. A persistent southerly flow will fuel rain showers throughout the day Tuesday. As the cold front slides across southern Maryland and east- central Virginia Tuesday evening, there could be a brief break in the rain shower activity into the overnight hours. A second storm system is expected to develop along the tail-end of the cold front over the interior Southeast U.S. Wednesday morning. The storm should ride northeast along the front Wednesday and Wednesday night, bringing more rain showers to the region. The storm system will continue to move northeastward toward southern New England Thursday. High pressure will build in behind the storm and its associated cold front Thursday and Thursday night. Drier and colder air will filter into the region. An upper level trough of low pressure is expected to sag southward into the region from the Eastern Great Lakes Thursday night and Friday. There may not be a lot of moisture available to fuel any showers with the trough. Plus, a downsloping flow over the Appalachian Mountains could encourage a dry day Friday. High pressure will build in behind the trough of low pressure Friday night and Saturday. Dry and chilly conditions expected. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Drier air on a northwest flow will allow for clouds to diminish tonight. Northwest winds around 5 to 10 knots are expected overnight...but there could few more gusts around 20 knots Sunday. VFR conditions expected through Monday. Outlook... Conditions will quickly deteriorate to IFR or even LIFR as precip onset occurs late Monday night or early Tuesday. Rain showers expected through the day with gusty southerly winds. Low clouds hang in for Tuesday night and a second round of showers Wednesday. Could be yet a third round of showers and low ceilings either Wednesday night or Thursday morning before drying and clearing occur.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
A Small Craft Advisory remains in effect for the Maryland Chesapeake Bay and the lower Tidal Potomac River. However...it will be marginal across the inlets as well as the Maryland Chesapeake Bay north of Pooles Island. Winds may increase for a period Sunday due to a deepening mixing layer. A Small Craft Advisory is in effect for the waters. However...the wind field will subside Sunday afternoon and the Small Craft Advisory may be cancelled early. No marine concerns Sunday night through Monday night. Small craft advisories likely Tuesday with winds southerly 15 to 20 knots and higher gusts. Channeling may lead to gale force gusts on Tuesday. Small craft advisory conditions are possible Tuesday evening. Winds southerly 10 to 15 knots with higher gusts Tuesday night. May be a second round of southerly channeling up the bay on Wednesday.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING...
-- Changed Discussion --
Water levels are dropping below normal. We could approach a foot below normal tides before winds shift on Monday and the anomaly starts to rebuild. The southerly channeling favors elevated water levels, but our model output is not handling it very well this far out. Bottom line is that minor coastal flooding is possible along the bay Tuesday/Wednesday but uncertainty is high.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 PM EST Sunday for ANZ530>534- 536>543. Small Craft Advisory from 6 AM to 6 PM EST Sunday for ANZ535.
-- End Changed Discussion --
&& $$ SYNOPSIS...JCE NEAR TERM...JCE/BJL SHORT TERM...JCE LONG TERM...KLW AVIATION...JCE/BJL/KLW MARINE...JCE/BJL/KLW TIDES/COASTAL FLOODING...JCE

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