Area forecast discussion
National Weather Service Wakefield Virginia
656 PM EDT Wednesday may 22 2013
Synopsis...
the combination of high pressure over the Atlantic and southwest
winds will continue to pull a warm and humid airmass into the region
through Thursday. A cold front will pass through the middle Atlantic
Thursday night into Friday morning. High pressure returns to the
area late Friday into the weekend with drier conditions and cooler
temperatures expected.
&&
Near term /until 6 am Thursday morning/...
update...isolated showers have ended across far southeast Virginia and NE NC
this evening. Stray showers are possible in the eastern Piedmont from
roughly Farmville to Louisa...however predominant southerly winds
should keep the bulk of shower and thunderstorm activity farther
west and out of the forecast area for the remainder of this evening.
Previous discussion...mainly dry conds for the overnight hours. Temperatures
remain well above normal tonight as southerly flow persists...lows in
the upper 60s under a prtly to mostly cloudy sky. Patchy fog is
possible but more in the way of low stratus is expected. Chances for
rain will increase Thursday morng as moisture and middle-level energy
embedded in the SW flow aloft increases.
&&
Short term /6 am Thursday morning through Saturday/...
chances for rain will increase through the day Thursday as deep layer moisture
increases and low pressure approaches from the west. Not expecting
widespread severe weather however an isolated damaging Wing gust is possible as
shear profiles increase ahead of an approaching middle-level trough.
Don't expect it to rain the entire day however coverage is enough to
warrant likely (70%) probability of precipitation. Best timing for heavy rain will be in
the afternoon/Erly evening hours as moisture increases and the middle Atlantic
sits under the right entrance region of an upper-level jet streak. Hi
temperatures genrly in the low 80s. Readings will be a bit cooler near the
coast. The rain will end from west to east Erly Friday as the cold
front advances off the coast. Not expecting skies to completely clear
out...with moisture still in place aloft following the surface frontal passage.
Drier conds expected by Friday afternoon (though keeping a chance for showers
over eastern areas with the upper-level trough still west of the area) as
surface flow becomes nwrly for the first time in several days...and
temperatures only reaching the low to middle 70s in most locations. Surface hi
pressure builds in from the west on Sat leading to a mostly sny sky and
noticeably cooler temperatures (highs only in the low to middle 70s).
&&
Long term /Saturday night through Wednesday/...
medium range forecast period characterized by modified Canadian high
pressure dropping northwest to southeast across the area for the latter half of
the Memorial Day weekend. Aloft, closed upper level low over the
northeast and Atlantic Canada will slowly lift NE Sunday, allowing
for modest height rises aloft, and with it a general incremental
ramping up of temperatures through the period. It will also allow for
northwest flow aloft across the southern middle-Atlantic Sunday and
Monday. Low (slight chance) probability of precipitation remain in place for Memorial Day
afternoon/evening as a weak disturbance/middle level trough drops across
the region and a surface warm front lifts north to the west.
Bermuda high/Summer-like pattern reloads for the middle to latter
potion of the week, as middle-upper level ridging rebuilds across
the eastern half of the Continental U.S. And surface high slides offshore. Rainfall
opportunities will primarily be diurnally driven Monday-Wed, with
little more than partly cloudy and increasingly muggy conditions
by night.
&&
Aviation /00z Thursday through Monday/...
scattered-broken cumulus / SC around 3k feet continues through 00z. Went with a tempo group
for thunderstorms and rain next few hours based on current radar trends of scattered convection
dvlpng across NE NC. Gusty S-SW winds up to 20 knots.
Latest tsctns show plnty of low level moisture around aftr 04z for a stratus
deck to develop once again. Data even suggests some dense fog ivof sby
late tonite. Otw...patchy MVFR fog possible.
Slow liftg of the cloud deck Thursday morning. Cdfrnt apprchs from the
west drng the afternoon with precipitation assctd with this ftr holds off until
aftr 18z...so kept precipitation out of forecast for now.
Outlook: front pushes off the CST during Friday...with lagging upper
trough not moving offshr until late Friday night. So...there could be
lingering lower ceilings and visibilities from scattered precipitation right through Friday night. VFR
conditions return for Sat and sun...as hi pressure builds into and over
the region.
&&
Marine...
Small Craft Advisory for the ches Bay has been discontinued as per latest observation.
However, have hoisted Small Craft Advisory for late tonight through early Friday as
winds /waves/seas slowly ramp up as pressure gradient tightens
between Bermuda high and approaching cold front to the west.
As gradient continues to tighten, guidance continues to show seas
ramping upward into Small Craft Advisory range over southern coastal waters late
tomorrow afternoon and evening. Will not hoist the headline just
yet, but an additional Small Craft Advisory headline will likely be needed south of
Cape Charles after 18z tomorrow.
Front will cross the waters late Thursday night/early Friday through Friday
afternoon...with a strong north-northwest surge of winds (~20 knots and gusty)
expected Friday through early Saturday. Small Craft Advisory flags are likely to be
needed through this period, with conditions to become sub-Small Craft Advisory with
winds diminishing at or below 15kt Sat afternoon through Monday as high pressure
builds across the waters over the Holiday weekend.
&&
Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory until midnight EDT Thursday night for
anz630>632-634-650-652-654.
&&
$$
Synopsis...bmd/mas
near term...bmd/mas
short term...mas
long term...mam
aviation...mpr
marine...mam
