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Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
402 am EDT sun Jun 16 2019

a cold front will approach the area from the north today. The
front will stall out nearby on Monday and remain nearly
stationary across the area through the middle of next week. It
may finally shift southeast of the region by Saturday.


Near term /through tonight/...
a very warm and humid air mass will be in place today coupled
with a Lee-side trof and weak 500 mb wave will aid in T-storm
development this afternoon. Mid-level flow will be relatively
strong with 40kt at 500mb contributing to 30-40kt of 0-6km bulk
shear. A few severe T- storms are expected late this afternoon
through late this evening. Northern and central Maryland appears
to be at greatest risk of severe thunderstorms with T-storm
coverage decreasing markedly south of I-66. Damaging wind gusts
appear to be the biggest threat given the moderately strong flow
aloft and fast storm motions (~ 30kt). The severe wx threat
should wane after 10pm or so, but risk of T- storms will likely
persist well into the overnight hours.


Short term /Monday through Tuesday night/...
Monday still appears as it will be the most active day this
week with a slow moving front nearby and ripples of upper level
energy aiding in T-storm formation. Shear and storm motions will
be weaker suggesting an increased flash flood threat especially
given mid- level flow becoming parallel to sfc front which will
also favor training. Cape values, on the other hand, are
expected to be much higher than on Sunday, which also support a
severe wx and flash flood threat. A Flash Flood Watch may be
issued for some areas at this time tomorrow once confidence in
location of T-storms increases. Simulated satellite imagery from
various global models indicate convection will be more
widespread and intense than today.


Long term /Wednesday through Saturday/...
Wednesday and Thursday will continue the pattern of previous
days, as a stalled front will remain in the region just to our
north. High pressure over the western Atlantic will continue to
funnel warm, humid air northward into the region, and
disturbances will continue crossing the region. This combination
will result in repeated rounds of showers and thunderstorms,
some of which may produce torrential rain and gusty winds.

Uncertainty exists Friday, with some recent models like the
European model (ecmwf) sending a stronger wave through and pushing the front
south of the region faster, while the ggem and GFS are slower
and linger the front on Friday before finally pushing dry
Canadian high pressure southward into the region Saturday. By
Saturday, the Canadian high pressure should dominate, with a
better risk of dry weather. This should also result in somewhat
lower temperatures and markedly lower humidity.


Aviation /08z Sunday through Thursday/...
T-storms likely this afternoon and through Tuesday. Gusty winds
and heavy threat possible with any T-storms.

VFR cigs/vis should prevail Wednesday and Thursday. However,
typical Summer conditions will lead to typical Summer problems.
Patchy early morning mist/fog may result in reduced vis,
especially at the more rural terminals. Scattered thunderstorms,
primarily during the afternoon and evening hours, may result in
reduced vis, low cigs, and gusty widns.


T-storms likely this afternoon and through Tuesday. Gusty winds
and heavy threat possible with any T-storms.

Winds will generally remain below Small Craft Advisory criteria Wednesday and
Thursday with a stationary front in the area keeping the
gradient weak. However, scattered showers and thunderstorms may
produce gusty winds, resulting in potential special marine
warnings both days.


Lwx watches/warnings/advisories...
District of Columbia...none.
Marine...Small Craft Advisory until 6 PM EDT this evening for
Small Craft Advisory from 11 am this morning to 6 PM EDT this
evening for anz535.



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