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Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
256 PM EDT Wed Oct 23 2019

high pressure will continue to build into the region through
Thursday, before shifting offshore on Friday. A dry cold front will
push through the area late Friday. Low pressure will form along the
southern end of this boundary in the lower Mississippi River valley
early Saturday, before tracking to our west Saturday night into
Sunday. The cold front associated with this system will push through
early Sunday. Another low pressure system is possible early next


Near term /through tonight/...
high pressure continues to build into our region from the southwest.
Clear skies with some gusty westerly winds are observed today behind
the front. Winds will be on the decrease this evening as high
pressure approaches our area.

High pressure will build overhead tonight bringing light winds and
clear skies allowing for a radiational cooling set up. Have leaned
towards the cooler side of guidance, expecting temperatures to reach
the mid 30s in most locations west of I-95... maybe a few low 30s
and upper 20s at some locations over the Potomac Highlands and
central Shenandoah Valley. A frost advisory has been issued for
late tonight over the counties where the growing season


Short term /Thursday through Thursday night/...
high pressure will be overhead early on Thursday as it moves
east and offshore the mid-Atlantic coast on Thursday night. Dry
weather and seasonable conditions will continue during this
time along with light winds. High temperatures will be in the
mid to upper 60s, with lower temperatures at the ridges. Low
temperatures will be in the upper 30s to mid 40s.


Long term /Friday through Wednesday/...
on Friday things will remain dry across the region, with
seasonable temperatures in the mid 60s, as a dry cold front
pushes through the region late in the day into Friday night.

A large deep upper trough will move across the central U.S. On
Friday as well, with an area of upper-level low pressure cutting off
from the main trough axis across the Southern Plains. Model guidance
has finally come to agreement on this fact, but there is still some
uncertainty as far as the speed of this system, and when it will
impact our area. Surface low pressure will form over the lower
Mississippi River valley Friday night into Saturday, as this upper
low interacts with the southern end of the aforementioned cold
front. Then another trough will swing in out of the Pacific northwest
throughout the day on Saturday, bringing the cutoff low to the North
East, towards our area. This will result in the surface low
following a similar track, and likely passing by to our west.
Guidance seems to be converging on timing for the most part, but
still some disagreement on when we see precipitation associated with
the warm front. The GFS brings this precip in earlier in the day on
Saturday, while the European model (ecmwf) brings it in Saturday evening. However, it
appears as though the main core of precipitation associated with the
cold front will push through Sunday morning, before clearing out by
late Sunday afternoon. High temperatures on Saturday and Sunday will
be in the low to mid 60s, with Sunday seemingly being the warmer of
the two.

Dry conditions Sunday night through the early part of the day on
Monday, as high pressure slides by to the north. However, some
uncertainty comes into play as we get into Monday afternoon. Most
guidance keeps US dry, however the GFS wants to stall the front and
bring a weak area of low pressure along it Monday afternoon/evening,
resulting in another round of rain. Given that it is the outlier
here, going with lower end pops for this potential at this time, but
Worth noting.


Aviation /Wednesday through Monday/...
gusty westerly winds will diminish this evening as high pressure
builds into our area. High pressure will build overhead tonight and
into tomorrow before starting to move offshore Thursday night.
VFR conditions should prevail through Thursday night with light
winds. Possible restrictions due to fog late Thursday night.

VFR conditions expected Friday through the first half of Saturday.
However, beyond that, rain becomes a possibility as we head into
Saturday afternoon/evening. Timing of the onset is a bit uncertain,
but the main core of rainfall will move through Saturday night into
Sunday morning. This will be the most likely period for visb
restrictions. Low cigs also likely with frontal passage.


gusty winds at or just below criteria are observed this afternoon
over the waters. A Small Craft Advisory is in effect through this afternoon. Winds
will diminish this evening and become light tonight into Thursday
night as high pressure builds overhead.

Generally expecting calm winds Friday through the first half of
Saturday, with high pressure gradually pushing offshore. Low
pressure will be approaching the area from the southwest, and slide
by to our west Saturday evening into Sunday. Could see some gusty
winds associated with this system late Saturday into Sunday, but not
expecting Small Craft Advisory criteria winds at this time, but it could come very
close. Winds will die down again into Sunday evening.


Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...frost advisory from midnight tonight to 9 am EDT Thursday for
Virginia...frost advisory from midnight tonight to 9 am EDT Thursday for
Marine...Small Craft Advisory until 4 PM EDT this afternoon for
Small Craft Advisory until 6 PM EDT this evening for anz530-


near term...imr

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