NEAR TERM [Through Tonight]...
Light rain developing around area. Updated aftn for low chances
over land. Updated QPF/WX grids.
The large scale split flow long wave pattern remains highly
amplified especially across Srn stream. This is highlighted in Nrn
stream by ridging over Wrn states, trough over Great Lakes to east
coast and ridging into adjacent Atlc. Srn stream highlighted by deep
trough over Srn plains with closed low over NRN old Mex and Srn TX
and by ridging over se region into Wrn Atlc.
At surface, analysis shows a low near TX with cold front swd into
WRN most Gulf, and W-E quasi-stnry warm front extending Ewd across
coastal Gulf FL counties. Warm front has lifted from adjacent waters
to over srn most coastal counties since this morning. It remains
well defined, increasingly separating a moist tropical airmass over
the Nrn Gulf from a modified continental one that has been in place
across the SE. Dew points just S of front in the mid 60s. This front
was also responsible for generating area of fog, low stratus,
sprinkles and drizzle along and north of it across our land area
especially before midday. During the late morning into early aftn,
some breaks in overcast plus erosion of clouds from W-E allowed some
lessening of rain and modest raising of cloud heights.
Into tonight, NRN stream trough will move quickly across Great Lakes
region then Ewd towards NE states in response to next trough that
begins to dig SEWD across extreme Ern PAC into West coast. TX low
will shift NEWD across rest of TX (and eventually into Lwr MS
Valley) generating widespread convection. In response, SE ridge
builds NWD. The combination of NRN trough and lifting TX low will
accelerate cold front across TX and lift warm front NWD, However
main forcing will remain well to our west in the vicinity of cold
NAM keeps high pops especially Wrn half of CWA, however this
contradicts, GFS, CAM ,WRF and local confidence tool which keeps the
rain to our west showing only wdly sct light rain/sprinkles/drizzle
except for possible low sct rain Wrn most counties. Will discount
MET and go with 20% light rain except for possibly Ern most waters.
Abundant clouds will keep temps mild. Went guidance concensus which
leans towards miler night so lows generally around 60. The main
concern is fog. With the warm front lifting northward through the
area, the region will be in an increasingly more humid airmass. Warm
and moist onshore flow moving over cooler shelf waters of Gulf will
likely continue to generate sea fog over the marine area and
adjacent coast. This is evident in the local NAM DNG5, SREF other
guidance and satellite pix which are unusually bullish of waters.
This will compliment radiation fog over land. All this reflected in
latest GRIDS and next shift may need to go with a dense fog advisory
(over land and water) that will last well beyond sunrise.