320
FXUS64 KJAN 210505 AAB
AFDJAN
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1105 PM CST Wed Nov 20 2024
...New AVIATION...
.MESOSCALE UPDATE...
Issued at 949 PM CST Wed Nov 20 2024
Clear skies and a very light wind should lead to strong
radiational cooling of our cool dry airmass. Temperatures have
already dropped into the lower 40s in spots. Forecast minimum
temperatures look on track to bottom out in the 30s at most
locations. No changes were needed to with forecast. /22/
&&
.DISCUSSION...
Issued at 312 PM CST Wed Nov 20 2024
Tonight through mid next week (Wednesday)...
Through this weekend(Tonight-Sunday): Stout cold core trough is
progged to continue to swing to the east across the MS River
Valley to OH Valley, with a sfc low occluding over the Great
Lakes. At the sfc further south, high pressure & continued
northwesterly flow will persist as 1030mb high sags southeastward
out of south-central Canada into the northern Plains & southwards
into the Plains. Between the two features, the sfc cyclone will
retrograde westward across the Great Lakes before diving east-
southeast into the OH Valley to northeast states. This will keep
broad northwesterly flow & tight gradient across the region,
gradually relaxing from nearly 5- 6mb today to only around 3mb by
Friday. This will help winds gradually to relax into late week,
but some persistent gradient wind to exist around the area. For
sensible weather elements, this supports near to slightly
seasonably cool highs Thursday & especially Friday, some 5F below,
in the 60-66F range Thursday & 54- 60F range Friday. Lows will be
seasonably cool both nights, some 4- 6F below, in the 36-40F
range tonight & 33-38F Friday night. Due to some wind around,
frost/freeze potential will be somewhat mitigated Thursday night.
However, if gradient can relax some, this could support some
patchy frost in the I-55, Hwy 25 to Hwy 82 corridor Friday
morning. Added a "Limited" in the HWO to account for this. The
more widespread frost/freeze potential will be Friday night as
1020mb sfc high builds southeast into the ArkLaTex to Gulf Coast
states. This will support light to decoupling sfc winds & lows
falling near to below freezing. There remains variability in the
operational blended guidance being the outlier but gradually
catching up on colder temps. Probabilistic guidance is more
narrowed, with 40-70% of reaching
NWS JAN Office Area Forecast Discussion
Mt Washington Wx CAM
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