Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 140200

Area Forecast Discussion
National Weather Service Memphis TN
900 PM CDT Tue Apr 13 2021

Current forecast is on changes made.


.PREV DISCUSSION... /issued 616 PM CDT Tue Apr 13 2021/

DISCUSSION... Complex upper pattern will prevail through the
weekend, resulting in cooler than normal temperatures and a couple
rain events, Wednesday and Friday night.

Over the past several days, two large upper lows have remained
nearly stationary over the Pacific northwest and the upper
Midwest/western Great Lakes, while largely zonal flow prevailed
across the southern half of the CONUS and the Midsouth. Despite
the zonal flow, a continental polar airmass edged southward into
the Midsouth today, losing its push over northeast MS. Midafternoon
temps ranged from the mid 60s in northeast AR to the lower 80s
over northeast MS.

Showers will again develop Wednesday, associated with a shortwave
lifting out of TX. Warm advection will develop late tonight in
advance of the approaching wave. Model soundings show modest
elevated instability at best, suggestive of a few lightning
strikes over north MS Wednesday morning. Otherwise, showers are
expected, most numerous along and south of I-40, before the wave
exits Wednesday afternoon. The stationary front over northeast MS
will finally push south Wednesday afternoon, behind the exiting

Fair weather will prevail Thursday, downstream from an upper
ridge over plains. Afternoon humidity levels will drop below 30
percent in over northeast MS and west TN. Fire weather concerns
should be alleviated by prior rainfall and gradually weakening
winds in the afternoon.

Out west, an upper low will drop into the central high plains by
early Friday. Downstream diffluent flow will develop over a low
level moisture axis across TX and the southern plains. Medium
range models were in good agreement depicting an ejecting
negatively-tilted shortwave across the Ozarks Friday evening,
phased with a weaker southern branch wave along the gulf coast.
Showers will spread into the Midsouth late Friday afternoon, with
some thunder not out of the question Friday evening. The phased
shortwaves will exit late Friday night, followed by a reinforcing
cold frontal passage Saturday morning. Another northern branch
upper low will drop into the mid- MS River valley Sunday, before
exiting through the Ohio River valley Sunday night. Implications
for the Midsouth: continued cooler than normal temps through the
weekend and early next week. ECMWF model even depicts 537 dm
1000-500mb thickness over northwest TN late Sunday night. Cooler
temps indeed.


/00z TAFs/

CIGs will lower by tomorrow morning as showers move into the area.
Expect MVFR to IFR CIGs by tomorrow afternoon. Winds will be
north/northeast at 7 to 10 kts.




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