FXUS64 KBMX 192320
Area Forecast Discussion
National Weather Service Birmingham AL
620 PM CDT Mon Aug 19 2019
For 00Z Aviation.
/Updated at 0320 PM CDT Mon Aug 19 2019/
With increased moisture and a weak shortwave over the area,
storm coverage has been higher this afternoon than this past
weekend. While the added cloud cover and rain kept temperatures
and heat indices in check at some locations, heat indices have
reached over 105F in others. At 3PM, many locations are reporting
heat indices above 100F.
Main area of convection will be across the west and extreme
northeast for the next couple hours, as activity is becoming
mainly outflow driven. Coverage will decrease this evening, but
will need to watch clusters of storms in northern Georgia and
southwest Georgia as they move to the southwest and west this
evening. Expect all activity to diminish late tonight, with lows
in the low to mid 70s.
/Updated at 0356 AM CDT Mon Aug 19 2019/
Tuesday through Sunday.
Much of the extended forecast remains on track for this update. On
Tuesday, high pressure sits over the eastern Plains while a large
anticyclone remains over the western Atlantic. In between these two
circulations, a weak low-level inverted trough and low height center
will situate over portions of the Southeast including southern
Georgia and the Florida Panhandle as southeasterly anticyclonic flow
aloft shifts the disturbance slowly westward over the forecast area
through Wednesday. This feature will provide support for afternoon
convection as we begin to see lower temperatures with highs
decreasing into the low to mid 90s, although higher humidity levels
will make it feel a bit warmer. The overall wind and height fields
become rather messy on Thursday with the aforementioned weak
troughing becoming much less defined, but with the Bermuda High
extending to our southeast, a few periods of southerly low-level
winds appear likely enough to continue fueling a moist airmass
such that scattered to numerous afternoon thunderstorms can be
expected during peak heating on Thursday and Friday.
Meanwhile, deep-layer troughing deepens over the eastern CONUS by
the end of the week driving a cold front south through the Ohio and
Tennessee Valleys. Uncertainty remains between model guidance on
whether the tail edge of the front will ultimately pass through the
forecast area this weekend, and confidence remains low on any one
given outcome. Therefore, the forecast for Saturday and Sunday, and
associated 50 to 60 percent PoPs, will be focused on the broad
cyclonic flow aloft over Central Alabama as the base of the trough
moves through the southeast in conjunction with a rich axis of
moisture (PWATS ~2 inches) ahead of the front. Periods of rain over
the next week will help keep us cooler during the daytime with
highs in the upper 80s to near 90F Saturday and Sunday as ridging
becomes less pronounced over the forecast area.
00Z TAF Discussion.
TSRA will impact KEET and KMGM thru 01z. Convection will under a
decaying trend due to loss of daytime heating. VFR conds expected
thru the period, with the exception of lower vsbys associated with
heavy rainfall from thunderstorms. MVFR vsbys may also develop
between 08z and 12z at KMGM and KTOI where the air mass has
cooled from afternoon storms. Similar set-up on Tuesday with Sct
TSRA developing in the afternoon.
Increased rain chances continue each day this week, with scattered
to numerous mainly afternoon showers and thunderstorms. Localized
fog is possible each morning, but locations will vary depending on
the previous day's rain coverage. Temperatures will gradually
return to normal levels by mid week as relative humidity values
continue to rise.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 70 96 71 94 70 / 20 40 20 40 30
Anniston 71 95 72 94 71 / 30 40 30 40 30
Birmingham 73 97 74 96 73 / 30 40 30 40 30
Tuscaloosa 74 96 74 95 73 / 30 40 30 40 30
Calera 71 96 72 94 71 / 30 40 30 40 30
Auburn 72 91 72 91 72 / 40 50 30 50 30
Montgomery 73 95 73 94 73 / 40 50 30 50 30
Troy 71 92 71 92 70 / 40 60 30 50 20
Heat Advisory until 9 PM CDT this evening for the following
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