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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS64 KHUN 160442
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1142 PM CDT Sun Sep 15 2019

.UPDATE...
-- Changed Discussion --
For 06Z TAFS.
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&&

.NEAR TERM...
-- Changed Discussion --
(Rest of tonight)
Issued at 918 PM CDT Sun Sep 15 2019

Despite a warm afternoon with highs reaching the 93 to 97 degree range
in most locations, temperatures under clear skies and calm winds have
dropped into the low to upper 70s already at 8 PM. Dewpoints west of
I-65 are remaining in the upper 60s to around 70 degrees at this hour.
Further east, dewpoints are in the mid to upper 60s. With clear skies
and light winds expected the remainder of the night, optimal radiation
cooling should continue. This looks to set the stage for some patchy
fog development after midnight in northwestern Alabama in particular.
Further east, models show low level flow from the northeast or east
advecting drier air into north central and northeastern Alabama overnight.
This drier air should keep fog from forming just east of the I-65 corridor
into northeastern Alabama through daybreak.

Tweaked dewpoints and temperatures lower after midnight. Think that
some fairly widespread lows in the lower 60s look possible east of
I-65. This may not even be cool enough, as some upstream observations
have dewpoints in the mid to upper 50s. Otherwise, no changes made to
the previous forecast.

.SHORT TERM...(Monday through Wednesday)
Issued at 250 PM CDT Sun Sep 15 2019

Above normal temperatures will continue through the middle of the
work week, as the aforementioned H5 ridge continues amplifying and
slowly sliding east. The good news is that while highs will be in the
low to mid 90s through mid-week, dew point temps will struggle to
reach the middle 60s on Monday, and only climb a few degrees more on
Tuesday and Wednesday as slightly better low level moisture streams
down into the Valley. Expect clear to mostly clear skies on Monday,
and an increase in cu Tuesday and Wednesday. Have kept a dry forecast
through the short term period, given subsidence and the lack of any
real forcing to support shower and storm development. Overnight lows
will be in the upper 60s to near 70 degrees. Northerly winds will
remain on the lighter side through Wednesday.

.LONG TERM...(Wednesday night through Saturday)
Issued at 250 PM CDT Sun Sep 15 2019

Big picture forecast for the extended continues dry conditions, with
warmer than normal temperatures. Despite a more active northern
stream bringing a series of systems over the Pacific NW, and more
generalized troughing occurring over the western third of the
lower-48, upper ridging will overall maintain itself over the
southern states. The existence of this ridging and high pressure over
the SE CONUS will continue a string of very warm to hot days (for
middle September) and little to no chance of rain.

At the beginning of the extended, tropical system Humberto (probably
a hurricane at this time) should be located well off of the GA/FL
coast, passing dangerously close to Bermuda during Thursday. High
pressure otherwise will build southward from the NE CONUS, continuing
a warmer than normal trend. One item of interest was the GFS (and to
a lesser extent the Canadian), hinting at light shower possibilities
on Thursday as a weak boundary traverses the region. Given the dry
trend already going, opted dry during this period. One change from
Thu into the weekend should be a slight cooler trend. From high
temperatures in the mid 90s into the midweek, highs there after
should range in the upper 80s to lower 90s. Normal high/low
temperatures by next Sunday for reference (the last day of summer
2019) are around 83/60 -- with forecasts of 92/64.
-- End Changed Discussion --

&&

.AVIATION...
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(For the 06Z TAFS through 06Z Monday night)
Issued at 1006 PM CDT Sun Sep 15 2019

No changes from previous forecast thoughts.

Light winds and clear skies later this evening and overnight are expected.
Slightly more moist air should remain in place near the KMSL terminal.
Coupled with good radiational cooling conditions, think that some brief
patchy fog dropping VSBYS to MVFR conditions is possible after 09Z
at KMSL. However, with drier air in place at KHSV, leaving MVFR
reductions out of the forecast. Otherwise, VFR conditions are
expected at both terminals after 14Z with winds becoming more
northeasterly around 5 knots.
-- End Changed Discussion --

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

NEAR TERM...KTW
SHORT TERM...25
LONG TERM...RSB
AVIATION...KTW


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