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fxus64 khun 172334 
afdhun

Area forecast discussion
National Weather Service Huntsville Alabama
634 PM CDT Thu Oct 17 2019

Update...
for 00z tafs.

&&

Near term...(tonight)
issued at 322 PM CDT Thu Oct 17 2019

Another cool evening is in store for the Tennessee Valley as high
pressure overhead continues to dominate our weather. Ideal
radiational cooling tonight with light winds and mostly clear skies
with the exception of some highs cirrus on the outer fringe of the
tropical system in Gulf. Overnight lows drop down into the upper 30s
to lower 40s. Temps will remain just slightly warm for widespread
frost tonight.

Short term...(friday through Saturday night)
issued at 322 PM CDT Thu Oct 17 2019

Slightly warmer on Friday with afternoon highs in the lower 70s as a
ridge over the central Continental U.S. Pushes eastward. Cloud cover will
increase as well as the tropical system over the Gulf of Mexico moves
northeast towards Alabama. Temperatures Friday night remain mild
compared to the last few nights as cloud cover blankets the area.
Expect overnight lows to drop into the lower 50s.

By Saturday, the tropical disturbance currently over the Gulf will
begin to impact the area. Model guidance continues to trend with a
more easterly track, which in turn keeps the bulk of the precip to
our south and east. In fact, GFS/NAM/CMC only have some light showers
in northeastern Alabama and only the European model (ecmwf) brings more widespread
heavier rain. Blended pops and quantitative precipitation forecast to this eastern solution and hence
lowered rainfall totals compared to previous model guidance. Rain
ends from west to east overnight Saturday.

Long term...(sunday through wednesday)
issued at 322 PM CDT Thu Oct 17 2019

A consensus of guidance from the global models indicates that zonal
flow aloft will be in place across the region on Sunday, and with no
evidence of any passing mid-level disturbances to enhance lift, we
will keep the forecast dry. As early morning cloud cover dissipates,
temperatures should warm efficiently during the afternoon, likely
reaching the u70s-l80s.

It still appears as if deep-layer flow will back to the southwest
and strengthen considerably by Sunday evening, as a 500-mb shortwave
disturbance spreading eastward across the northern plains on Sunday
begins to deepen into a negatively-tilted trough over the Red River
valley region of the eastern Dakotas/western Minnesota. Winds aloft across
the Tennessee Valley will continue to strengthen and veer to the west-
southwest on Monday/Monday night as the primary synoptic trough
deepens further, eventually resulting in the development of a broad
longwave trough positioned over the central Continental U.S. By 12z Tuesday. At
the surface, southeasterly return flow will slowly become established
during the day on Sunday, but should increase further from Sunday
night into Monday, as a cold front attached to the trough's surface
low pushes east-southeastward toward the region. Although there is
still some uncertainty regarding the arrival time of the cold front
in the northwest portion of our forecast area, guidance is coming
into better agreement that this will occur late Monday afternoon,
with the front expected to exit the southeastern counties late Monday
evening. A band of convection will likely precede the passage of the
cold front, with scattered-numerous showers and thunderstorms also
expected to develop in the increasingly moist warm sector airmass
immediately ahead of the front, as well. The anticipated magnitude of
both deep-layer and low-level shear will support a risk of strong-
severe thunderstorms during this period, especially if boundary layer
dewpoints recover into the mid 60s, as advertised by most guidance.
However, abundant low cloud cover for much of the day will likely
reduce instability, and this may limit the overall threat for severe
convection to some degree.

Precipitation will end from northwest-southeast fairly rapidly in
the wake of the cold front Monday evening, as a dry/modified North
Pacific airmass is advected southeastward into the region. Moderately
strong west-northwest flow at the surface will provide just enough
cold air advection to keep Max temperatures in the M-u 60s on Tuesday, with abundant
sunshine and diminishing flow/advection resulting in slightly warmer
temps on Wednesday. Lows on Tuesday night should fall into the u30s-
l40s, with conditions expected to be favorable for radiational
cooling.

&&

Aviation...(for the 00z tafs through 00z Friday evening)
issued at 634 PM CDT Thu Oct 17 2019

VFR flight conditions will persist through the taf period at both
terminal locations. Northerly winds will begin to veer to the east by
Friday afternoon, and are expected to remain below 10 kts. Clear or
mostly clear skies should persist into Friday afternoon, but clouds
may begin to increase late in the day.

&&

Hun watches/warnings/advisories...
Alabama...none.
Tennessee...none.
&&

$$

Near term...gh
short term...gh
long term...70/dd
aviation...25

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