Area Forecast Discussion
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FXUS62 KTAE 211707

Area Forecast Discussion
National Weather Service Tallahassee FL
107 PM EDT Sat Oct 21 2017

.AVIATION [Through 18Z Sunday]...

VFR conditions will prevail for the most part. We will see a
scattered cumulus deck at 4-6 kft this afternoon dissipate
overnight. Most guidance indicates an MVFR deck moving in from
the east during the pre-dawn hours and we have shown this for ABY
and VLD. Winds will be out of the east, generally 10 kt or less.



.NEAR TERM [Through Today]...

The upper level ridge axis is well east of us now and that has
allow a lot of cirrus to spill over the top of the ridge into the
forecast area. We upped cloud cover just a bit to reflect this,
but there will be plenty of sunshine filtering through those
clouds. Afternoon highs will be similar to yesterday with mid 80s
common. That`s about 5 degrees above normal.

.SHORT TERM [Tonight Through Monday]...

A vigorous deep-layer trough will approach our forecast area from
the west. At 500 mb, the base of this trough will become
temporarily separated from the mid latitude westerlies Sunday
night and Monday, while a corresponding surface cyclone develops
over southwest AL and tracks northward to eastern TN by Monday
evening. Ample deep-layer moisture, coupled with strong Q-G
forcing, make rain all but a certainty on Monday, though PoPs (in
the 20-30% range) will begin as early as Sunday afternoon.
Forecast shear values suggest the potential for organized severe
storms, including rotating updrafts. However, buoyancy may be
rather weak given the expected cloud cover and wide coverage of
rain, and it remains unclear how significant the threat of severe
storms will be. Should severe storms develop, the main threat
would be damaging wind gusts and isolated tornadoes.

Temperatures will be mostly above average as our forecast area
enters into a period of warm/moist advection. Lows will be in the
60s tonight, and in the 70s Sunday night. Highs will be in the mid
80s Sunday, but "only" near 80 on Monday due to the clouds and

.LONG TERM [Monday Night Through Saturday]...

The latest global NWP models are in good agreement in developing a
sharp mid-layer dry slot over our region Monday evening, bringing a
rapid end to the rain from west to east. Fair weather and genuinely
cooler temperatures are in store for the remainder of the work week,
followed by increasing rain chances next weekend ahead of the next
trough approaching from the west. Lows will be in the 45 to 50
range Tuesday night through Thursday night. Highs will struggle
to reach 70 on Wednesday (despite ample sun), and will remain in
the 70s through the work week.


With a relatively strong high pressure system continuing northeast
of the marine area, east winds of 15 to 20 knots will persist through
Sunday, with seas 3 to 6 feet. Winds will veer to the south
Sunday night and Monday as a cold front approaches from the west.
Winds will shift to the west behind the cold front Monday night,
but remain in the 15 to 20 knots range.


High dispersion values above 75 are likely today. A wetting rain
is likely Monday as a cold front moves through the region. Dry air
will move in midweek but RH values will not be low enough to
prompt a Red Flag Warning.


The greatest chance for heavy rain will be Monday, with widespread
QPF amounts of 1 to 2 inches, and isolated amounts up 3 inches.
This is unlikely to cause widespread flooding.


Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.



Tallahassee   86  66  86  73  81 /   0   0  20  40  90
Panama City   84  69  84  75  80 /   0   0  20  60  90
Dothan        84  63  86  71  77 /   0   0  10  60  90
Albany        85  63  86  71  80 /   0  10  10  30  90
Valdosta      84  65  86  71  81 /   0  10  20  20  80
Cross City    86  66  87  72  83 /   0   0  40  20  60
Apalachicola  83  70  83  76  81 /   0   0  30  60  80


FL...High Rip Current Risk until 6 PM CDT this evening for South



SHORT TERM...Fournier
LONG TERM...Fournier
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