Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 082354

Area Forecast Discussion
National Weather Service Huntsville AL
554 PM CST Thu Dec 8 2016

For 00Z TAFS.


.NEAR TERM...(Tonight)
Issued at 251 PM CST Thu Dec 8 2016

Latest visible satellite imagery indicates that clouds are finally
starting to erode across the TN Valley, as high pressure slowly
builds across the region. Although, some locations are still mostly
cloudy, the overall trend and short term guidance suggests that skies
will become mostly clear after sunset. Meanwhile, northwest winds
were continuing to advect much colder and drier air into the forecast
areas. Latest obs show most of the area in the upper 30s to lower
40s, which is not much higher than observed lows. Winds will slack
off a bit after nightfall, however will still maintain 5 to 10 kts
overnight. With the mostly clear skies expected, temperatures will
fall into the teens to lower 20s. This will combine with our light
winds to create very cold wind chill values, with locations in the
higher elevations experience single digits. This is also expected to
be a long duration freeze event, as our temperatures will fall below
freezing between 9 and 10 pm and will likely remain below freezing
through much of Friday morning.

.SHORT TERM...(Friday through Saturday night)
Issued at 251 PM CST Thu Dec 8 2016

The center of the surface high will continue to shift to the east-
southeast on Friday, with mid and upper level riding builds into the
area. Strong northerly flow will continue to advect colder air
southward, and daytime highs will remain in the low to mid 30s,
despite clear skies. As the surface highs becomes centered over the
TN Valley Friday night, winds will calm and very good radiational
cooling conditions will be present. Thus, temperatures are expected
to fall into the upper teens across most of the area, the exception
being near our larger bodies of water. The axis of the ridge will
move to our east on Saturday, with southerly flow returning to the
area. Temperatures will warm into the lower 40s by Saturday
afternoon, under mostly clear skies and fall to more seasonal values
of around 30 degrees Saturday night.

.LONG TERM...(Sunday through Wednesday)
Issued at 251 PM CST Thu Dec 8 2016

The majority of Sunday will remain dry as sfc high pressure
wedges into the eastern part of the state. As it moves off to the
northeast throughout the day, southerly winds will pick up and a
slight chance of showers are possible in NW AL in the afternoon. An
inverted trough will lift from the southern Plains up into the Great
Lakes by Sunday night, with a cold front not too far behind. Look
for showers to start Sunday night and spread from west to east as
the cold front approaches early Monday afternoon. When I say cold
front, I do  not mean a major temperature change like the front we
just experienced...Monday`s low will be in the 40s. The placement of
the sfc high that builds in behind the cold front Monday night will
determine the coverage of lingering POPs and could affect temps as

Another system will approach the region on Tuesday with a stronger cold
front moving into the area around Wednesday morning. On Tuesday,
highs will be in the mid 50s with a chance of rain. Colder air
will arrive with the front and as temps drop, precip will linger, so
there could be a chance of snow mixing in with the rain in the far
northern portions of the CWA after midnight. Temps came in quite
warmer with this forecast package but pulled back across the board by
a few degrees. Not as confident about this RA/SN mix at this time but
will keep an eye on the trend as we continue to get closer.

Beyond any lingering precip on Wednesday morning, it will be cold
with highs in the low/mid 40s with decreasing clouds.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 554 PM CST Thu Dec 8 2016

A plume of subtropical moisture embedded within fast wswly flow aloft
will continue to provide high-level ceilings aoa 12 kft at both
HSV/MSL this evening. This layer of cloudiness is expected to shift
steadily sewd and should clear both terminals btwn 09/04-06Z, with
SKC anticipated until a few high clouds arrive once again late in the
period. Nw sfc winds in the 8-10 knot range will gradually veer to
nnw and diminish thru the TAF period, as center of arctic high
pressure builds sewd into the mid-MS valley region.





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