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Area forecast discussion 
National Weather Service Huntsville Alabama
1202 am CST Tuesday Feb 9 2016

Update...
for 06z tafs

&&

Discussion...
/issued 958 PM CST Monday Feb 8 2016/
the current short term forecast grids are in good condition with no
significant changes planned at this time. Current water vapor
satellite data continues to indicate an amplified middle/upper-level
longwave trough encompassing much of the eastern Continental U.S. This
evening...with a distinct vorticity maximum embedded within this trough
digging east-southeastward into Kentucky. This feature is responsible
for sending a secondary/reinforcing surge of cold air into the Tennessee
Valley...noted by a recent increase in west-northwest flow at several
observation sites around the region. Low-level convergence along the
advancing wind surge has resulted in an increase in snow flurries and
light snow showers -- which will continue to impact NE Alabama and
southern Tennessee through 11 PM.

For the remainder of the night...strongest middle-level forcing for
ascent associated with vorticity maximum spreading east-southeastward across
Kentucky and into the central Appalachians will be focused to the
North/East of the region...where probs for measurable snow will be
greatest. However...a glancing influence from this vorticity maximum may
impact our southern Tennessee counties -- where locations in elevated terrain may
see snowfall accumulations up to one-half of an inch by sunrise.
Forecasted low temperatures may be a degree or two too cold based on
expectations of thick cloud cover and elevated winds overnight...but
wind chills will still manage to fall into the 15-20 range by 12z.

Recent model data continues to suggest that conditions will become
more favorable for snow -- perhaps as early as sunrise -- as the
nose of 130-140 knots upper speed maximum currently digging southward over
the Central Plains begins to impinge on the region. Increasingly
diffluent flow aloft beneath the left exit region of this speed maximum
coupled with weak lower-level isentropic ascent should provide
sufficient lift within a favorable thermodynamic environment for
fairly widespread snow tomorrow morning/afternoon -- especially for
the NE half of the County Warning Area where ascent will be maximized.

70/dd

&&

Aviation...
for 06z tafs...upper-level trough remains anchored across the region
this evening...with VFR ceilings currently in the 5-10 kft range based
on latest observation from hsv/msl. Stratus deck will begin to lower within
first hour or so of valid taf...as a disturbance within the trough
approaches the region from the west. MVFR ceilings should develop from
west-to-E between 09/08-10z with threat for -shsn increasing as well. Light
snow or snow showers will likely become widespread beginning around
15z...and continuing until roughly 00z with ceilings expected to remain
in the 2500-3500 feet range through end of taf period. West-northwest surface winds will
diminish to around 8 kts during the hours around sunrise...before
increasing to 12g20 kts once again by 15z. Flow will veer and
diminish after sunset tomorrow.

70/dd

&&

Hun watches/warnings/advisories...

Alabama...Winter Weather Advisory from 6 am to 6 PM CST Tuesday for alz009-
010.

Tennessee...Winter Weather Advisory from 6 am to 6 PM CST Tuesday for tnz076-
096-097.

&&

$$

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at weather.Gov/Huntsville.

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