Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Huntsville Alabama
255 am CDT Monday Apr 27 2015
a cool week is in store for the Tennessee Valley with both high and
low temperatures of 5 to 10 degrees below normal.
Closed upper level low located near the nm/Texas border and SW flow in
the upper levels will allow for cirrus clouds to stream into the area
and keep conditions partly cloudy today. As the closed low shifts
east through OK/Texas today...a surface low is forecast to develop along
the Texas Gulf Coast. This will bring US our next round of rain. Models
have showers beginning to spread into the region from west to east
Tuesday morning. Believe this is a bit quick...due to our surface
winds remaining out of the NE/east which should keep drier air near the
surface and prevent rain from reaching the surface. We dont begin to
saturate the lower levels until later on Tuesday and showers should
start in the afternoon. Showers should continue through morning and
then begin to taper off in the afternoon from west to east.
While we remain in the cool sector of the system and almost no
instability is noted in the forecast soundings. Could see a scenario
where...as the upper level low tracks over the area Tuesday
night/Wednesday morning lapse rates steepen and the forcing from the
low could allow for a few isolated thunderstorms to develop.
However...due to the low confidence in this have decided to keep the
mention of thunder out of the official forecast for Tuesday through
The forecast towards the latter half of the week is a little muddled.
There is some discrepancy in the handling of the upper level wave
transitioning across the northern plains and into the upper Great
Lakes region. Latest models take this wave from the Great Lakes
region and drop it south/southeast through the Midwest and into the
southeast US. This will merge/wrap up with the system exiting our area to
the east. There should be enough lift associated with this system
dropping down into the region to generate some light shower activity.
However...the overall extent of the shower activity will depend on
just how far west the low tracks as it drops south. There is enough
support from all the models and the GFS ensemble members to add a
slight chance for light showers Thursday afternoon/evening. The low
quickly shifts east on Friday and all activity should end Thursday
High pressure builds in behind this system and we should see a return
to normal temperatures by Sunday. Looking ahead to early next week we
will be under a mostly zonal flow and should see normal to slightly
above normal temperatures.
/issued 1247 am CDT Monday Apr 27 2015/
for 06z tafs...low clouds have now dissipated across the region.
However...high-level convective debris clouds will result in
persistent VFR ceilings between 15-25 kft through the valid taf period. Surface
winds will remain from the north-northeast-NE at 5-10 kts. Combination of high
clouds and elevated winds will reduce threat for br/fog compared to
points to the north.
Preliminary point temps/pops...
Huntsville 70 49 68 52 / 0 10 60 70
Shoals 70 49 67 50 / 0 10 70 60
Vinemont 68 49 66 51 / 0 10 70 70
Fayetteville 66 45 67 49 / 0 10 50 60
Albertville 68 48 67 52 / 0 10 70 70
Fort Payne 68 45 68 49 / 0 10 60 70
For more information please visit our website