Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Huntsville Alabama
346 am CDT Tuesday Jun 2 2015
The cold front that generated convective activity yesterday has now
pushed to the southeast of the forecast area. Latest water vapor
imagery shows the upper level closed low circulating over the
Tennessee Valley and moving slowly to the E/se. Strong ridging was
beginning to build into the Southern Plains...as an upper level
trough moved ashore on the West Coast. The only evidence of the cold
front is the wind shift...with temperatures remaining in the middle to
upper 60s and dewpoints just a degree or two lower per the 07z
surface observation. Fog was beginning to develop across a good portion of
the area due to the high surface moisture and light winds...and there
could be a few spots with visibilities below 1 mile before the sun
The upper level low will continue to slowly move east during the
day...not making much progress. Forecast models are in fair
agreement that the axis of the low will reach into northwestern
Georgia and become nearly stationary during the short term.
Meanwhile...the ridge over the Southern Plains will build into the
western zones. Rain chances will remain low...with only a slight
chance of thunderstorms for the far eastern counties in the forecast
area...where the influence of the upper low and greater moisture
resides. This pattern will continue through the work week...with
below normal temperatures moderating to near normal by Friday.
As the upper ridge continues to build into to our west...the upper
low will finally become absorbed in a longwave trough...currently
over the northeast...and push east of the area. The eastern
periphery of the ridge will move across the forecast area...with
surface winds becoming southerly by the end of the weekend. This
will set the stage for an unsettled period across the region.
Southerly surface flow will increase the moisture
availability...while northwest flow aloft will allow upstream disturbances
to move into the region. While this is a pretty classic setup for an
mesoscale convective system or two to move across the forecast area...forecast models rarely
key in on the timing of these systems and will leave the chance probability of precipitation
in for the extended. Meanwhile...temperatures will remain around
normal values through the end of the period.
/issued 1215 am CDT Tuesday Jun 2 2015/
for 06z tafs...
moist and somewhat more stable conditions should continue through the
overnight...in the wake of a weak cold front passage on Monday. The
region will be on the edge between VFR and MVFR for much of the night.
Given MVFR ceilings have been present over kmsl...have kept MVFR over northwest
Alabama tonight. Lower altitude clouds should move across the central
region later tonight. Kept IFR ceiling and possible visible values before
daybreak Tuesday. Daytime heating and mixing should return VFR conditions
by the late morning...continuing into the remainder of the taf.
Isolated showers/storms are possible Tuesday afternoon...but chances are
too low to include in taf this issuance.
Preliminary point temps/pops...
Huntsville 80 61 84 64 / 10 10 20 10
Shoals 79 60 83 62 / 10 10 10 10
Vinemont 78 59 82 62 / 10 10 20 10
Fayetteville 76 58 80 60 / 10 10 20 20
Albertville 77 59 82 62 / 20 20 30 20
Fort Payne 78 59 80 61 / 20 20 30 20
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