Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Huntsville Alabama
239 PM CDT Monday Jul 6 2015
water vapor this afternoon continues to show an upper wave slowly
making its way through southeast Missouri with a fairly dry
atmosphere ahead of it. Showers and thunderstorms have had a very
hard time developing this afternoon...which may be caused by a weak
capping inversion indicated on laps/NAM soundings.
There are some indications the previously mentioned wave will make
it across the local area tonight and help develop a few showers
through the evening and overnight. There is quite a bit of dry air
building in though which will limit widespread shower development.
It does seem the NAM is overdoing the cape so will lean towards a
more stable environment indicated by the GFS. Not confident enough
to go completely dry for the night so will continue the mention of
isolated showers/thunderstorms due to that wave approaching.
A subtropical ridge from the Atlantic will start to back build over
the southeastern U.S. As a cold front drapes itself from SW Texas
through the Great Lakes. We will avoid much of the rainfall with this
front as it stalls but with the possibility of outflow boundaries and
pre frontal troughs extending from it...will continue the 20 probability of precipitation for
Tuesday through Wednesday night. In general...most of the area will
remain dry through this time frame. At the same time...heights will
rise...and temperatures will be on the increase. Southerly flow will also
help keep the dew points in the upper 60s to near 70 Tuesday-Thursday bringing
heat index values to near 100 by the end of the week. Met/NAM
guidance seems to be running warmer than the mav/GFS by a few degrees
this week...so will be going with a blend but leaning towards the
warmer values as we should have a decent amount of sun each day.
The upper ridge continues to build west and encompasses much of the
southern US by the weekend. Even with it building...heights/850
temperatures do not increase much allowing highs to only rise into the
lower 90s for the weekend and the beginning of next week. The GFS is
much more aggressive with afternoon precipitation through the time frame
with the European model (ecmwf) much drier. There really is not much support at the
surface or aloft for showers/thunderstorms but with the hot and
humid conditions and northwest flow through the column...going to continue
slight chance probability of precipitation each afternoon. But once again...much of the area
should be dry.
/issued 1257 PM CDT Monday Jul 6 2015/
for 18z tafs...
VFR conditions have returned to kmsl/khsv sites...and should
continue into the evening. Isolated convection is possible this
afternoon... mainly in the vicinity of kmsl. Otherwise...VFR weather
is expected for the area. SW winds around 10kt this afternoon should
become light from the south-southwest after dusk. SW winds around 10kt are expect
a few hours after sunrise Tuesday. Residual moisture may result in brief
MVFR fog/mist forming around daybreak Tuesday...but confidence is too low
to include in this issuance.
Preliminary point temps/pops...
Huntsville 69 91 72 91 / 20 20 20 20
Shoals 69 91 73 92 / 20 20 20 20
Vinemont 69 90 72 90 / 20 20 20 20
Fayetteville 67 88 70 89 / 20 20 20 20
Albertville 67 90 70 90 / 20 20 20 20
Fort Payne 65 88 70 90 / 20 20 20 20
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