Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 250818

Area Forecast Discussion
National Weather Service Huntsville AL
318 AM CDT Tue Jul 25 2017

.NEAR TERM...(Now through Today)
Issued at 330 AM CDT Tue Jul 25 2017

Satellite imagery this early morning is showing a thin cloud deck
with some enhanced moisture coverage across north central AL. While
dew point depressions are generally around 1-2 degrees, with calm
winds, fog formation is slow to develop given lingering clouds. Have
retained patchy fog wording for the 9Z-12Z timeframe across the CWA
as development in some prone areas could form quickly as we approach

For the rest of today, very weak surface ridging remains over much of
the SE today. The ridge axis itself remains well south of the area
which will help to maintain light (variable at times) W to NW winds.
Plenty of moisture and ample instability are available for isolated
to scattered thunderstorms again today, however, we`ll see a
strengthening of the mid level ridge from the west. Therefore, best
chance of rain today will be the eastern zones.

.SHORT TERM...(Tonight through Thursday)
Issued at 330 AM CDT Tue Jul 25 2017

Not much change in the over pattern through Thursday. Surface ridge
axis remains south of the area while the mid to upper level ridge
become more defined over the SE. If anything, stronger ridging
through mid week will keep thunderstorm chances rather limited but
reintroduce the heat, given the lack of cloud cover. Current trends
in the temp forecast shows highs back in the low to mid 90s by
Wednesday and again on Thursday. Dew points remaining in the low to
mid 70s will give us heat indices in the low 100s, especially for
areas west of I-65.

.LONG TERM...(Thursday night through Monday)
Issued at 330 AM CDT Tue Jul 25 2017

The forecast for the weekend and into early next week hasn`t changed
much since this time yesterday. A fairly strong ridge of high
pressure will be anchored to the W of the TN Valley by this time in
the forecast period, with the CWFA in NW flow thanks to a trof in
place over much of the E coast. As a disturbance rounds the base of
the departing trof to our E, this will drag a cold front toward the
area for the Friday/Saturday timeframe. Though the front looks to
actually push *through* the area (which doesn`t happen too often
this time of year), any respite from the humidity will be short
lived as it begins to meander back northward by Sunday/Monday. At
the same time, the Bermuda high will retrograde Wwrd, which will
pinwheel moisture Nwrd across the TN Valley. This will set the stage
for at least isolated to scattered showers and storms as we head
into the new work week ahead, with daily diurnal convection lingering
through the end of the period.

Temperatures during this portion of the forecast will generally be a
bit lower than they have been recently. Instead of mid/upper 90s
each day, the more scattered the convection, the greater the cloud
cover, and therefore, the lower the aftn high temperatures in the
afternoon. As such, we`re looking at topping out in the middle to
upper 80s each day. Aside from the weekend morning lows starting a
little `cooler` (in the middle 60s), morning lows otherwise will
start out in the lower 70s with patchy fog here/there depending on
the coverage of convection from the previous day.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1237 AM CDT Tue Jul 25 2017

VFR conditions are prevailing at the moment. However, we will be
monitoring the fog potential overnight as dew point depressions are
around 1 degree area wide. With the moist conditions in place and
winds becoming calm, have decided to reduce vsby around 9Z to 2SM
and will tempo for IFR or LIFR conditions if necessary. Any fog
development should lift an hour or two after sunrise with generally
VFR conditions prevailing through the afternoon. Scattered
thunderstorms possible again later this afternoon, but not confident
to put TS in current forecast.




NEAR TERM...Barron

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