265
FXUS64 KHUN 031430
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
930 AM CDT Fri May 3 2024

...New NEAR TERM...

.NEAR TERM...
(Rest of Today)
Issued at 930 AM CDT Fri May 3 2024

The forecast this morning has already proved to be tricky. QPF
amounts have already over preformed and CAMS have struggled to
accurately depict morning rain and storms. This is not necessarily
surprising as we have a summer like system moving through
consisting of weakly forced shortwaves that CAMS notoriously
struggle to grab on to.

Based on the over performance of morning rain, this gives
credence to higher QPF amounts likely seen through the weekend,
however that will be further addressed in the afternoon forecast
package. For the rest of today, current observations indicate an
area of convergence extending NW to SE through the CWA. Weak
showers will likely continue to develop along that axis over the
next few hours ahead of the arrival of the next short wave. This
afternoon into this evening, the next shortwave is forecast to
move through the area but there is significant disagreement in the
models as to the coverage of showers and storms associated with
it. Right now the most likely scenario seems that pop up summer
like convection will develop first from surface heating in the mid
afternoon resulting in isolated showers and thunderstorms across
the area. Later in the evening, higher coverage of showers and
storms is expected with the arrival of the shortwave. Two
scenarios seem possible with the second shortwave: 1.) most of the
area seeing light to medium rain through the evening, or 2.) a
band of showers setting up along one axis only impacting a limited
area. With such poor model guidance so far, the solution may not
be apparent until it begins to unfold.

Fortunately, there is no severe threat associated with these
shortwaves, frequent lightning and periods of heavy rainfall will
however still pose a threat to outdoor activities.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 433 AM CDT Fri May 3 2024

Fairly high POPs will remain warranted across the region
overnight, as broad scale vertical motions will increase slightly
with the passage of a weak mid-level shortwave trough to our
northwest. The risk for thunderstorms will remain highest this
evening (prior to the onset of the diurnal cooling cycle), with a
gradual transition to light rain expected by early Saturday
morning. Due to the abundance of moisture in the boundary layer
and only light southerly winds, patchy fog will be possible for
many locations as well.

Present indications are that the general synoptic pattern across
our region will change very little on either Saturday or Sunday,
although with indications of low-amplitude shortwave ridging
across the region on Saturday (in the wake of the shortwave
trough), coverage of afternoon showers and storms will likely be
somewhat lower compared to today. By late Sunday afternoon or
Sunday evening, the marine warm front (discussed in the near term
section) will begin to lift northeastward through the CWFA as a
strong upper low tracking into the central Rockies induces surface
pressure falls across the high Plains of eastern CO/WY. This will
likely support a fairly high coverage of showers and
thunderstorms Sunday evening. Highs will be in the u70s-l80s once
again tomorrow, before warming into the l-m 80s Sunday, and lows
should remain in the l-m 60s through Monday morning.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 433 AM CDT Fri May 3 2024

After warm frontal convection spreads northeastward and out of
the region late Monday morning, the TN Valley will be solidly
within a very warm/moist tropical airmass, with dewpoints expected
to rise into the m-u 60s as southwesterly low-level flow
strengthens. Although this will contribute to greater instability
(especially during the afternoon hours), a mid-level ridge will
shift across the region downstream from the central Rockies upper
low as it begins to spread northeastward into the northern Plains,
and this should yield a lower coverage of mainly afternoon
thunderstorms from Monday-Wednesday. Overnight lows will steadily
increase into the u60s-l70s through the middle of next week (due
to both elevated SW winds and moisture advection), with highs also
warming into the mid (to perhaps upper) 80s by Wednesday.

Although details are unclear at this time range, conditions will
become more favorable for convection at the end of the extended
period (Wednesday night/Thursday), perhaps in the form of MCS
activity that may initiate along a cold front to our northwest and
propagate southeastward into the local area. Should this scenario
materialize, conditions will be favorable for organized severe
thunderstorms across our region, with boundary layer dewpoints in
the u60s-l70s beneath a belt of mid-level WSW flow of 35-45 knots.

&&

.AVIATION...
(12Z TAFS)
Issued at 554 AM CDT Fri May 3 2024

Pockets of rain and embedded TSRA will continue to spread eastward
across the TN Valley this morning, warranting TEMPO groups at both
terminals thru 15Z. After a brief break in precipitation late this
morning, additional showers and thunderstorms will develop this
afternoon within the warm and increasingly humid airmass across
the local area. PROB30 groups have been included for this activity
btwn 20-02Z, as this is the timeframe when AWWs for lightning may
be required. Although the risk for convection will gradually
diminish this evening, light rain and fog may persist across
portions of the area thru the end of the TAF period. Prevailing
sfc winds will remain from the SSW at speeds of 5-10 knots.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

$$

NEAR TERM...RAD
SHORT TERM....70
LONG TERM....70
AVIATION...70