271
FXUS64 KJAN 202342 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
642 PM CDT Mon May 20 2024

...New AVIATION...

.DISCUSSION...
Issued at 217 PM CDT Mon May 20 2024

Through midweek (Tonight-Wednesday night)...

Tonight-Tuesday: As the mid-level ridge axis builds northeast from
the Bay of Campeche & Mexico, the low-level ridging & thermal
capping will increase across the Gulf Coast states. Sfc & thermal
ridge will be centered over the Carolinas to Atlantic seaboard,
while return southerly flow will pick up across the Gulf Coast to
Mid South region. Longwave pattern will consist of deepening
shortwave/strong sfc low pressure system moving into the Mid West.
Building 593-595DM ridge over Bay of Campeche & Mexico will deflect
any concerns well off to the northwest through Tuesday. Thermal
capping is expected with 10-12 deg C range 700mb temps & PWs only
in the 1-1.25 inch range, with dry 850-700mb RH`s in the 30-40%
range. This will suppress any convection chances & lead to a dry &
warm pattern. For tonight, expect a dry night but WAA & some
crossover temps in the Pine Belt from advection of upstream Gulf
moisture could lead to some patchy to even patchy dense fog. Added
an "Limited" for isolated cases of patchy dense fog. HREF probs
support even increased messaging & more expansive areal
configuration in HWO graphics. Going with most confident area in
an area along & southeast of a line from Brookhaven to Mendenhall
to Bay Spring. Thermo pattern in the mid-upper teens to low 20s
degree C at 850-925mb layers support continued seasonable warmth
in the upper 80s to low 90s Tuesday aftn & possible a site could
again peak in mid 90s. Heat stress won`t be a concern but
increased humidity will aid in heat indices climbing into low-mid
90s. Seasonably warm lows are expected tonight & Tuesday night, in
the mid 60s southeast of the Natchez Trace to upper 60s-low 70s.
Patchy fog to even patchy dense fog can`t be ruled out again
Tuesday night but keeping out of the HWO graphics for now.

Wednesday: As the strong trough/low pressure system eject into Great
Lakes-southern Canada, height falls are expected on the northern
extent of the subtropical ridge across the Mid South to Gulf Coast
States. This will be along a frontal system sagging across these
zones & extending northeast into the OH Valley to Mid Atlantic
states. Southerly return flow of warmth & moisture will persist,
with thermal profiles still supportive of some capping while some
relaxation in the Hwy 82 corridor & northwest of the Natchez Trace.
Seasonably warm highs into the upper 80s to low 90s & lows in the
mid-upper 60s to low 70s Wednesday night again are expected.
Increased moist ascent support isolated rain & storm chances into
the extreme northwest ArkLaMiss Delta. In these areas, if some
storms could sneak in, there is enough deep shear >40kts & lapse
rates/vertical totals in the 25-27 deg C range for a low end
threat of isolated strong-severe storms, so leaving HWO graphic as
is. /DC/

Thursday into early next week...

As we go into late week, the ridge will get flattened and we will
see a more quasi-zonal regime get established followed by a
potential NW flow pattern for Sun-Tue as a more substantial large
scale trough sets up across the E CONUS which looks to eventually
push a cool front and dry air into the area by middle of next
week.

The sensible weather from this evolving pattern supports warmth and
increasing humidity. Low level temp anomalies are on the (+) side
and we will reside in the 90th to 97th percentile of 850mb temps. We
should see quite a bit of 90-95 degrees for MaxT. MinT will be above
normal as well and mostly in the upper 60s to lower 70s before we
see more lower 70s by the weekend and ahead of any boundary next
week. Other concerns will be for an active storm period potentially.
By no means is this locked in, but such an active zonal flow pattern
with multiple decent waves moving through from Thu into early next
week should support at least one day of decent storms if not a
couple. Northern areas seem more prone from Thu-Sun as this area is
closest to the source region and any MCSs coming from the S Plains.
These are always low predictability situations and will need to get
closer to those days to get a better handle on things. Early week,
ahead of the main cool front, would offer at least one opportunity
for most of the area to see some stronger activity. This is still in
the 6-8 day realm, so we have plenty time to watch. /CME/

&&

.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Mon May 20 2024

VFR conditions will prevail through the TAF period. /22/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       67  90  68  88 /   0   0   0   0
Meridian      66  89  67  90 /   0   0   0   0
Vicksburg     68  90  70  89 /   0   0   0   0
Hattiesburg   67  90  67  90 /   0   0   0   0
Natchez       67  89  69  88 /   0   0   0   0
Greenville    71  92  73  89 /   0   0   0  10
Greenwood     69  91  71  90 /   0   0   0  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

DC/CME/22