Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 271723
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1223 PM CDT Sun Jul 27 2014

.UPDATE...
Issued at 1223 PM CDT SUN JUL 27 2014

Will the cap hold or won`t it? That is the question of the day.
We will continue to monitor for development through the afternoon,
mainly across west Kentucky.

The AVIATION section has been updated for the 18Z TAF issuance.

UPDATE Issued at 1021 AM CDT SUN JUL 27 2014

VAD wind profiles across the region this morning indicate that
25-30kts of westerly momentum is available to mix down today.
Portions of west Kentucky should reach Lake Wind Advisory criteria
this morning, and most locations along and east of the Mississippi
River should easily reach criteria behind the cold front this
afternoon. The strongest winds should be later this afternoon
behind the front. A Lake Wind Advisory has been issued for all but
the 6 westernmost counties of southeast Missouri until 7 PM.

The cu field has a very stable look to it over southern Illinois
and southwest Indiana, so it is safe to say the cap is still
overhead. The convection allowing models are having a hard time
developing much convection over our region through the day. Figure
the best chances will be right along the eastern border areas, and
possibly along the TN border late this afternoon, when the front
reaches that region. Kept PoPs in the 20-30% range and used areal
coverage wording. If storms can develop, supercells will be
possible with damaging winds and large hail the main concerns. The
storms will be moving quickly to the east southeast, so would not
expect much of a heavy rain threat. For spotters out there, keep
in mind that the storms will be oriented about 90 degrees from
what we typically see.

Temperatures are running hot over the southern half of the area
where there is plenty of sunshine as of 15Z. Sped up the warming
trend this morning, but figure increasing clouds and eventually
some cool advection will cut off warming early this afternoon.
High temperatures were not impacted signficantly. The dewpoint
forecast was on track and looked reasonable through the day, so
with a minor increase in temperature, heat indices are really
pushing Heat Advisory criteria this afternoon. Confidence in the
temperature and dewpoint trends is too low to issue at this time,
but will monitor for possible issuance around midday.

&&

.SHORT TERM...(Today through Tuesday night)
Issued at 302 AM CDT SUN JUL 27 2014

Biggest forecast challenge comes with a conditional probability of
some severe thunderstorms today...generally along and south of the
OH River. Potent cold front will be surging south into very moist
and unstable regime today. Sfc dew points are already pooling
into the mid 70s across this region...and temperatures by noon
will likely already have surged into the 90s. Cold front should
have progressed south to somewhere near the OH River by early PM.
Two factors that could limit/suppress convective development
include limited deep moisture and thermal capping that may be
present. If storms mange to form though...they will have more than
enough CAPE and bulk shear to work with to reach severe levels.

Cold front should be south of the region by early evening, ending
any storm threat and allowing much cooler and less humid air to
flow into the region overnight. The remainder of the short term
will be dominated by unseasonably cool and dry conditions, which
seem to be returning every week or so. Quite unusual for late July.
In fact, should be within a few degrees of record lows by Tue
morning.

.LONG TERM...(Wednesday through Saturday)
Issued at 302 AM CDT SUN JUL 27 2014

By Wednesday, weak sfc high pressure will be settled over the
region, as a large upper trough continues to impact the eastern half
of the nation with an upper level low pinwheeling over eastern
Canada. Even though models hint at minor disturbances in this
northwest flow pattern, moisture will be confined to just the lower
levels on Wednesday and early Thursday, so we should remain dry for
the most part. By Thursday night, a strong wave is progged to move
through the area which might be enough to produce some convection,
especially given the fact that moisture should be increasing aloft
by that time too. Will keep POPS low at this point.

The bigger synoptic change will come at the end of the week and into
the weekend, when an even stronger piece of energy digs down across
the western Great Lakes and carves a deeper trough over our region
and eventually a cut off upper low develops over/near the region
during the weekend sometime, though models are still not agreeing on
timing and location attm. This should bring an increasing chance for
precipitation. This general idea is also supported by the 12z/00Z
GFS precipitation ensembles, which hint at the possibility of
convection with this upper system. No real warm surges expected this
week as H85 temperatures really remain unchanged in the extended as
sfc winds/low level winds remain out of the north/northeast. These
N/NE winds will also keep dewpoints at bay, which means humidity
levels should remain fairly comfortable, especially for late
July/early August.

&&

.AVIATION...
Issued at 1223 PM CDT SUN JUL 27 2014

It appears at this time that any convection today is likely to be
south and east of the terminals. The thick cu deck should settle
in at VFR levels, and it should generally thin out through the
afternoon. The cold frontal wind shift will take winds to the west
northwest at KCGI and KEVV right at the beginning of the period,
and KPAH and KOWB through the afternoon. As winds become northwest
mixing may take gusts up above 20kts at times. The main issue for
tomorrow will be an expansive stratocu deck as the cooler air
aloft advects over the region. Cannot rule out some MVFR ceilings
at KEVV and KOWB in the late morning.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...LAKE WIND ADVISORY until 7 PM CDT this evening FOR ILZ075>078-
     080>094.

MO...LAKE WIND ADVISORY until 7 PM CDT this evening FOR MOZ076-087-
     111-112-114.

IN...LAKE WIND ADVISORY until 7 PM CDT this evening FOR INZ081-082-
     085>088.

KY...LAKE WIND ADVISORY until 7 PM CDT this evening FOR KYZ001>022.

&&

$$

UPDATE...DRS
SHORT TERM...GM
LONG TERM...CW
AVIATION...DRS





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