Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 271521
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1021 AM CDT Sun Jul 27 2014

.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 1135 PM CDT SAT JUL 26 2014

A cold frontal boundary is forecast to cross all TAF sites on
Sunday but with a small capping inversion and lack of deep
moisture, it will likely be a dry frontal passage, so did not
mention anything at this time. South southwest winds AOB 10 knots
overnight will pick up out of the west at 12-14 knots gusting to
20-22 knots after 15Z, then veer around to the northwest AOB 10
knots around in the wake of the FROPA.


&&

.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...JP






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