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000
FXUS63 KPAH 101930
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
230 PM CDT Mon Mar 10 2014

.SHORT TERM...(This Evening through Wednesday Night)
ISSUED AT 228 PM CDT MON MAR 10 2014i

The trend advertised by the Canadian (GEM), GFS, and SREF guidance
for two distinct weather systems in the Middle and Lower
Mississippi Valley appears to be the preferred solution in the
transition from medium to short range forecast periods. The main
impact will be a slightly slower increase in PoPs and weather
coverage in the early evening Tuesday night and a faster
departure of the precipitation shield on Wednesday.

In the very short term period a three to five degree downward
adjustment had to be made for this afternoon over the Missouri
delta region into the Missouri Bootheel to account for residual
impact due to the extensive ice/sleet cover and antecedent, but
noticeable, surface moisture fields. Anticipated and adjusted
forecast for this afternoon, but transitioned toward a null difference
for the later part of tonight into Tuesday.

The NAM-WRF, RAP, and GFS LAMP guidance were the preferred short
range guidance for this package, initializing well and reflecting
a consistent trend from previous model runs.

The mention of thunderstorms was continued from yesterday`s
forecast package, mainly over Southeast Missouri and Southern
Illinois for early Tuesday evening. The NAM-WRF, and to some
degree the SREF guidance, hint that SFC/Boundary Layer/Mixed Layer
CAPE`s of 400-600 Joules per kilogram will be expended in the
23z-04z time frame in the aforementioned area. There may be just
enough shear for brief storm organization and that is reflected in
the 02z (900 pm CDT) grid where coverage of thunderstorms was
increased slightly. Low level lapse rates and shear (i.e., below
3km AGL) are marginal, but there is some 20-40 knot shear in the
3-6km AGL layer per the 12z Monday 12km NAM-WRF. Definitely can
understand by SPC considered a "See Text" for the aforementioned
area. Beyond 03z-04z Wednesday, low level stability, shear, CAPE
fields diminish sufficiently to drop further mention of
thunderstorms overnight into Wednesday morning. Essentially any
surface-based wind gust potential will likely be associated with
the passage of a surface low along the cold front. An annotation
will be made in the HWO (Hazardous Weather Outlook) to account for
the potential for gusty and/or damaging winds early Tuesday
Evening. Placed gusty winds in the grids for the early evening as
well on Tuesday.

The NAM-WRF suggest some isolated convective activity may pop up
as early as 4 pm CDT Tuesday over Southwest Illinois, but in the
absence of consistency, decided to eliminate any measurable
PoP/Weather for late Tuesday afternoon.

Still not sold on any mixed precipitation before most of the
precipitation moves out of the area. However, kept a mention of a
rain/snow mix in the 10z-13z (5 am - 8 am CDT) time frame along
and west of a line from Van Buren and Perryville Missouri onward
to Fairfield Illinois. Do not expect any accumulation at all in
this region.

Temperatures in the lower 70`s look reasonable for Tuesday, with a
drop back to the 40s to near 50 degree mark on Wednesday.


.LONG TERM...(Thursday through Sunday)
ISSUED AT 228 PM CDT MON MAR 10 2014

After the mid week system passage and cool down, the long term
portion of the forecast begins Thursday with a west-to-east
moderation, as the cooler trof departs eastward and heights rise
from the west. By Friday, a surface High has shifted east of the Tn
valley, and lower trop s-swlys have warmed the profile back toward
the 60s.

Friday night, the gfs hints at a little frontogenesis as some energy
wheels thru the broader cyclone to the north and east, but the ECMWF
suggests clouds only and both are weak in the surface reflections
and maintain relative high heights, so we`ll refrain on taking a
bite and mentioning pops (for now). The broad zonal westerlies thus
continue into the first half of the weekend, as should the milder
weather.

The models hint at change toward the end of the long term forecast
period, late day 6-day 7-beyond. The ECMWF is more vigorous than the
GFS, as both suggest strong height falls in the mid-upper Ohio
valley. This could lead to an early or mid week next cool down, and
possibly, some wintry pcpn. It`s too early to tell for now, but
we`ve introduced the beginning small pops for the system, and will
track/monitor its evolution closely in the coming days.

&&

.AVIATION...
ISSUED AT 228 PM CDT MON MAR 10 2014

S-SWlys will subside after sunset, and the terminal forecast will be
marked by a moclear early half sky, with increasing mid and high
warm cloud advection in the latter half of the valid forecast range.




&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$

SHORT TERM...Smith
LONG TERM...DH
AVIATION...DH