Area Forecast Discussion
Issued by NWS Paducah, KY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

000
FXUS63 KPAH 181643
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1143 AM CDT Thu May 18 2017

.UPDATE...
Issued at 1143 AM CDT Thu May 18 2017

Many locations are have been at or above Lake Wind Advisory
criteria already this morning, but all guidance indicates that the
winds will be weakening through the afternoon. Will not be issuing
an Advisory at this time.

As for convection, latest HRRR output develops convection, mainly
over southeast Missouri in the next hour or so, and latest radar
trends support it. This appears to be where plume of low-level
moisture overlaps with cooling mid-level temperatures. Could see a
few strong updrafts initially, but wind fields are weakening and
the shear should be insufficient to support much of a severe
weather threat. However, relatively slow motion and PWs over 1.6"
do support a heavy rain and localized flood concern. It looks
like this activity will spread east of the MS River through the
afternoon, but most of the activity will dissipate by early this
evening.

UPDATE Issued at 712 AM CDT Thu May 18 2017

For aviation section only.

&&

.SHORT TERM...(Today through Saturday night)
Issued at 250 AM CDT Thu May 18 2017

Much of the short term will be spent in a warm sector type regime,
with daily scattered shower/thunderstorm chances and above normal
temperatures. We will remain sandwiched between a blocking H50
high pressure system over the southeast U.S. and low pressure out
over the Plains. Minor perturbations ejecting out the base of this
low will be difficult to time, but it seems as though the highest
storm chances may be diurnally enhanced as instability levels
should be greatest during the heat of the day. Most storms are
expected to stay below severe levels, though an isolated severe
storm here and there cannot be completely ruled out.

Showers/thunderstorms will become more numerous Saturday and
Saturday night as a cold front finally approaches from the west,
providing a more focused low level trigger. However, the low
level convergence along the front looks rather meek at this time.
The main mid/upper level short wave will also be pressing east at
that time which will lead to more widespread forcing aloft.
Cannot rule a out a few strong to severe storms as the front gets
closer, but timing of the front may come later at night into early
Sunday, which would limit the amount of overall instability to
work with.

.LONG TERM...(Sunday through Wednesday)
Issued at 250 AM CDT Thu May 18 2017

Again high confidence in the unsettled weather pattern for the
extended. The exact timing is coming into better agreement but have
doubts on the longevity of the rainfall which are in somewhat
contrast to forecast sounding.

Models have come into good agreement on fropa Sunday with the cold
front bisecting the FA around mid day Sunday. Instability index
values do exist for both elevated and surface based convection with
LI`s negative 1 to 3 and CAPE between 300 at the surface with MU
CAPEs approaching 1000 j/kg. K index values exceed 30c and
Showalters slightly negative. So organized storm will be possible
but widespread severe outbreak is not really expected at this time.
However any outflow boundaries from previous storms could interact
with the synoptic scale front or individual storms...so it will heed
close monitoring. In its wake cooler drier air rushes into the
region. This should rapidly cut off thunder at least in the
afternoon during peak heating. By Tuesday a reinforcing cold front
will come into the region on the heels of the weekend fropa. Again
there will be sufficient instability ahead of the front Tuesday for
convection albeit limited. Much drier and cooler will once again
follow which should limit or reduce the longevity of pops going into
Wednesday. Near normal temperatures Sunday will fall well below
normal for the first half of next week.

&&

.AVIATION...
Issued at 712 AM CDT Thu May 18 2017

Warm front should stay north of the region through the period.
Expect VFR cigs AOA 4000 ft. Could be brieflyl lower in scattered
shower/isolated thunderstorms, but should not be widespread enough
to mention explicily in TAFs. Southerly winds 10-20 kts will
subside at sunset.


&&

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

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.