Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 211725

1225 PM CDT Mon Jul 21 2014

.SHORT TERM...(Today through Wednesday)
Issued at 240 AM CDT MON JUL 21 2014

Dry conditions will continue through early week as an upper level
ridge centered over the Central and Southern Rockies builds east
into the Mid Mississippi Valley. The weak upper level low/trough
that has lingered over eastern portions of the area will be
shunted into the southern U.S. during this time. As a result,
expect more sunshine and less cloud cover through Tuesday. Warmer
temperatures will also result. Expect upper 80s today, then lower
90s Tuesday and Wednesday. Afternoon heat index readings tomorrow
and Wednesday will reach into the mid and possibly upper 90s.

A southward push in the jet stream will once again bring a cold
front into the region on Wednesday. The front will bring our next
chance of showers and thunderstorms. Exactly how Wednesday plays
out is uncertain at this point. Most models hint at a possible
influence from remnant overnight activity across northern portions
of the area during the morning. Then by afternoon, I am not
entirely confident the mid level cap will be eroded as models
currently suggest. As a result, we will keep probabilities in the
chance category on Wednesday for now.

.LONG TERM...(Wednesday night through Sunday)
Issued at 240 AM CDT MON JUL 21 2014

The upper level ridge responsible for dry, hot, and humid conditions
in the short term portion of the forecast will have begun to
retrograde back to the west at the beginning of the long term
period. As a result, this puts our region back in northwest flow
aloft which typically delivers cooler and less humid conditions with
an occasional frontal passage, which is not a common occurrence in
the latter half of July in the mid latitudes, but certainly a
welcomed one.

Anyway, the long term period begins with the passage of the first of
multiple frontal boundaries that will impact the region`s weather
during the period. With the passage of the first boundary, with
decent upper support and moisture, precipitation chances will be
very good Wednesday night, especially over the southeast half of our
CWA. Precipitation chances will taper off from the northwest on
Thursday in the wake of the front.

At this time Thursday night and Friday appear to be dry as surface
high pressure overspreads the area. Precipitation chances make their
way back into the forecast starting Friday night as the
aforementioned frontal boundary lifts back northward as a warm front
across our area in response to a developing weather system over the
central plains. The presence of the boundary and a series of ripples
of energy in the upper flow will provide the focus for shower and
thunderstorm development.

Precipitation chances remain in the forecast through the end of the
period as the frontal boundary associated with the developing system
along with upper support and decent moisture approaches and
ultimately crosses our area on Sunday. Even with two cold frontal
passages in the long term, the latest SPC day 4-8 outlook shows no
threat for severe storms at this time.

Beyond Thursday temperatures and dewpoints moderate back to near
normal levels by the end of the period.


Issued at 1225 PM CDT MON JUL 21 2014

The moisture and wind gradient associated with the narrow ridge
axis oriented northeast to southwest across the area is allowing
the intrusion and development of diurnally-based 3-5kft
few/scattered/locally broken cloud bases/ceilings along the Ohio
and Wabash River valleys and Southeast Missouri.

Kept a mention of VFR/upper MVFR visibilities after midnight at
each TAF site. Introduced MIFG to account for denser patches of
LIFR visibilities due to microclimate influences.

Otherwise, VFR conditions will continue to dominate through the
forecast issuance period.




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