Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 202027

327 PM CDT Sat Sep 20 2014

.SHORT TERM...(This afternoon through Monday night)
Issued at 327 PM CDT SAT SEP 20 2014

Weak surface theta-e convergence, insolation under weakening low
level ridging will continue to support isolated to widely
scattered convection through the late afternoon hours.

The differential heating should diminish as insolation and cirrus
canopy reduce gradients of instability for the remainder of the
afternoon. A vast majority of the instability should shift to the
Southern Pennyrile for the remainder of the afternoon, so rain
chances will likely increase during the middle and late afternoon hours.

A disjointed zone of differential vorticity will support marginal
lift across the approaching baroclinic zone with the surface
representation indicated with the surface cold front. As the upper
level trough supporting the cold front moves southeast, the trend
will be for the trough to shear out with time, reducing the
potential for focused convection. For now, the PoPs and Weather
have been left in chance category or less.

Stability will build in fairly rapidly during the morning hours,
quickly diminishing any remaining shower activity through Sunday.

Northwest flow and ridging will then dominate, bringing back
seasonable temperatures and dry weather for the official beginning
of the Fall season.

.LONG TERM...(Tuesday through Saturday)
Issued at 327 PM CDT SAT SEP 20 2014

A series of shortwave impulses along the U.S. West Coast will
continue keep a net trough pattern along the Western U.S. at the
beginning of the extended forecast period (Tuesday). Persistent
downstream ridging and a weak moisture convergence will limit
focused potential for convective activity through the remainder of
the week. With the West Coast blocking pattern in place, rain
chances will be nil through the upcoming weekend.


Issued at 1241 PM CDT SAT SEP 20 2014

Cu (Cumulus) field well represented under ridge across the WFO PAH
TAF sites near the beginning of the 18z Saturday forecast. With
local convergence and insolation fixed along a KFAM-KCUL line as of
17z, isolated convection may impact the terminal sites this
afternoon. However, given the limited coverage expected at this
time, decided to keep the mention of rain out of the area through

Likewise, added a mention of vicinity showers to the forecast for
the peak period of precipitation potential through 18z Sunday. At
this point, am not confident to input more than VFR ceilings in
the proximity of the TAF sites.




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