Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 292332
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
630 PM CDT Fri Aug 29 2014
Updated aviation section for 00z taf issuance
.SHORT TERM...(Tonight through Sunday night)
Issued at 316 PM CDT FRI AUG 29 2014
Shower and thunderstorm coverage should increase from the west late
this afternoon and evening with the approach of an upper level
trough from the plains. Until then, isolated to widely scattered
convection could pop up just about anywhere across our CWA.
Precipitation chances continue to increase area wide through
Saturday night with the upper trough axis remaining to our west
combined with deepening moisture streaming across the region.
Although widespread severe weather is not expected at this time,
precipitable water values will be in excess of 2 inches both
Saturday and Saturday night, so at this time it appears that locally
heavy rainfall will be the primary threat.
Latest model runs are in decent agreement in showing the upper
trough flattening/shearing out and whats left of it moving off to
the east on Sunday, therefore decreased precipitation chances from
the west on Sunday. Sunday night there may be small precipitation
chances from the aforementioned system lingering over our far
southeast counties as well as small precipitation chances over the
western and northwestern sections along the leading edge of a
system moving out of the plains.
Although there will be little change to dewpoints in the short term,
temperatures will return to near normal readings for both Saturday
and Sunday. This scenario will keep relative humidities elevated,
but afternoon heat indices should make outdoor work and other
activities much easier to handle.
.LONG TERM...(Monday through Friday)
Issued at 316 PM CDT FRI AUG 29 2014
From Monday through Wednesday morning, the WFO PAH forecast area
will be oriented along the southern border of faster westerlies at
the middle and upper levels of the atmosphere. This will impress a
sharp north to south baroclinic zone across the WFO PAH forecast
area, leaving the best chances for rain across the northern 1/3 to
1/2 of the area,
From Wednesday afternoon through Friday, a broad west to east high
pressure ridge will build northward, yielding warmer temperatures
aloft and capping the potential for showers and thunderstorms across
the area. There is a slight weakness in the cap along the Interstate
64 corridor Thursday evening, with the potential of isolated
The timing of convection still remains somewhat variable Monday
into Tuesday and this variability may not be resolved until it
sampled adequately in the short range guidance.
Temperatures will remain near climatological values given the zonal
flow aloft and the proximity to the baroclinic zone. The 12km NAM,
SREF, and Canadian guidance appeared to provide the most consistent
timing of the shortwaves early in the week and the building of the
ridge by midweek.
Issued at 630 PM CDT FRI AUG 29 2014
Showers and storms will continue to make it into southeast Missouri
this evening...but they will be moving into more stable air as they
approach the Mississippi River. As a disturbance in the upper levels
of the atmosphere approaches our area...the activity will eventually
reach all the taf sites late tonight and Saturday morning.
Instability will be quite weak by that time...so predominantly
showers are expected. Thunder could occur at any time Saturday...but
it was not worth a 12 hour period of thunder in the tafs. Mainly
mvfr vsbys are expected in the more widespread showers...but vsbys
will likely be highly variable since the showers could be heavy.