Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 181835
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
135 PM CDT Fri Jul 18 2014
.SHORT TERM...(Tonight through Sunday night)
Issued at 135 PM CDT FRI JUL 18 2014
Rains stayed basically to our south, so in hindsight, the NAM was
essentially useless, as the other models resolved much better the
farther south track of better moisture and precip over the past
few days. Will continue to side with a ECMWF/GFS approach through
Sunday. They continue to paint scant QPF over the Pennyrile region
and east tonight through the weekend, probably more diurnal in
nature Sat/Sun. Kept a token slight chance PoP over there. Most
areas will remain dry. And, we have it dry west of there. Some
cloud cover will hang around given the slow movement of the trof,
and model time sections revealing abundant low level moisture.
Thought about a fog inclusion in at least the grid forecast. But
confidence not high enough yet, given potential cloud cover. Could
be some, thus we will update if need be. Temps will continue to be
a blend of weighted model guidance and persistence.
.LONG TERM...(Monday through Thursday)
Issued at 303 AM CDT FRI JUL 18 2014
The large model differences concerning the strength and location of
upper level troughing over the eastern states have narrowed with the
00z model suite. The 00z gfs and ecmwf are in reasonable agreement
now...and they are in line with the consistent ecmwf ensemble mean.
The 00z gfs ensemble mean is not part of the consensus of the other
Based on the 00z model consensus...it appears that the western U.S.
ridge will expand eastward across the Plains and Ohio Valley on
Monday and Tuesday. The trend toward stronger upper level ridging
translates to higher temps and lower pops in the deterministic model
mos guidance. Some isolated afternoon convection is still possible
in the hot and unstable air mass...but overall Monday through
Tuesday should be mainly dry.
Wednesday and Wednesday night appears to be the time frame when a
500 mb shortwave will dig southeast across the Great Lakes into the
Ohio Valley. Both the 00z gfs and ecmwf are rather impressive with
the strength of this shortwave. Pops will be somewhat higher as this
shortwave approaches...but still only in the chance category.
On Thursday...the models indicate a cold front associated with the
shortwave will make it into the Lower Ohio Valley. There is quite a
bit of variability concerning the strength and timing of the front.
The forecast will keep the chance pops going into Thursday with
temps cooling off a few degrees.
Issued at 1138 AM CDT FRI JUL 18 2014
Upper low moving across the area accompanied by mid/high clouds that
will continue to progress east this afternoon. Light/variable
winds should become east and increase to 5-8kts or so this p.m.
Tonight winds will become near calm. Skew-Ts indicate abundant low
level moisture after 06z, and a possibility of low cloud light fog
development. Continued with our inclusion with slight adjustments
in generally the low end MVFR range, maybe briefly IFR. MOS guidance
supports this as well. However it spells out, conditions should
improve Saturday morning.