Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 010912
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
312 AM CST Sun Dec 1 2013
.SHORT TERM...(Today through Tuesday)
ISSUED AT 312 AM CST Sun DEC 1 2013
Current surface analysis shows a weak frontal boundary to our
northwest. Low level moisture has been on the increase ahead of this
feature and low level clouds have developed. This front will sag
southeast into the area today...and end up stalling out over the
region. Low pressure develops on the front in southeastern OK by 06Z
Monday...which moves east and tends to dissipate as it does so.
Meanwhile, the front over our region tends to lose its identity by
Monday afternoon and starts to move north as a warm front.
With the amount of low level moisture and the weak front in the
vicinity today through Monday afternoon, expect mainly mostly cloudy
skies. Still toying around with the idea of some drizzle tonight
into Monday morning and the possibility of fog. SREF ceiling
height/vsby ensemble probabilities support this idea mainly late
tonight. Some of the higher resolution models are also indicating
the possibility of very light precipitation later tonight into
Monday morning...in association with a weak short wave aloft.
Temperatures will be tricky today as was expected a few days
ago...given the lack of confidence on the extent of cloud cover. The
06Z RAP/NAM indicate pretty heavy cloud cover. We will generally
stay in the lower to mid 50s...unless we are able to obtain more
sunshine. Mondays high should be in the same ballpark as today`s - in
the 50s, although the models are showing winds becoming south across
the entire area and warmer air advecting in, as the front begins
moving north. In fact, the 00Z MET guidance is showing low 60s
across the southern zones. Will stay in the 50s for now...but
will definitely be higher than todays highs.
Things should stay dry for Monday night and Tuesday as we await the
arrival of our next system, which models have definitely sped up
with recent runs. The GFS wants to produce precipitation over the
area as early as Tuesday another front is knocking our western
doorstep. The NAM and Euro has also sped up but not as fast as the
GFS so will maintain a dry forecast for Mon night - Tuesday.
However, we will raise temps for Tuesday into the 60s given this
.LONG TERM...(Tuesday through Saturday)
ISSUED AT 254 PM CST SAT NOV 30 2013
Forecast confidence has decreased in the extended forecast...esp
as we had into the wed through Fri time frame, as operational
model spread continues to increase with the timing/handling of a
strong system that will be tracking across the country.
After a period of h50 ridging Tue...chances for light rain will
begin to increase Wed/wed night as moist sw flow aloft develops
ahead of a highly amplified trof digging into the western states.
However...it still looks as though appreciable rainfall will likely
hold off until this trof spawns a sfc low over the srn plains Thu
and then tracks up a frontal boundary Thu night.
The latest 12z GFS now suggests this boundary will come through the
forecast area on Wed...while the 12z ECMWF does not bring it through
until Thu...about 24 hours later. The GFS then maintains a
progressive system and takes the front on to the Appalachians, while
the euro wants to hang it up in the Oh Valley for 12 hours or so
(thus is warmer and keeps significant precip in our area longer).
Our current forecast is somewhat of a compromise of these solutions,
so will try to make as little changes as possible to the timing of
cold air and possible transition period to some type of
freezing/frozen precip at the end of the event. Our confidence is
too low right now to even speculate on details.
One thing that seems more sure is that we will probably get another
shot of arctic air after this system departs toward the end of the
extended forecast period.
ISSUED AT 312 AM CST SUN DEC 1 2013
Latest satellite loop shows low level clouds continuing to form
but all VFR attm. Some drizzle and mvfr cigs/vsby possible for a
few hours in the morning but expect cigs to come back up during the
day. Some additional drizzle or light rain will be possible
tonight, with lowered cigs/vsbys again probable.