Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 260859
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
259 AM CST Fri Dec 26 2014
.SHORT TERM...(Today through Sunday night)
Issued at 251 AM CST FRI DEC 26 2014
Today will be warm/mild and pleasant, as High pressure anchors
over the Southeast. Return flow slys will be the only damper on
temps that will be climbing into the 50s for highs.
The return flow will also pump some moisture back into the column,
as a developing weather system takes shape to our west. It moves
in from the west later tonight, and especially on Saturday. Pops
will spike in the high likely to categorical range Saturday into
Saturday night, mainly across southern counties, as the broad
carving of the mean long wave trof occurs across Tx. This keeps
the warm/moist fetch wide open thru the weekend as the surface
system makes passage Saturday, but overrunning rains continue into
With the surface lows ejecting out of the mean long wave trof
taking a track south and east of the PAH FA, thunder chances
should likewise stay south and east of us. However, some elevated
instability does exist in the form of Total Totals near 50, and
K`s into the 30s. It`ll be something to watch for, but not include
any thunder mention in the forecast, as again, it should stay
primarily south and east of us.
Storm system QPF will be highest (about 3/4") in our southeastern
counties, tapering to about a quarter inch in our northwestern
counties. By the time the column starts to cool enough for a
changeover, the pcpn is drawing to an end late Sunday into Sunday
night, so nothing is forecast other than liquid pcpn for this event.
.LONG TERM...(Sunday through Thursday)
Issued at 206 PM CST THU DEC 25 2014
The 12z ECMWF and GFS are in good agreement through mid week, and
have been followed closely. They resemble the consensus derived on
yesterday`s shift. The prior consensus was, and current depiction
is, staring 12z Sunday, a shortwave forecast to be over TX, with SW
flow aloft over our area, and a strong jet punching SSE out of west
Canada into the Pacific NW. The TX shortwave is still forecast to
dampen out as it heads NE toward and eventually into the TN valley
region by Sunday night.
Meanwhile, out west, as the jet energy continues to dig SSE, a
closed low is forecast to form somewhere around California or
slightly east into the intermountain west. The pattern will evolve
into a split flow regime by mid week, as the low closes off and
heads for AZ, while shortwave energy moves through a broad trof
about an upper low near Hudson Bay, across the Great Lakes region
and Northeast. This will turn our upper flow more WNW with time as
the system out west triggers shortwave ridging over the south
The resultant weather. The models push precip out more quickly on
Sunday. Will only carry a morning chance, with the afternoon dry
(rain). PoPs were removed for Sunday night, and taken back out for
Monday as well, with no features to key in on, and deeper layer
drying working in from the WSW.
Dry Tuesday through Wednesday night as well. Will keep an eye on the
models depiction of some moisture trying to work south toward the
area. But it seems to fizzle encountering mid level confluence
between the two systems described above. Otherwise arctic high
pressure will continue to settle southeast, centered over the
Plains by mid week.
Many question marks exist for Thursday and Thursday night.
Significantly cut back the moderate chance Pops to just slights for
now given such low confidence, despite what model blending does.
The 12z runs, show nothing at all for Thursday. In fact the ECMWF
never brings precip into the area at all through Thursday night,
whereas the GFS breaks down the shortwave ridge and allows a moist
SW flow to develop, with precip possible Thursday night. Prior runs
of the ECMWF were more aggressive bringing moisture and possible
precip north into the area. Too many question marks to go with
anything more than slights (20 percent) for now. Will also use
simplistic R-/S- wording.
Temperatures throughout were a blend of MOS/Ensemble MOS and
Issued at 251 AM CST FRI DEC 26 2014
High clouds will stream in today and lower and thicken as we move
toward evening and a weather system approaches from the west. Pcpn
chances for terminals should hold off til Saturday. Slys may pick
up and gust thru the teens at times this pm.