Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 270940
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
340 AM CST FRI NOV 27 2015
.SHORT TERM: (Through Tonight)
Issued at 253 AM CST Fri Nov 27 2015
Focus continues to be precip chances and amounts. Late tonight,
focus turns to winter p-types. No changes to the Flood Watch at this
Cdfnt continues to slowly push swd thru the area early this morning.
Expect this fnt to continue to slowly sink swd and shud be along the
sern CWA boarder around 00z this evening. Mdls are in good agreement
regarding mass fields thru the period. However, there are some
differences regarding how quickly precip will shift swd.
Latest guidance suggests another wave of precip will push nwd into
the area this evening/overnight, which may push precip nwd again.
While some pockets of rain may push further nwd, believe the bulk of
the precip will remain across the srn half or so of the CWA.
Focus shifts to cold temps pushing into the region behind the fnt.
At most sites across the CWA, the max temp has already occurred. Some
areas across ern portions of the CWA may rise a degree or two yet
early this morning. Otherwise, expect temps to fall thru the day.
Temps across the CWA are expected to remain above freezing today,
perhaps not by much. However, freezing temps are expected to filter
into nrn portions of the CWA late tonight. Have continued mention of
FZRA late tonight into Sat morning. Still have not mentioned ice
accum across this area as low chance of occurrence and warm ground
temps shud prevent icing.
.LONG TERM: (Saturday through Thursday)
Issued at 339 AM CST Fri Nov 27 2015
(Saturday through Sunday)
Mdls are in fairly good agreement thru this period. However, the
latest NAM ejects the upper low into the Plains earlier than the
consensus, resulting in a deeper low forming over the area and
cooler temps aloft. This soln has not been accounted for in the
A few changes to the prev forecast were made. First, low level
thermal fields are once again warmer than yesterday. Have therefore
trended min temps for Sat and Sun night warmer. This will eliminate
the threat for FZRA as long as this trend continues. Mdls continue
to bring what appears to be the remnants of Hurricane Sandra into
the area on Sun into Sun night. Have raised PoPs across much of the
area to account for this soln.
(Monday through Thursday)
Mdl consensus now develops a sfc low further NW across the Plains.
This results in sly flow early in the period across the region. The
GEM continues to be an outlier and have once again disregarded this
soln. Have also once again therefore trended temps twd a GFS/ECMWF
compromise. Still appears that all precip will be out of the region
by Tues with the remainder of the forecast being dry.
.AVIATION: (For the 06z TAFs through 06z Friday Night)
Issued at 1145 PM CST Thu Nov 26 2015
FROPA has occurred over the last hour at both KCOU and KUIN, which
produced an immediate drop of cigs below 1000 feet, with a dip in
vsbys at KUIN into MVFR cat. Expect IFR cigs to hold tough
at these locations overnight and into at least Friday morning.
MVFR vsbys in moderate to occasionally heavy rain also expected
overnight, with a slow improvement on Friday morning as the
heaviest rain shifts to the south. Meanwhile, STL Metro will
remain in the warm sector for several more hours with VFR cigs aoa
5kft as pre-frontal showers slowly work in from the west, with
LLWS potential due to winds just off the surface in the 40-50kt
range. However, based on latest RUC guidance expect FROPA in the
11-13z time frame, with a rapid drop in conditions much as KCOU
and KUIN experienced between 04-05z. IFR cigs and MVFR vsbys
expected for much of the day on Friday.
Specifics for KSTL: Expect VFR cigs for several more hours as
pre-frontal showers gradually work into the area. Looking for a
rapid deterioration in conditions around 11z as strong cold front
pushes through the TAF area, with cigs immediately dropping into
the 400-700 ft range, with MVFR vsbys in moderate to heavy rain.
Expect IFR cigs and MVFR vsbys to persist for much of the day on
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 52 39 42 39 / 100 90 60 50
Quincy 38 34 39 34 / 80 30 20 30
Columbia 39 34 37 36 / 100 70 50 50
Jefferson City 40 35 38 36 / 100 80 60 50
Salem 60 42 44 40 / 100 100 70 60
Farmington 59 39 42 39 / 100 100 80 70
MO...Flood Watch through Saturday morning FOR Crawford MO-Franklin MO-
Jefferson MO-St. Charles MO-St. Louis City MO-St. Louis MO-
Flood Watch through Saturday morning FOR Iron MO-Madison MO-
Reynolds MO-St. Francois MO-Ste. Genevieve MO.
Flood Watch through late tonight FOR Audrain MO-Boone MO-
Callaway MO-Cole MO-Gasconade MO-Lincoln MO-Moniteau MO-
Montgomery MO-Osage MO-Warren MO.
IL...Flood Watch through Saturday morning FOR Madison IL-Monroe IL-
St. Clair IL.
Flood Watch through Saturday morning FOR Clinton IL-Randolph IL-