Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 272133
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
333 PM CST FRI NOV 27 2015
.SHORT TERM: (Through Saturday)
Issued at 333 PM CST Fri Nov 27 2015
A strong wound-up storm system over the Great Basin region of the
western CONUS is expected to move little during this period,
maintaining an active southwest flow aloft over our region, with
disturbances training along. This will all intersect a pretty moist
airmass in place still over our region and result in high probs for
precipitation, especially for areas near and south of the I-70
First, will keep the FFA going as-is. Despite rain tapering off in
central and now east-central MO, the rain is cycling to an extent
and should try to fill back in further north into central MO this
evening and overnight. Also, flooding effects are typically
delayed from when the rainfall occurs and so the flood threat does
not end right when the rainfall tapers. Will let the evening and
overnight shifts re-evaluate and cancel early as needed once the
effects on the area are better realized.
Second, surface temps will once again approach the freezing mark
across parts of northeast MO and west-central IL and with current
and expected vertical temp profiles, would be supportive of a brief
period of light freezing rain or sleet. Fortunately, much of the
threat for measurable pcpn will be south of this area and any
amounts, should they occur, should be very light. PoPs here are
Preferred the higher end of MOS temps for mins tonight and lower end
of MOS for maxes Saturday with extensive cloud cover in place.
.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 18z TAFs through 18z Saturday Afternoon)
Issued at 1031 AM CST Fri Nov 27 2015
Slow moving cold front has finally moved just south of CPS. Light
to moderate intensity rain will continue at the taf sites this
afternoon, then likely shift south of UIN this evening while
becoming light in COU. Do not see much change in the cig heights
remaining around to a little below 1000 feet, except there should
be some improvement in UIN, especially Saturday morning. Northerly
surface winds wil continue through the period.
Specifics for KSTL: Persistent light to moderate intensity rain
will continue through most of the period, possibly finally ending
Saturday afternoon as the cold front shifts further southeastward.
Little change in the cig height is expected, remaining just below
1000 feet. There may be a little improvement in the ceiling
Saturday afternoon. A northerly wind will continue through the
MO...Flood Watch through Saturday morning FOR Crawford MO-Franklin MO-
Iron MO-Jefferson MO-Madison MO-Reynolds MO-St. Charles MO-
St. Francois MO-St. Louis City MO-St. Louis MO-Ste.
Genevieve MO-Washington 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 Clinton IL-Madison IL-
Monroe IL-Randolph IL-St. Clair IL-Washington IL.