Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 050602
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1202 AM CST Thu Mar 5 2015
Issued at 856 PM CST Wed Mar 4 2015
There is mid-level echo on radar across the southern CWA however
surface dew point depressions are 10-15 degrees and drier air
continues to advect in from the north. A few flurries or perhaps a
brief snow shower cannot be entirely ruled out however the overall
trend is for a continued decrease in precipitation coverage and
intensity tonight. Updated grids and products (including winter
headlines) have been sent to reflect these changes.
.SHORT TERM: (Through Tonight)
Issued at 217 PM CST Wed Mar 4 2015
All of the precipitation has changed to snow over our forecast area.
As of 20z, heaviest band of snow has setup along a line from
Reynolds County MO to Randolph County IL, in the warning area.
Upwards of two inches has fallen in this area so far with lesser
amounts to the north. With decent lift as next shortwave slides east
northeast through southern MO, will see another 2 to 3 inches, maybe
a bit more, before snow tapers off late this evening. Storm totals
in our far south still look to be between 3 to 6 inches. For now
will keep all headlines going. Otherwise, for areas north of I-44 in
MO and I-70 in IL, it will be dry with skies remaining mostly
cloudy overnight. As for low temps, single digits far north to the
mid teens far south.
.LONG TERM: (Thursday through Next Wednesday)
Issued at 217 PM CST Wed Mar 4 2015
(Thursday through Saturday)
Sfc ridge will continue to build into the region Thurs with NW flow
aloft. Based on upstream obs over ND/SD, have trended cloud forecast
twd the more cloudy NAM/Local WRF for Thurs. Expecting high level
clouds to pull sewd out of the region during the morning, with CU
developing during the late morning into afternoon. Based on progd
soundings across the region, any CU that develops has the potential
for flurries. While going forecast contains more cloud cover than
previously, have kept temps for Thurs as-is as breaks in clouds shud
help temps warm.
Otherwise, little change to prev forecast thru Sat as prev forecast
still appears on track.
(Sunday through Wednesday)
Not much change to the prev forecast. Mdls are in rather good
agreement overall. NW flow aloft dominates the extd and lacks any
noteworthy trof. That said, a weak s/w and associated sfc cdfnt pass
to the NE of the region late Sat which shud be monitored for future
shifts in track.
Overall, no precip expected thru the period with temps that
gradually warm thru the period with above seasonal average temps by
Sun and into next week.
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1146 PM CST Wed Mar 4 2015
Mid/high clouds assoc with a winter storm affecting areas from TX
northeast into the OH vly will begin to thin out as it streams NE
overnight exiting the area by 12Z. A batch of VFR CIGs is dropping
south from ern IA and NW IL. There are pockets of MVFR CIGs and
an isld IFR report. These are the clouds hinted at by guidance
earlier in the day. Confidence remains fairly low on
heights...areal coverage and timing of these clouds. A few hour
window of lght/vrb or SE winds is tracking SE thru NE MO and w
cntrl IL with winds returning to the N/NW behind this feature thru
00Z...eventually becoming lght/vrb once again Thu evng as the sfc
ridge passes. Sthrly flow commences after 6Z Fri.
Specifics for KSTL:
VFR fcst thru the prd. 3-5kft CIGs dropping south along the MS
rvr possibly impacting the terminal after 9Z.
MO...WINTER STORM WARNING until Midnight CST tonight FOR Iron MO-
Madison MO-Reynolds MO.