Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 052308
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
608 PM CDT Tue May 5 2015
.SHORT TERM: (Through Late Tonight)
Issued at 250 PM CDT Tue May 5 2015
Isolated to scattered afternoon SHRA/TSRA should start to dissipate
early tonight with the loss of diurnal heating. Overnight lows in
the 60s across the CWA will be fairly similar to last night. Winds
will start to back and become more southerly overnight in response
to a low pressure system which will be lifting from NM into the
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 250 PM CDT Tue May 5 2015
Southwest flow aloft can be expected with southerly surface flow
thru the upcoming weekend. This nearly always alludes to above
average temps and pcpn chances and it appears it will be no
different this time around.
Thanks to hi-height SW flow initially, upper level disturbances will
deliver glancing blows to our region from the west and north
Wednesday and Thursday, resulting in decent rain chances for a
UIN-COU axis but minimal chances (climo [30%] or below) elsewhere.
The heights start to edge downward and enable the train of upper
level disturbances to start affecting more and more real estate over
our region by Friday and into the weekend, and this will represent
our best chances for widespread rain, where all areas will have
above climo PoPs with many in likely category. This is not a huge
change by any stretch from the previous forecast, however.
The main upper level LOW that had been spinning over the
southwestern CONUS for much of this week is anticipated to bust
loose into the Plains by early next week and affect our region on
Monday, giving us one more day of potentially wet wx.
Finally by Tuesday a pattern change is in the works with NW flow
aloft in the wake of that main storm system exiting the SW CONUS.
Max temps thru Thursday are expected to be in the 80s with min temps
in the 60s, with a gradual cooling trend from the west beginning
Friday, but most locales in STL metro and east should still break 80
thru the weekend until early in the work week.
A more definitive cooling trend is then expected to take hold on
Tuesday and continue for a few days beyond.
.AVIATION: (For the 00z TAFs through 00z Wednesday Evening)
Issued at 544 PM CDT Tue May 5 2015
The high based, diurnal cumulus clouds along with the widely
scattered showers and thunderstorms should dissipate early this
evening due to the loss of daytime heating. There may be a little
mid-high level cloudiness for the remainder of the night into
Wednesday morning. At least scattered cumulus clouds will develop
again late Wednesday morning and afternoon with the best chance of
showers/storms for the COU area. S-sely surface winds can be
expected tonight with a sly surface wind on Wednesday.
Specifics for KSTL: Looking at the latest radar trends it appears
that the widely scattered showers/storms will not impact STL early
this evening. This diurnal convective activity along with the
high based cumulus clouds should dissipate later this evening with
just a little mid-high level cloudiness for the remainder of the
night into Wednesday morning. Diurnal cumulus clouds will develop
again for late Wednesday morning and afternoon, but it appears
that any showers/storms will remain west of STL. A weak s-sely
surface wind can be expected tonight with a strengthening sly wind
for Wednesday morning into the afternoon.
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 66 86 66 87 / 20 10 5 30
Quincy 63 83 64 83 / 20 30 20 60
Columbia 62 81 63 82 / 20 50 10 60
Jefferson City 61 82 63 82 / 20 40 10 60
Salem 63 84 61 85 / 20 5 5 10
Farmington 60 81 61 83 / 20 5 5 30