National Weather Service Raw Text Product

365 
FXUS63 KLSX 100926
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
426 AM CDT SUN MAR 10 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 358 AM CDT SUN MAR 10 2013

WAVES OF SHOWERS CONTINUE EARLY THIS MORNING WITHIN THE DEEP
LAYERED MOIST SW FLOW ALOFT. THE UPPER LOW NOW OVER WESTERN KS
WILL MOVE ENE TO INTO NW MO BY 00Z WITH A SERIES OF SHORT WAVES
TROFS ROTATING NEWD WITH THE ADVANCING LOW. THE MAIN SHORT WAVE
TROF CURRENTLY STRETCHING THRU WEST TX WILL BECOME NEGATIVELY
TILTED AS A STRONG ULJ ROTATES NEWD INTO THE AREA. LARGE SCALE
ASCENT WILL INCREASE SIGNIFICANTLY FROM LATE MORNING INTO THE
EARLY AFTERNOON IN RESPONSE...AND THIS WILL LEAD TO A SUBSTANTIAL
INCREASE IN THE AREAL COVERAGE OF SHOWERS/RAIN ACROSS MO WITH THE AREA
OF PRECIPITATION THEN SHIFTING EASTARD INTO SW IL DURING THE
AFTERNOON. THE COMBINATION OF PERSISTENT RAINFALL...WITH OCCASIONAL
MODERATE TO HEAVY BURSTS WITH EMBEDDED THUNDERSTORMS...COULD CAUSE
FLOODING PROBLEMS ON SMALLER CREEKS AND STREAMS AND LOW LYING POOR
DRAINAGE AREAS WITHIN THE REGION OF THE SHRINKING SNOW FIELD FROM
CENTRAL AND NE MO INTO WEST CENTRAL IL. A NUMBER OF SMALL RIVERS
WITH FORECAST POINTS ARE ALREADY IN FLOOD. THE CURRENT FLOOD WATCH
HAS THIS AREA OUTLINED WELL. THE UPPER LOW IS FORECAST TO CONTINUE
MOVING NEWD INTO THE UPPER MS VALLEY TONIGHT AS THE TRAILING VORT
MAX AND TROF AXIS SHIFT EASTWARD INTO EASTERN MO. WE COULD STILL
SEE SOME LIGHT SNOW LATE THIS EVENING INTO THE OVERNIGHT
HOURS...PRIMARILY ACROSS NE MO INTO WEST CENTRAL IL AS THE COLD
AIR DEEPENS BUT ANY ACCUMULATIONS WOULD BE RATHER LIGHT. THE
THREAT OF SOME LIGHT SNOW AND FLURRIES WILL PERSIST ON MONDAY
UNTIL THE UPPER TROF AXIS MOVES EAST OF THE CWA DURING THE
AFTERNOON. IT WILL BE A CHILLY DAY WITH GUSTY NORTHWEST WINDS AND
EXTENSIVE STRATUS.

GLASS

&&

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 358 AM CDT SUN MAR 10 2013

A DEEP LONG WAVE TROF WILL EVOLVE OVER THE EASTERN CONUS IN THE
TUES-WED TIME FRAME AS THE INITIAL UPPER TROF MOVES EASTWARD AND A
NW FLOW SHORT WAVE TROF DIGS NEWD. THIS LATER SHORT WAVE WILL
TRAVERSE THE REGION LATE MON NIGHT INTO EARLY TUESDAY BRINGING A
REINFORCING SHOT OF COLDER AIR. THE COLD AIR DOESNT LOOK LIKE IT
WILL HANG AROUND FOR LONG HOWEVER. BY THURSDAY WE SHOULD SEE
TEMPERATURES ON THE RISE AS THE SURFACE HIGH RETREATS AND HEIGHTS
RISE ALOFT. NW FLOW ALOFT WILL PERSIST INTO THE WEEKEND DUE TO BROAD
TROFFING FROM THE NATIONS MIDSECTION INTO THE WESTERN ATLANTIC...HOWEVER
THE HEIGHTS ALOFT AND H85 TEMPERATURES WOULD SUGGEST ABOVE AVERAGE
TEMPERATURES SHOULD PREVAIL.

GLASS

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1045 PM CST SAT MAR 9 2013

A BROAD AREA OF RAIN SHOWERS WITH ISOLATED EMBEDDED THUNDERSTORMS
WILL CONTINUE SPREADING EWD ACROSS MO/IL OVERNIGHT AND TOMORROW.
MVFR/IFR CONDITIONS ARE ANTICIPATED...ESPECIALLY AFTER ONGOING
RAINFALL BEGINS TO SATURATE THE LOWER ATMOSPHERE CAUSING CLOUD
BASES TO DESCEND. IF GUSTY SFC WINDS SUBSIDE TONIGHT THEN THERE
WILL BE A CONCERN FOR LLWS BECAUSE OF THE 50KT LLJ. THERE IS
STILL SOME QUESTION REGARDING WHETHER OR NOT THERE WILL BE A BREAK
IN THE PCPN TOMORROW AFTN WHEN THE DRY SLOT MOVES OVERHEAD. IF
CIGS DO IMPROVE DURING THE AFTN THEN THEY WILL PROBABLY FALL BACK
TO MVFR OR IFR TOMORROW EVENING AS STRATUS DVLPS AND SPREADS
ACROSS THE AREA BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WINDS
REMAIN SLY TO SELY AHEAD OF THE APPROACHING SFC LOW THEN VEER NWLY
LATE IN THE TAF PD AFTER A CDFNT MOVES THROUGH THE AREA.

SPECIFICS FOR KSTL...ISO-SCT SHRA HAVE DVLPD NEAR KSTL AHEAD OF A
BROADER AREA OF RAIN SHOWERS WHICH IS EXPECTED TO MOVE EWD AND
REACH KSTL OVERNIGHT. CONDITIONS WILL PROBABLY DETERIORATE TO
MVFR/IFR LATER TONIGHT. IF GUSTY SFC WINDS SUBSIDE TONIGHT THEN
THERE WILL BE A CONCERN FOR LLWS BECAUSE OF THE 50KT LLJ. THERE
COULD BE A BREAK IN THE PCPN TOMORROW AFTN HOWEVER EVEN IF CIGS DO
IMPROVE THEY WILL PROBABLY FALL BACK TO MVFR OR IFR TOMORROW
EVENING AS STRATUS DVLPS AND SPREADS ACROSS THE AREA BEHIND THE
DEPARTING LOW PRESSURE SYSTEM. WINDS REMAIN SLY TO SELY AHEAD OF
THE APPROACHING SFC LOW THEN VEER NWLY LATE IN THE TAF PD BEHIND A
CDFNT.

KANOFSKY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FLOOD WATCH THROUGH THIS EVENING FOR AUDRAIN MO-BOONE MO-
     CALLAWAY MO-COLE MO-KNOX MO-LEWIS MO-MARION MO-MONITEAU MO-
     MONROE MO-MONTGOMERY MO-PIKE MO-RALLS MO-SHELBY MO.

IL...FLOOD WATCH THROUGH THIS EVENING FOR ADAMS IL-BROWN IL-PIKE IL.

&&

$$

WFO LSX