Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 211154
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
654 AM CDT MON APR 21 2014

.UPDATE...
ISSUED AT 644 AM CDT MON APR 21 2014

UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT MON APR 21 2014

MAIN CONCERN IN THE SHORT TERM IS THE CONVECTION CURRENTLY OCCURRING
ACROSS THE AREA... AND HOW IT WILL EVOLVE THROUGH THE MORNING HOURS.
LATEST SURFACE ANALYSIS SHOWS A TIGHT DEWPOINT GRADIENT FROM WEST
CENTRAL MINNESOTA THROUGH WEST CENTRAL WISCONSIN... ACTING AS A WARM
FRONT OF SORTS... WITH THE THERMAL GRADIENT A BIT FARTHER NORTH AND
ALSO TO THE WEST ALONG THE SURFACE TROUGH. SPC MESOANALYSIS MUCAPE
SHOWS VALUES OF 250-500 J/KG COINCIDENT WITH THE AREA OF ACTIVITY
CURRENTLY OVER THE AREA... LINING UP FAIRLY WELL WITH THE RAP
ANALYZED 850MB THETA-E RIDGE AHEAD OF THE SURFACE FRONT AND
SHORTWAVE APPARENT IN WATER VAPOR IMAGERY. THINGS ARE EXPECTED TO
CONTINUE TO SHIFT EAST THIS MORNING... WITH MOST OF THE ACTIVITY
EAST OF THE FORECAST AREA AFTER 15Z. HOWEVER... UNTIL THAT TIME WE
WILL SEE SOME LOCAL DOWNPOURS AND PEA-SIZED HAIL WITH THE STORMS
THAT ARE MOVING THROUGH THE AREA. BY 18Z WE SHOULD SEE CLEARING
QUICKLY WORKING ITS WAY FROM WEST TO EAST ACROSS THE FORECAST
AREA... WITH STRONG NORTHWEST WINDS... PARTICULARLY OVER WEST
CENTRAL AND SOUTH CENTRAL MINNESOTA. THE COMBINATION OF STRONG WINDS
AND RELATIVE HUMIDITY VALUES IN THE 20S THIS AFTERNOON WILL RESULT
IN ELEVATED FIRE DANGER POTENTIAL FOR FROM WEST CENTRAL INTO SOUTH
CENTRAL MINNESOTA... SO WILL CONTINUE THE FIRE WEATHER WATCH FOR
THAT AREA. HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT... WITH
WINDS QUICKLY DYING OFF DURING THE EVENING HOURS... AND COOLER
TEMPERATURES MOVING BACK INTO THE AREA... MAKING FOR LOWS IN THE 30S
AND PERHAPS BELOW FREEZING IN OUTLYING AREA.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT MON APR 21 2014

TRENDS IN THE LONG TERM CONTINUE TO INDICATE A FAIRLY ACTIVE
MIDWEEK...FOLLOWED BY A COOLING TRNED THAT WILL LAST THROUGH NEXT
WEEKEND.

HIGH PRESSURE BEGINS THE LONG TERM FOR TUESDAY. IT SHOULD BE A
RATHER PLEASNT DAY WITH LIGHT WINDS...AND MILD TEMPERATURES.

THE NEXT WESTERN CONUS TROUGH DIGS SOUTHEAST AND BEGINS TO AFFECT
THE AREA LATE TUESDAY NIGHT. RETURN FLOW AND LLJ INTENSIFIES
OVER THE EASTERN DAKOTAS LATE TUESDAY NIGHT. THIS WILL DEVELOP AT
LEAST SOME WIDELY SCATTERED CONVECTION IN THE EASTERN
DAKOTAS...SPILLING EAST INTO WEST CENTRAL MN LATE. STEEPER LAPSE
RATES MOVE INTO THE WEST DURING THE DAY WEDNESDAY...WITH THE
THREAT OF ISOLATED CONVECTION EXPECTED. THE MORNING ACTIVITY WILL
SPREAD EAST INTO WESTERN WISCONSIN WITH REDEVELOPMENT AGAIN TO THE
WEST INTO THE AFTERNOON. THE BETTER INSTABILITY WORKS EAST WITH
TROUGH WEDNESDAY NIGHT INTO THURSDAY.  AREA OF STEEP LAPSE RATES
LIFT NORTH ACROSS AT LEAST THE SOUTHERN HALF OF THE AREA AHEAD OF
THE SURFACE LOW WHICH IS PROGGED TO MOVE SOUTH OF THE CWA...ALONG/NEAR
THE MN/IA BORDER. STILL SEE SOME ELEVATED HAIL POSSIBILITIES LATER
WEDNESDAY NIGHT AND THURSDAY MORNING.

MODEL DISCREPANCIES REMAIN AS TO HOW QUICKLY THE UPPER LOW MOVES
EAST OF THE AREA. THE 00Z ECMWF IS MOST PROGRESSIVE WITH THE SYSTEM
AND DROPS SOME COLDER AIR SOUTH OVER THE AREA INTO THE WEEKEND.
THE 00Z GFS IS SLOWER AND MUCH MORE AMPLIFIED WITH THE SYSTEM. IT
EVENTUALLY DROPS 85H TEMPERATURES CLOSE TO MINUS 12C ONCE AGAIN BY
SATURDAY MORNING. THIS MAY BE OVERDONE...BUT IT DOES APPEAR WELL
BELOW NORMAL TEMPERATURES ARE ONCE AGAIN IN STORE WELL INTO THE
WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON APR 21 2014

WITH THE EXCEPTION OF THE ACTIVITY CURRENTLY MOVING THROUGH THE
AREA... THE FORECAST PERIOD LOOKS FAIRLY QUIET WITH VFR
CONDITIONS. STRONG NORTHWEST WINDS BY LATE THIS MORNING THROUGH
THIS AFTERNOON WILL BE THE ONLY OTHER ITEM OF NOTE. LATEST SURFACE
ANALYSIS SHOWS COLD FRONT THROUGH ABOUT HALF OF THE AREA... AND
CURRENT TRENDS AND LATEST RAP SHOW IT MOVING THROUGH THE REMAINDER
OF THE AREA BY THE END OF THE MORNING. THIS WILL WORK TO PUSH THE
PCPN OUT AND ALLOW SUNSHINE TO BECOME PREVALENT FROM WEST TO EAST
DURING THE MORNING HOURS. THERE ARE SOME LOW CLOUDS TRYING TO DROP
SOUTH THROUGH NORTH DAKOTA AT THE CURRENT TIME... AND INDICATIONS
ARE THAT THEY SHOULD MAKE IT TO NEAR KAXN BEFORE THEY ERODE AND
STOP THEIR FORWARD PROGRESS. OTHERWISE... LOOK FOR SURFACE RIDGING
TO STEADILY BUILD LATER TODAY INTO TONIGHT... WHICH WILL WORK TO
KNOCK DOWN THE WINDS DURING THE EVENING HOURS.

KMSP...MAIN UNCERTAINTY IS IN THE FIRST HOUR OR TWO OF THE
FORECAST AND WHETHER ANY ADDITIONAL SHRA AND/OR THUNDER MANAGES TO
IMPACT THE AREA. THERE ARE A COUPLE OF LONE SHRA STILL TO THE WEST
RIGHT ALONG THE EXTENSION OF THE UPPER WAVE AND A SECONDARY
SURFACE BOUNDARY ASSOCIATED WITH THE COLD FRONT. ALLOWED FOR A
VCSH THROUGH 1330Z TO ACCOUNT FOR THIS POSSIBILITY. OTHERWISE... WE
SHOULD SEE VFR CONDITIONS WITH GENERALLY SKC AFTER 16Z. NORTHWEST
WINDS WILL GUST AOA 25 KT FOR MUCH OF THE AFTERNOON BEFORE DYING
OFF THIS EVENING AS THE SURFACE HIGH MOVES INTO THE AREA.

/OUTLOOK FOR KMSP/
TUESDAY AFTERNOON...VFR. VARIABLE WIND 5 KT OR LESS BECOMING
SOUTHEAST 5 TO 10 KT.
TUESDAY NIGHT AND WEDNESDAY...MVFR CEILINGS EXPECTED WITH MVFR
VISIBILITIES POSSIBLE ALONG WITH A CHANCE OF RAIN. SOUTHEAST WIND
10 TO 20 KT WITH HIGHER GUSTS.
WEDNESDAY NIGHT...MVFR CEILINGS AND VISIBILITIES EXPECTED... IFR
POSSIBLE WITH RAIN LIKELY. SOUTHEAST WIND 15 TO 20 KT.
THURSDAY...MVFR CEILINGS AND VISIBILITIES EXPECTED EARLY WITH A
CHANCE OF RAIN. SOUTH WIND 10 TO 20 KT SHIFTING WEST.
THURSDAY NIGHT...VFR. WEST WIND 5 TO 15 KT.
FRIDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF
RAIN. WEST WIND 5 TO 15 KT BECOMING NORTHWEST.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS
     EVENING FOR MNZ047-054>056-064-065-073>075-082-083-091-092.

WI...NONE.
&&

$$

UPDATE...
SHORT TERM...TRH
LONG TERM...DWE
AVIATION...







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