Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 071729
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1229 PM CDT MON JUL 7 2014

.UPDATE...
ISSUED AT 1216 PM CDT MON JUL 7 2014

UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT MON JUL 7 2014

AMPLIFICATION OF THE BROAD CYCLONIC UPPER FLOW OVER THE NORTH
CENTRAL CONUS WILL OCCUR DURING THE SHORT TERM FORECAST PERIOD. A
MID LEVEL SHORTWAVE TROUGH WAS NOTED ON EARLY MORNING WATER VAPOR
IMAGERY OVER SOUTHERN SASKATCHEWAN AND NORTH DAKOTA. THIS FEATURE
WILL DIP ACROSS THE AREA TODAY AND TONIGHT. EXPECT SOME OF THE
ATTENDANT SHOWER AND THUNDERSTORM ACTIVITY TO MOVE INTO
WEST/CENTRAL MN THIS MORNING. SAID ACTIVITY SHOULD BE SOMEWHAT
SCATTERED IN COVERAGE...BUT THEN EXPECT MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS TO BLOSSOM THIS AFTERNOON AS THE AFOREMENTIONED
SHORTWAVE ARRIVES.

WHILE THERE IS NOT A SURFACE COMPONENT TO THIS TROUGH IN OUR
AREA...SHEAR AND INSTABILITY PARAMETERS STILL APPEAR SUFFICIENT TO
SUPPORT SEVERE STORMS THIS AFTERNOON...PER PROGGED BULK SHEAR VALUES
OF 50-60 KTS...ML CAPES AROUND 1500 J/KG...AND 700-500MB LAPSE RATES
OF 7 C/KM. LARGE HAIL WILL LIKELY BE THE PRIMARY THREAT...WITH
DAMAGING WINDS ALSO A CONCERN AS THE STORMS POTENTIALLY EVOLVE INTO
A COMPLEX.

BREEZY WEST SOUTHWEST WINDS TODAY SHOULD EVOKE SUFFICIENT
MIXING...WITH NEAR NORMAL HIGHS NOT STRAYING TOO FAR AWAY FROM THE
80 DEGREE MARK. CLOUDS GRADUALLY SCATTER OUT TONIGHT FROM WEST TO
EAST IN THE WAKE OF THE STORM...WITH LOWS IN THE UPPER 50S TO LOWER
60S ANTICIPATED.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 308 AM CDT MON JUL 7 2014

OVERALL A PROGRESSIVE PATTERN WILL CONTINUE IN THE EXTENDED PERIOD
WITH EVERY TWO/THREE DAYS A FRONTAL BOUNDARY/SHRTWV AND ASSOCIATED
AREA OF PRECIPITATION IS EXPECTED ACROSS THE UPPER MIDWEST. TIMING
ISSUES WILL REMAIN...ESPECIALLY LONGER IN THE EXTENDED PERIOD YOU
GO. YESTERDAYS FIRST 90 DEGREES AT THE TWIN CITIES AIRPORT WILL
LIKELY BE THE LAST FOR THE NEXT WEEK AS THE MEAN PATTERN REMAINS
NW. THICKNESS VALUES HAVE TRENDED COOLER FOR TUE/WED OF THIS
WEEK...SO TEMPS MAY BE A FEW DEGREES COOLER THAN EXPECTED. EVEN
WITH FULL SUNSHINE ON WEDNESDAY...TEMPS MAY ONLY REACH THE MID TO
UPPER 70S. TUESDAY WILL HAVE CYCLONIC FLOW BEHIND TODAYS SYSTEM
WHICH WILL ALLOW FOR INSTABILITY SHRA/TSRA TO REDEVELOP DURING THE
DAYTIME. HOWEVER...TYPICALLY THESE INSTABILITY SHRA/TSRA ARE ISOLD
WITH THE GREATEST CONCENTRATION CLOSER TO THE CENTER OF THE UPPER
LOW WHICH WILL BE NORTH OF THE GREAT LAKES. WC/NW WI WILL HAVE THE
BEST CHC OF THESE SHRA/TSRA TUE AFTN. THE NEXT FRONTAL BOUNDARY
IS EXPECTED TO IMPACT THE REGION LATE THURSDAY/EARLY FRIDAY BASED ON
THE CURRENT MODEL TRENDS. ONCE AGAIN BEHIND THIS SYSTEM...COOLER
THAN NORMAL TEMPS WILL LIKELY SET UP FOR THE EARLY PART OF NEXT
WEEKEND. AS PREVIOUSLY DISCUSSED...THIS PROGRESSIVE PATTERN WILL
HAVE UNCERTAINTIES ON TIMING. IN ADDITION...SOME OF THE LONGER
RANGE MODELS INDICATED THAT THIS COOLER PATTERN WILL REMAIN ACROSS
THE UPPER MIDWEST THROUGH THE THIRD WEEK OF JULY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1216 PM CDT MON JUL 7 2014

EXPECTATIONS HAVEN/T CHANGED MUCH FROM PREVIOUS FORECASTS... WITH
A PERIOD OF SHRA/TSRA STILL EXPECTED ACROSS THE AREA...
PARTICULARLY IN THE 20-02Z WINDOW. SOME ACTIVITY IS ALREADY
PRESENT ALONG THE NORTHERN PERIPHERY OF THE INSTABILITY
GRADIENT... AND THIS WILL LIKELY CONTINUE TO FESTER THROUGH THE
EARLY AFTERNOON HOURS BEFORE MORE WIDESPREAD AND LIKELY MORE
INTENSE TSRA DEVELOP OVER THE CENTRAL PORTION OF THE AREA IN
RESPONSE TO FURTHER DESTABILIZATION AND FORCING ASSOCIATED WITH
THE SHORTWAVE CURRENTLY SWINGING THROUGH NORTH DAKOTA. ACTIVITY
WILL TRACK EAST ACROSS THE AREA THROUGH EARLY EVENING UNTIL
SUBSIDENCE AND DRIER AIR ARRIVE BEHIND THE SHORTWAVE AND SURFACE
FRONTAL BOUNDARY.

KMSP...CONFIDENCE IN OVERALL TIMING OF BEST CHANCES FOR SHRA/TSRA
IS FAIRLY HIGH... BUT COULD CERTAINLY SEE WINDOWS OF LOWER
CEILINGS AND VISIBILITIES DEPENDING UPON TRACKS AND INTENSITY OF
INDIVIDUAL STORMS. STRONG WIND GUSTS AND HAIL ARE A POSSIBILITY
WITH MODERATE INSTABILITY AND SHEAR... SO THAT WILL ALSO BE A
POTENTIAL REALTIME/NOWCAST ISSUE FROM LATER THIS AFTERNOON INTO
EARLY EVENING.

/OUTLOOK FOR KMSP/
TUESDAY NIGHT...VFR. NORTHWEST WIND 10 TO 15 KT.
WEDNESDAY...VFR. WEST WIND LESS THAN 5 KT.
WEDNESDAY NIGHT...VFR. SOUTH WIND 5 TO 10 KT.
THURSDAY...VFR. SOUTH WIND 5 TO 15 KT.
THURSDAY NIGHT AND FRIDAY...MVFR CONDITIONS POSSIBLE WITH A CHANCE
OF SHRA/TSRA. SOUTH WIND 10 TO 20 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

UPDATE...
SHORT TERM...LS
LONG TERM...JLT
AVIATION...





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