Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 201203
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
703 AM CDT MON APR 20 2015

.UPDATE...
ISSUED AT 647 AM CDT MON APR 20 2015

UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT MON APR 20 2015

SFC ANALYSIS SHOWS A 984MB LOW PRES CENTER OVER NRN MI WITH A
TRAILING N-S CDFNT FROM THE OH RIVER VALLEY THRU THE LWR MISS
RIVER VALLEY. A COUPLE OF SFC TROFS ARE VAGUELY EVIDENT ON WV
SATELLITE IMAGERY ALONG WITH SFC MAP ANALYSIS OVER NRN MN AND WRN
WI ROTATING AROUND THE SFC LOW. ALOFT...A DEEP LONGWAVE TROF WITH
A CUTOFF LOW WITHIN IT WILL DRIVE SEWD INTO THE N-CENTRAL CONUS
WITH THE UPR LOW CENTERING ITSELF OVER THE CENTRAL GREAT LAKES BY
TUE MRNG. THE POINT OF EMPHASIS WITH THESE FEATURES ARE...STRONG
WINDS DUE TO A TIGHT PRES GRADIENT IN THE WAKE OF THE SURFACE
FRONTAL SYSTEM AND THE POTENTIAL FOR -SHRA THIS AFTN UNDERNEATH
THE PASSING UPR LVL LOW. FIRST...WITH RESPECT TO THE WINDS...WINDS
WILL BE FROM THE NORTHWEST THROUGHOUT THIS SHORT-TERM PORTION OF
THE FCST. HOWEVER....H925-H850 WINDS WILL RUN CONTINUALLY 30 KT
ALL DAY...AND WITH MODEST SUBSIDENCE ALONG WITH THE TIGHT PRES
GRADIENT...SFC SUSTAINED WINDS WILL EASILY HIT 20-25KT /ALONG WITH
GUSTS UPWARDS OF 35-40KT/ FOR MUCH OF CENTRAL-SRN MN TDA...
PARTICULARLY LATE THIS MRNG INTO THE EARLY EVE HRS. THEREFORE...
HAVE OPTED TO HOIST A WIND ADVY FOR MUCH OF CENTRAL- SRN MN. THE
SECOND POINT WILL BE ISOLD-SCT RAIN SHOWERS THIS AFTN THRU THIS
EVE AS THE UPR LOW MOVES ACRS. STEEP LOW-MID LVL LAPSE RATES MAY
WELL BE EFFICIENT ENOUGH TO PRODUCE SLEET/GRAUPEL UNDER ANY
STRONGER CELLS WITH THE COLD CORE LOW ALOFT. AS THE UPR LVL LOW
SETTLES INTO WI TNGT...CONTINUED CAA WILL DROP LOWS TO THE
FREEZING MARK FOR NRN AND ERN PORTIONS OF THE CWFA. WITH CHCS FOR
ISOLD-SCTD PRECIP CONTINUING OVERNIGHT THRU TUE MRNG...THERE IS A
SMALL CHANCE FOR SOME OF THE SHOWERS TO MIX WITH AND CHANGE OVER
TO -SN BY DAYBREAK. IF ANYTHING...A COUPLE TENTHS OF SNOW
ACCUMULATION MAY BE POSSIBLE ON GRASSY AREAS NORTH OF THE I-94
CORRIDOR. REGARDING TEMPS...A MUCH COOLER DAY IS ON TAP WITH
WIDESPREAD STRATUS COVER AND CAA CONTINUING UNDER NW FLOW ALOFT.
HIGHS TDA WILL ONLY HIT THE MID-UPR 40S WITH LOWS TNGT DROPPING TO
THE LOW 30S.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 318 AM CDT MON APR 20 2015

LITTLE CHANGE TO THE LONG TERM FORECAST. THE MAIN CONCERN
CONTINUES TO BE THE UPPER LOW THAT WILL SLOWLY DRIFT FROM ITS
CURRENT POSITION JUST NORTH OF MINNESOTA...TO THE NORTHERN GREAT
LAKES FOR MUCH OF THE MID WEEK TIME FRAME. BEYOND THAT...THE
MODEL GUIDANCE CONTINUES TO HAVE TROUBLE AGREEING.

BY TUESDAY MORNING...OUR AREA WILL BE ENCOMPASSED BY WRAP-AROUND
MOISTURE AND CYCLONIC CIRCULATION FROM THE UPPER LOW. DIURNALLY
DRIVEN SHOWERS CONTINUE TO LOOK LIKE A GOOD BET...SO WENT AHEAD
AND INCREASED POPS INTO THE LIKELY CATEGORY FOR TUESDAY AFTERNOON
IN WESTERN WI. IT STILL APPEARS SNOW SHOWERS WILL BE POSSIBLE
EARLY TUESDAY MORNING BEFORE SURFACE TEMPERATURES CAN WARM INTO
THE 40S. IT IS POSSIBLE FOR A DUSTING TO A FEW TENTHS TO
ACCUMULATE ON GRASSY SURFACES...MAINLY ACROSS WEST CENTRAL WI.
MEANWHILE...A SURFACE LOW IN EASTERN ONTARIO WILL DEEPEN AND
APPROACH 990MB...WHILE HIGH PRESSURE PUSHES SOUTH OUT OF MANITOBA.
THIS WILL KEEP THAT STRONG PRESSURE GRADIENT ACROSS THE REGION AND
STRONG NORTHWEST WINDS WILL CONTINUE...BUT EXPECT THEM TO BE JUST
A FEW MPH WEAKER THAN THE WINDS WE`LL SEE TODAY.

SKIES WILL CLEAR FOR MUCH OF SOUTHERN MN BY WEDNESDAY...WHILE WEST
CENTRAL WI REMAINS TRAPPED UNDER MOISTURE ASSOCIATED WITH THE
QUASI-STATIONARY UPPER LOW TO THE EAST. IT WILL BE YET ANOTHER
WINDY DAY ON WEDNESDAY WITH THE SURFACE HIGH PUSHING SLIGHTLY
FURTHER SOUTH AND THE AFOREMENTIONED LOW REMAINING STUBBORNLY IN
PLACE.

FOR THURSDAY AND BEYOND...THE GFS IS STILL INDICATING THE UPPER
LOW WILL STRETCH BACK WEST THROUGH MUCH OF THE PERIOD...WHILE THE
EC CONTINUES TO HOLD FIRM IN SHOVING THE UPPER LOW TO THE EAST
AND AS AN UPPER RIDGE TRIES TO BUILD IN. THE EC HAS SHOWN TO BE
MORE CONSISTENT IN THE DP/DT SO I LEAN A LITTLE MORE TOWARDS ITS
SOLUTION...WHICH WOULD INDICATE DRY WEATHER FOR THE WEEKEND...BUT
HIGH TEMPERATURES STILL LOOK TO BE SLIGHTLY COOLER THAN NORMAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM CDT MON APR 20 2015

LOW STRATUS CONTINUES TO PLAGUE MUCH OF THE AREA THIS MRNG AND
THAT SCENARIO DOES NOT LOOK TO CHANGE THROUGH LATE THIS AFTN...
PARTICULARLY AS AN UPR LVL LOW DRIVES SEWD ACRS THE DAKOTAS AND MN
ON INTO THE CENTRAL GRT LKS BY TMRW MRNG. -SHRA WILL END IN WRN WI
THIS MRNG...THEN ADDITIONAL ISOLD/SCTD -RA WILL DEVELOP THIS AFTN
AND EVE FOR MAINLY ALONG AND N OF I-94. THIS WOULD INCLUDE THE
MAJORITY OF THE TAF SITES...BUT NOT LOOKING FOR ANY VSBY
RESTRICTION. GOING INTO TNGT...THE WI TAF SITES MAY BE SUSCEPTIBLE
TO MORE PERSISTENT PRECIP OVERNIGHT INTO TMRW MRNG...WITH A
MIXTURE OF -RA/-SN. WINDS WILL BE STRONG OUT OF THE NW...WITH
SPEEDS AROUND 20G30KT FROM LATE THIS MRNG THRU MUCH OF THE AFTN
BEFORE DIMINISHING SLIGHTLY OVERNIGHT.

KMSP...CEILINGS MAY APPROACH 2K FT BUT AM NOT LOOKING FOR CEILINGS
TO DROP BELOW THAT...SO MVFR CEILINGS ARE A SOLID BET THRU THE DAY
TDA. A FEW OCNL RAIN SHWRS ARE POSSIBLE TDA ALONG WITH THE LOW
CEILINGS...THEN IMPROVEMENT TO VFR THIS EVENING LOOKS LIKELY.
CEILINGS TO DROP BACK TO MVFR OVERNIGHT WITH THE PASSAGE OF THE
UPPER LOW BUT...ALTHOUGH CANNOT RULE IT OUT COMPLETELY...CHCS FOR
PRECIP ARE TOO LOW ATTM FOR INCLUSION IN THE LATTER PORTION OF THE
TAF.

/OUTLOOK FOR KMSP/
TUE...VFR. WINDS NW AT 20G30KTS.
WED...VFR. WINDS NW AT 15G25KTS.
THU...VFR. WINDS NW 10-15KT.

&&

.FIRE WEATHER...
ISSUED AT 318 AM CDT MON APR 20 2015

WITH TEMPERATURES REMAINING QUITE COOL TODAY...RH VALUES WILL
STRUGGLE TO DIP BELOW 40 PERCENT. VERY STRONG NORTHWEST WINDS ARE
STILL EXPECTED...WITH GENERALLY 20-30 MPH SUSTAINED WINDS WITH
GUSTS OF 35-45 MPH. SHOWERS ARE POSSIBLE ACROSS THE AREA THIS
AFTERNOON. THE MORE CONCERNING DAY LOOKS TO BE TOMORROW...AS
WESTERN MN WILL DRY OUT FURTHER AND HEAT UP MORE THAN TODAY. WIND
SPEEDS WILL BE SLIGHTLY LESS THAN TODAY...BUT NOT BY MUCH SO IT
WILL STILL BE BREEZY. RH VALUES COULD APPROACH 30 PERCENT IN
WESTERN MN...BUT EVEN LOWER IF MORE ABUNDANT SUNSHINE BREAKS OUT
AND HEATS THE SURFACE MORE THAN CURRENTLY EXPECTED.
STILL...TEMPERATURES WILL BE COOL...WITH HIGHS IN THE UPPER 40S
AND LOW 50S EXPECTED IN WESTERN MN TOMORROW...AND GENERALLY MID
40S FURTHER EAST.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING
     FOR MNZ041>043-047>051-054>070-073>077-082>085-091>093.

WI...NONE.
&&

$$

UPDATE...JPC
SHORT TERM...JPC
LONG TERM...SPD
AVIATION...JPC
FIRE WEATHER...SPD



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