Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 050109 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
809 PM CDT FRI SEP 4 2015

.UPDATE...
ISSUED AT 809 PM CDT FRI SEP 4 2015

NORTH-SOUTH ORIENTED LINE OF THUNDERSTORMS CONTINUES TO CHURN
ACROSS N-CENTRAL MN THIS EVENING...TAPPING INTO A VERY UNSTABLE
AIR MASS. WITH ROUGHLY 2000-3000 J/KG OF ML CAPE AND PLENTY OF
DEEP LAYER MOISTURE TO WORK WITH...THE STORMS WILL LIKELY CONTINUE
THROUGH THE NIGHT. THERE ARE A FEW LIMITING FACTORS KEEPING THE
THREAT OF THE STORMS MAINLY HEAVY RAIN AND LIGHTNING. THERE IS A
LACK OF DEEP LAYER SHEAR AVAILABLE TO KEEP THE STORMS FROM
ROTATING AND SUSTAINING THEMSELVES. THE STORM ARE SELF-DESTRUCTIVE
FOR THE MOST PART. AS THE LINE SHIFTS TO THE N/NE TONIGHT THE
STORMS WILL MOVE INTO A MORE STABLE AIR MASS AND DIMINISH IN
INTENSITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 319 PM CDT FRI SEP 4 2015

FORECAST FOCUS THROUGH THE SHORT TERM WILL BE ON THUNDERSTORM
CHANCES AND STRENGTH.

AS OF LATE AFTERNOON A FEW SHOWERS HAVE DEVELOPED AND DISSIPATED ACROSS
OUR SOUTHWEST ZONES. THIS WAS OCCURRING NORTH OF THE WARM FRONT IN
AN AREA OF WAA. A STRONGER SHORTWAVE WAS LIFTING NORTH THROUGH
EASTERN NORTH DAKOTA AND WILL MOVE THROUGH NORTHWEST MINNESOTA AS
IT CONTINUES INTO ONTARIO THIS EVENING. PLENTY OF INSTABILITY WAS
PRESENT ACROSS MOST OF THE NORTHLAND WITH MLCAPE OF 1000-1500J/KG
OVER OUR WESTERN ZONES. SHEAR HAS BEEN LACKING...BUT ENHANCEMENT
WILL OCCUR NEAR THE SHORTWAVE THIS AFTERNOON/EVENING AND COULD
LEAD TO A FEW STRONG STORMS. PLENTY OF MOISTURE WAS PRESENT AS
WELL...AND WILL INCREASE OVERNIGHT. THE NAM/GFS BOTH SHOW PWAT
VALUES RISING TO 1.6 TO 1.8 INCHES TONIGHT AND CONTINUING INTO
SATURDAY. THE NAM HAS THE HIGHEST VALUES AND SHOWS AN AREA OF 2
INCH PWAT VALUES OVER MUCH OF OUR MINNESOTA ZONES SATURDAY
AFTERNOON. THIS MORNINGS KINL SOUNDING SHOWED 1 INCH OF PWAT...AND
NORMAL VALUES ARE AROUND 0.70 INCHES.

WE EXPECT SHOWERS AND STORMS TO CONTINUE TO DEVELOP THIS
EVENING...AND BE MOST WIDESPREAD OVER OUR FAR NORTHERN ZONES TONIGHT
WHICH WILL BE BRUSHED BY THE STRONGER LIFT ASSOCIATED WITH THE UPPER
WAVE. A LLJ AND CONTINUED WAA WILL KEEP THE THREAT FOR
SHOWERS/STORMS GOING ELSEWHERE TONIGHT. AS THE UPPER WAVE MOVES INTO
ONTARIO LATE TONIGHT/SATURDAY MORNING...LIFT WILL DIMINISH ACROSS
THE NORTHLAND AND WE LOWERED POPS SATURDAY MORNING INTO EARLY
AFTERNOON AND REMOVED THEM IN SPOTS. BRIEF SHORTWAVE RIDGING WILL
OCCUR BEHIND THE WAVE BUT ANOTHER SHORTWAVE WILL TRACK INTO NORTHERN
MINNESOTA SATURDAY AFTERNOON CAUSING SHOWERS AND STORMS TO INCREASE
IN COVERAGE THROUGH THE AFTERNOON. THERE WILL BE A CHANCE FOR SOME
STRONG TO SEVERE STORMS SATURDAY AFTERNOON AS INSTABILITY IS
EXPECTED TO BE SUPPORTIVE AND SHEAR SHOULD AGAIN INCREASE AS THE
WAVE NEARS. THERE ARE QUESTIONS TO HOW MUCH CLOUD COVER WILL BE
AROUND WHICH COULD LIMIT SURFACE/MLCAPE VALUES. HEAVY RAIN WILL BE A
THREAT WITH SUCH HIGH PWAT VALUES...MAINLY THIS EVENING AND AGAIN
SATURDAY AFTERNOON OVER NORTHERN AREAS.

WE EXPECT HIGHS IN THE 80S FOR MOST AREAS SATURDAY WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. IT WILL BE A VERY WARM AND
MUGGY DAY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 319 PM CDT FRI SEP 4 2015

SATURDAY NIGHT STARTS OFF WET AND STORMY AS A LOW PRESSURE IN THE
DAKOTAS APPROACHES THE NORTHLAND FROM THE WEST. MODEL AGREEMENT
BETWEEN THE GFS/ECMWF/NAM IS ACTUALLY SOMEWHAT IMPRESSIVE WITH
TIMING AND COVERAGE... WITH ALL SOLUTIONS POINTING TOWARDS A
BULLSEYE OF INCH OR MORE OF QPF ACROSS THE NORTHLAND OVERNIGHT
SATURDAY AND INTO SUNDAY MORNING. ANOTHER ROUND OF HEAVY RAIN WILL
COME SUNDAY NIGHT AS A CUTOFF LOW SLIDES INTO THE CANADIAN PRAIRIES
AND THE ASSOCIATED COLD FRONT MOVES ACROSS MINNESOTA OVERNIGHT AND
INTO WISCONSIN MONDAY MORNING. NAMBUFR FCST SOUNDINGS FOR SUNDAY AND
ARE QUITE IMPRESSIVE... WITH 3000+ J/KG OF AMPLE INSTABILITY...
PWATS AROUND 2 INCHES... 35KTS OF BULK SHEAR... A HODOGRAPH
STRETCHING OUT TO 60 KTS AT TIMES... AND STEEP LAPSE RATES. FCAST
STORM MOTION POINTS TOWARDS STORMS TRAINING OVER THE SAME AREA...
AND WITH PWATS IN THE 99 PERCENTILE RANGE FOR THIS TIME OF YEAR...
THERE IS A CONCERN OF NOT ONLY STRONG TO SEVERE THUNDERSTORMS... BUT
ALSO FLASH FLOODING. THERE MAY BE A POSSIBILITY THAT A FLOOD WATCH
MAY BE NEEDED FOR SUNDAY NIGHT AND MONDAY. TUESDAY... A SECOND SHORT
WAVE MOVES THROUGH... GIVING SMALL CHANCES OF RAIN. INSTABILITY WILL
BE GENERALLY LACKING BY THIS TIME... SO MORE IN THE WAY OF SHOWERS
THAN STORMS FOR MOST OF THE CWA. ANOTHER DISTURBANCE MOVES THROUGH
WEDNESDAY NIGHT... BRINGING ANOTHER CHANCE OF SHOWERS.

AS FAR AS TEMPS GO... IT WILL BE A WARM AND MUGGY FOR THE SECOND
PART OF LABOR DAY WEEKEND WITH FLORIDA-LIKE DEWPOINTS IN THE LOW
70S... BUT MINNESOTA-LIKE HIGH TEMPS IN THE LOW 80S WHICH YIELD HEAT
INDEX VALUES APPROACHING 90. A COOL DOWN WILL COME MONDAY AFTER THE
FROPA... AND A SECOND COOL DOWN WEDNESDAY SETTING UP HIGHS FOR THE
REST OF THE WEEK IN MID 60S. AFTER WEDNESDAY... EXPECT LOWS TO DIP
BACK INTO THE MID 40S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 701 PM CDT FRI SEP 4 2015

IMMEDIATE CONCERN IS THE THUNDERSTORMS DEVELOPING JUST TO THE WEST
OF KINL AND KBRD...AT THE MOMENT ALL TERMINALS ARE IN VFR CIGS.
THUNDERSTORM DEVELOPMENT IS DUE TO A SHORTWAVE MOVING THROUGH
EASTERN NORTH DAKOTA. THE SHORTWAVE WILL MOVE INTO WESTERN ONTARIO
AROUND 09Z...AND BEHIND IT SOME RIDGING WILL OCCUR. THIS WILL
RESULT IN A LULL IN PRECIPITATION EARLY SATURDAY MORNING...BUT
ANOTHER SHORTWAVE WILL MOVE IN FROM THE EASTERN DAKOTAS SATURDAY
AFTERNOON AND EVENING BRINGING MORE SHOWERS AND THUNDERSTORMS.

IF AN INDIVIDUAL THUNDERSTORM MOVES THROUGH A TERMINAL...MVFR OR
LOWER CONDITIONS CAN BE EXPECTED. WILL NEED TO KEEP A CLOSE EYE ON
THINGS AS STORMS DEVELOP. KEPT VFR CIGS AND VISBY AT ALL
TERMINALS UNTIL 06Z TO 08Z. DURING THIS TIME EXPECTING FOG TO
DEVELOP AT ALL TERMINALS. BROUGHT ALL SITES TO MVFR VISBY...BUT
MOS GUIDANCE AND GFSLAMP SUGGEST THAT ALL TERMINALS EXCEPT FOR
KINL WILL SEE IFR CIG/VISBY BETWEEN 09Z AND 12Z. UNCERTAIN ON HOW
WIDESPREAD IFR WILL BE DURING THIS TIME...SO KEPT IN AS A TEMPO
GROUP FOR THE TIME BEING.

VFR CONDITIONS WILL REDEVELOP AT ALL TERMINALS BETWEEN 14Z AND
19Z. SHOWERS AND STORMS WILL ONCE AGAIN BE A THREAT DURING THE
AFTERNOON AND EVENING...BUT WILL BE MORE WIDESPREAD. UNCERTAIN AT
THIS POINT IN TIME ON HOW WIDESPREAD THUNDERSTORM ACTIVITY WILL BE
SO LEFT IN AS VCSH.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  61  82  67  82 /  40  30  70  60
INL  66  82  66  82 /  70  60  80  60
BRD  70  85  71  83 /  40  50  80  50
HYR  67  85  71  83 /  30  30  30  60
ASX  62  86  69  85 /  20  20  30  50

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LSZ144-145.

&&

$$

UPDATE...TENTINGER
SHORT TERM...MELDE
LONG TERM...MCLOVIN
AVIATION...WL



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