Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 260521 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1221 AM CDT SAT JUL 26 2014

.UPDATE...
ISSUED AT 1221 AM CDT SAT JUL 26 2014

UPDATED FOR NEW 06Z AVIATION FORECAST DISCUSSION.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 252 PM CDT FRI JUL 25 2014

A RIDGE OF HIGH PRESSURE COVERED THE FA AT 19Z WHILE A COLD FRONT
WAS SLOWLY MOVING INTO FAR WESTERN MN. AHEAD OF THIS FRONT...AN
UNSTABLE AIRMASS COVERS NE MN WITH PLENTY OF CLOUD COVER THANKS TO
WAA AND ISENTROPIC LIFT. A COUPLE OF ISOLD LIGHTNING STRIKES HAVE
BEEN NOTED NEAR CKC/GNA EARLIER AND JUST RECENTLY NEAR THE BAYFIELD
PENINSULA. OTHERWISE...CLOUD COVER HAS LIMITED CONVECTIVE INITIATION
THIS AFTERNOON. WILL STAGGER POPS FOR THE REST OF THE AFTERNOON TO
ACCOUNT FOR ANY CELLS THAT MAY POP.

THE COLD FRONT IS FORECAST TO REACH THE MN/WI BORDER BY 06Z
SATURDAY. LOW LEVEL CONVERGENCE ALONG THE FRONT AND WEAK UPPER LEVEL
SUPPORT FROM EMBEDDED SHORT WAVE ENERGY WARRANTS KEEP SOME POPS OVER
THE NORTHERN AND EASTERN PORTIONS OF THE FA THIS EVENING. AS THE
FRONT TRAVERSES THE REST OF THE FA OVERNIGHT...HAVE SOME POPS OVER
THE ARROWHEAD AND EASTERN WI FA THROUGH 08Z AND DRY THEREAFTER.

SATURDAY MORNING WILL BE RAIN FREE AS WEAK SFC/UPPER LEVEL RIDGING
COVER THE FA. SATURDAY AFTERNOON IS A BIT TRICKY AS MODELS ARE
DIVERGING IN THEIR QPF SOLUTIONS. THEY DO AGREE THAT A CLOSED UPPER
LOW WILL DROP INTO THE MN/ND/CANADA BORDER AREA BY 00Z SUNDAY. ITS
ASSOCIATED SFC REFLECTION IS SOMEWHAT AMBIGUOUS AND WILL BE
SOMEWHERE NEAR THE MN/CANADA BORDER BY 00Z SUNDAY. ECMWF/GEM ARE
FURTHEST S WITH THEIR QPF INTO NW WI...WHILE THE GFS IS MAINLY
DRY...EXCEPT FOR A FINGER OF QPF INTO THE ST. CROIX VALLEY. TRIED A
MODEL BLEND FROM 18Z SATURDAY TO 00Z SUNDAY FOR POPS TO ACCOUNT FOR
THESE DIFFERENCES. INSTABILITY IS WEAK...BUT ENOUGH IS AVAILABLE FOR
A MENTION OF THUNDER.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 252 PM CDT FRI JUL 25 2014

SATURDAY NIGHT THROUGH THURSDAY...

A FAST MOVING AND DYNAMIC UPPER S/W WILL TRACK FROM SRN MANITOBA
INTO THE WRN GREAT LAKES AREA SAT NIGHT INTO EARLY SUN AFTERNOON. AN
ASSOCIATED INVERTED SFC TROUGH WILL COMBINE WITH THE LARGE SCALE
LIFT FROM THIS WAVE AND SUFFICIENT AVAILABLE MOISTURE TO PRODUCE
SCATTERED RAIN SHOWERS AND THUNDERSTORMS DURING THIS TIME. WEAK
INSTABILITY AND DEEP LAYER SHEAR WILL CONTRIBUTE TO THE DEVELOPMENT
OF CONVECTIVE SHOWERS AND STORMS SAT EVENING AND AGAIN LATE SUN
MORNING AND AFTERNOON. THE GREATEST DEEP LAYER SHEAR WILL QUICKLY
BE SHUNTED TO THE SOUTH ON SUNDAY AND LIMIT THE STRENGTH OF THE
CONVECTION LATE IN THE WEEKEND. THERE COULD BE RAINFALL AMOUNTS
AROUND A HALF INCH OR SO THROUGH THE ARROWHEAD BY SUN AFTERNOON. THE
LARGE SCALE PATTERN THAT TAKES SHAPE THROUGH MOST OF THE WORK WEEK
WILL BE DOMINATED BY A COLD CORE UPPER LOW OVER JAMES BAY AND WRN
QUEBEC. A PERSISTENT NLY FLOW ON THE BACK SIDE OF THE THIS SYSTEM
WILL BE IN PLACE THROUGH THE WEEK WITH A HIGH AMPLITUDE UPPER RIDGE
TO THE WEST HELPING TO USHER IN A WARMER AIR MASS OVER THE CENTRAL
SECTIONS OF THE CONUS. A SERIES OF EMBEDDED WEAK WAVES WILL MOVE SWD
ALONG THE WRN EDGE OF THE LARGE UPPER LOW INTO THE GREAT LAKES
THROUGH THE WEEK. HOWEVER...THE MAIN IMPACTS FROM THIS WILL LIKELY
BE JUST LOW CHANCES FOR AFTERNOON/EVENING CONVECTION. NO SIGNIFICANT
RAINFALL IS EXPECTED THROUGH THE WEEK.

COOL TEMPERATURES SUNDAY WITH HIGHS IN THE 60S AND LOWER 70S WILL BE
REPLACED BY A GRADUAL WARMING TREND THROUGH THE WEEK. EXPECTED HIGHS
TO SLOWLY RISE INTO THE 70S AND LOWER 80S BY WED/THUR. OVERNIGHT
LOWS WILL REMAIN STEADY INTO THE 50S AND LOWER 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1221 AM CDT SAT JUL 26 2014

A FEW ISOLATED SHOWERS AND STORMS WILL CONTINUE TO LINGER FOR A TIME
OVERNIGHT...BUT THE TREND WILL BE FOR A DECREASE AS THE NIGHT WEARS
ON. THE MAIN CHANCE WOULD BE AREAS AROUND KINL...BUT MAINLY AREAS
JUST EAST OF KINL. SHOWERS AND THUNDERSTORMS WILL MOVE BACK INTO THE
PICTURE SATURDAY AFTERNOON AND INCREASE IN COVERAGE INTO THE EVENING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  60  67  53  73 /  50  70  10  10
INL  54  71  49  73 /  50  50  10  10
BRD  60  73  53  75 /  30  50  10   0
HYR  59  69  49  73 /  50  70  10   0
ASX  57  65  50  72 /  60  60  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&

$$

UPDATE...DAP
SHORT TERM...GSF
LONG TERM...BJT
AVIATION...GROCHOCINSKI






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