Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 260009
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
709 PM CDT FRI JUL 25 2014

.UPDATE...
ISSUED AT 706 PM CDT FRI JUL 25 2014

UPDATED FOR NEW 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 706 PM CDT FRI JUL 25 2014

WIDESPREAD CLOUD COVER WILL PERSIST FOR THE REMAINDER OF THE
NIGHT. WE ARE NOT SEEING MUCH ON OUR RADAR AT THIS TIME BUT WE DO
EXPECT SCATTERED SHOWERS AND STORMS TO DEVELOP. THIS WILL RESULT
IN SOME HIGHLY VARIABLE CIGS BETWEEN VFR AND MVFR/IFR. CONDITIONS
WILL IMPROVE ON SATURDAY AS DRIER AIR MOVES IN AHEAD OF THE NEXT
FRONTAL BOUNDARY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  61  83  60  67 /  10  30  50  70
INL  58  82  54  71 /  20  60  50  50
BRD  58  85  60  73 /   0  20  30  50
HYR  64  83  59  69 /  20  10  50  70
ASX  63  83  57  65 /  20  20  60  60

&&

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

$$

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





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