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000
FXUS63 KDLH 060013
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
613 PM CST WED MAR 5 2014

.UPDATE...
ISSUED AT 611 PM CST WED MAR 5 2014

UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.

&&

.SYNOPSIS...
ISSUED AT 348 PM CST WED MAR 5 2014

SURFACE RIDGE OVER EASTERN ONTARIO WITH A RIDGE AXIS EXTENDING
SOUTHWEST ACROSS THE FORECAST AREA THIS MORNING HAS PRODUCED
GENERALLY QUIET WEATHER.  THE LIGHT EAST FLOW HAS PRODUCED A
STRONGER NORTHEAST FLOW OVER LAKE SUPERIOR...AND THE CONVERGENCE
ALONG THE NORTH SHORE PRODUCED SOME LAKE ENHANCED CUMULUS AND A FEW
SNOW SHOWERS THIS MORNING AND EARLY AFTERNOON. A WARM FRONT
EXTENDING FROM CENTRAL MONTANA EAST-SOUTHEAST ACROSS THE HIGH PLAINS
WILL BE APPROACHING THE AREA...WITH PRESSURE FALLS ACROSS NORTH
DAKOTA.  THE STRONG WARM AIR ADVECTION OVER THE WARM FRONT AND
SHORTWAVE HAS PRODUCED A BROAD AREA OF LIGHT SNOW OVER SOUTHERN
MANITOBA AND ONTARIO...WHICH HAS BEEN MOVING GRADUALLY EAST DURING
THE DAY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 348 PM CST WED MAR 5 2014

TONIGHT THE WARM FRONT AND SHORTWAVE WILL MOVE ACROSS SOUTHERN
ONTARIO...BRINGING SNOW CHANCES TO THE NORTHERN PORTIONS OF THE
FORECAST AREA OVERNIGHT TONIGHT.  ANOTHER SHORTWAVE ON A TRACK
SLIGHTLY FARTHER SOUTH ALONG WITH CONTINUED WARM AIR ADVECTION WILL
BRING MORE SNOW TO THE NORTHERN PORTIONS OF THE FORECAST AREA
THURSDAY.  THE MAIN QUESTION FOR BOTH IS HOW FAR SOUTH THE SNOW WILL
EXTEND.  ALSO...WITH THE STRONG WARM AIR ADVECTION AND MELTING GOING
ON TO OUR SOUTH...WE MAY HAVE STRATUS AND DRIZZLE WITH THIS EVENT AS
WELL.  FOR NOW...HAVE KEPT LIKELY OR HIGHER POPS ALONG THE NORTHERN
BORDER...WITH CHANCES DOWN TO AROUND HIGHWAY 2 BOTH PERIODS.
FREEZING DRIZZLE POTENTIAL IS GOING TO DEPEND UPON HOW MUCH LOW
LEVEL MOISTURE WE CAN GET ADVECTED IN HERE...AND IS LIKELY TO BE
ALONG THE SOUTHERN FRINGES OF THE SNOWFALL.  REFINEMENTS WILL HAVE
TO BE MADE AS WE GET CLOSER IN AND WE SEE HOW THINGS DEVELOP.

TEMPERATURES TONIGHT WILL REMAIN MILD WITH CLOUD COVER AND WARM AIR
ADVECTION GOING ON TO KEEP TEMPERATURES UP.  WHERE CLOUDS REMAIN
CLEAREST LONGEST ACROSS THE EAST...TEMPERATURES SHOULD STILL FALL TO
AROUND ZERO.  HOWEVER...FARTHER WEST WHERE WE ARE ALREADY
CLOUDY...TEMPERATURES SHOULD ONLY FALL TO AROUND 10 ABOVE...WHICH
HAS GOTTEN INTO THE MID 20S TODAY.   THURSDAY WILL FEEL DOWNRIGHT
BALMY WITH THE STRONG WARM AIR ADVECTION PUSHING TEMPERATURES UP
INTO THE UPPER 20S TO AROUND FREEZING.  HAVE GONE ON THE WARM SIDE
OF GUIDANCE WITH THE STRONG SOLAR INSOLATION...BUT CLOUD COVER MAY
KEEP THESE VALUES DOWN.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 PM CST WED MAR 5 2014

A LOW PRESSURE SYSTEM...WHICH WILL BE IN THE DAKOTAS THURSDAY...WILL
MOVE EAST ACROSS ONTARIO AND NORTHERN MINNESOTA THURSDAY NIGHT. THE
SYSTEM WILL THEN BRING A COLD FRONT THROUGH THE NORTHLAND FRIDAY AS
IT CONTINUES ITS EASTWARD PROGRESSION. THIS SYSTEM WILL LIKELY
PRODUCE LIGHT SNOW...ABOUT 1 TO 2 INCHES...ACROSS THE NORTHERN
FORECAST AREA THURSDAY NIGHT...AND POSSIBLY A MIX OF SNOW/FZDZ/SLEET
ACROSS THE SOUTHERN FORECAST AREA. THE MODEL SOUNDINGS ARE NOT CLEAR
ON THE PCPN TYPE ACROSS THE SOUTHERN FORECAST AREA. SOME INDICATE
SOUNDINGS INDICATE PERIODS WITH PLENTY OF ICE NUCLEATION
ALOFT...AND OTHERS NOT. SOME SOUNDINGS INDICATE A 2 TO 3 DEGREE
MELTING LAYER AROUND 850 HPA...WHILE OTHERS ARE CLOSER TO 0 DEGREES.
CONSIDERING ALL THESE DIFFERENCES...I DECIDED TO JUST KEEP THE
SOUTHERN FORECAST AREA A WINTRY MIXTURE OF PCPN. WE WILL HOPEFULLY
NARROW DOWN THE DETAILS TONIGHT OR THURSDAY.

VERY LIGHT SNOW COULD LINGER FRIDAY. THE NORTHLAND CAN EXPECT A
COUPLE COOLER DAYS...FRIDAY AND SATURDAY...AS HIGH PRESSURE MOVES
INTO THE REGION.

A MORE SIGNIFICANT WARM UP IS LIKELY LATE THIS WEEKEND AND EARLY
NEXT WEEK. TEMPERATURES WILL LIKELY CLIMB TO ABOVE NORMAL FOR A
CHANGE. A CLIPPER WILL MOVE NORTH AND EAST OF THE FORECAST AREA
SUNDAY...AND IT COULD BRING VERY LIGHT SNOW TO THE FORECAST AREA FOR
LATE THIS WEEKEND AND EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 611 PM CST WED MAR 5 2014

THE FORECAST OVER THE DURATION OF THE TAF PERIOD IS A BIT COMPLEX.
THE MODELS ARE HINTING AT THE DEVELOPMENT OF LOW CLOUDS AND PATCHY
FREEZING DRIZZLE OVERNIGHT. HAVE CONTINUED THE MENTION OF MVFR TO
IFR CIGS/VSBYS DUE TO FOG AND FZDZ/SN. COULD BE SOME IMPROVEMENT
THROUGH THE DAY ON THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH   3  29  22  30 /  10  20  50  10
INL  13  31  18  24 /  70  70  60  20
BRD  13  34  24  28 /  10  10  30  10
HYR   0  32  24  35 /   0  10  40  20
ASX   1  33  24  34 /  10  10  50  30

&&

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

$$

UPDATE...DAP
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...GROCHOCINSKI
AVIATION...DAP