Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 230522 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1222 AM CDT WED APR 23 2014

.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 325 PM CDT TUE APR 22 2014

HIGH PRESSURE OVER THE NORTHLAND WILL BEGIN TO SHIFT TO THE EAST
TONIGHT. CLEAR SKIES AND LIGHT WINDS ARE EXPECTED FOR AT LEAST
TONIGHT, AND FOR ALL OF THE NIGHT ACROSS THE EASTERN FORECAST
AREA. AS FOR THE WESTERN FORECAST AREA, THERE WILL BE INCREASING
HIGH CLOUDS FROM THE WEST AS A LOW PRESSURE SYSTEM DEVELOPS IN THE
NORTHERN HIGH PLAINS. THE CLEAR SKIES AND LIGHT WINDS WILL PROMOTE
RADIATIONAL COOLING. LOW TEMPERATURES SHOULD RANGE FROM THE MID TO
UPPER 20S IN THE EASTERN FORECAST AREA TO THE LOW TO MID 30S
ACROSS THE WESTERN FORECAST AREA. THERE IS THE POSSIBILITY OF FOG
TONIGHT...HOWEVER I AM NOT CONFIDENT AT THIS POINT. THE LOCAL
WRF...NAM...AND RAP MODELS ARE SUGGESTING IT IS POSSIBLE ACROSS
THE EASTERN FORECAST AREA...ESPECIALLY CLOSER TO LAKE SUPERIOR.
THIS IS SOMETHING THE EVENING SHIFT CAN LOOK MORE INTO WHEN MORE
HIGH RESOLUTION MODEL DATA IS AVAILABLE.

WEDNESDAY...A DEEP MID/UPPER LEVEL LOW WILL MOVE EAST FROM THE
PACIFIC NW TO NORTHERN MONTANA. SURFACE LOW PRESSURE WILL CONTINUE
TO DEVELOP AND ORGANIZE IN THE PLAINS...AND BEGIN TO BRING
INCREASING SE FLOW AND MOISTURE TO THE UPPER MIDWEST. THE LOW
LEVEL SE FLOW WILL BEGIN FAIRLY DRY...SO IT WILL LIKELY TAKE SOME
TIME FOR THE LOW LEVELS TO SATURATE BEFORE THE NORTHLAND SEES ANY
SIGNIFICANT RAINFALL. THE GFS IS FASTER THAN OTHER MODELS AT
BRINGING IN THE PCPN INTO THE FORECAST AREA...SO I LEANED MORE ON
THE SREF/NAM/GEM/ECMWF. THE INCREASING CLOUD COVER WILL RESULT IN
COOLER TEMPERATURES FOR MUCH OF THE NORTHLAND COMPARED TO TODAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE APR 22 2014

THE BIG CONCERN FOR THE LONG TERM IS THE MAJOR STORM SYSTEM THAT
IS EXPECTED TO MOVE THROUGH THE REGION LATE IN THE WEEK. THERE
ARE SOME DISTINCT MODEL DIFFERENCES DURING THIS TIME PERIOD...AS
THE MODELS ATTEMPT TO PHASE TWO LOW PRESSURE SYSTEMS INTO ONE MAIN
LOW OVER THE WESTERN GREAT LAKES. THE UK/EC AND EVEN THE NAM
GENERALLY MAINTAIN TWO DISCRETE LOW AREAS...WITH THE GFS AND GEM
COMPLETELY PHASING THE DUAL LOW ENERGY INTO ONE LOW. THE IMPACT ON
SENSIBLE WEATHER IS NOT SO DRAMATIC...AS ALL OF THE MODELS SUPPORT
FAIRLY HIGH TOTAL QPF. BUT THERE ARE DIFFERENCES IN THE THERMAL
PROFILES AND OF COURSE IN WINDS. OVERALL...WILL BE A LITTLE
CAREFUL ABOUT COMPLETELY PHASING THE TWO SURFACE LOWS...AND
FAVORING A SOLUTION A BIT MORE IN LINE WITH THE ECMWF. OF PERHAPS
THE MOST CONCERN FOR OUR AREA IS THE CHANCE OF ACCUMULATING
SNOWFALL. MODEL RUN SNOW ACCUMULATION VALUES ARE FAIRLY HIGH FOR
NORTHEASTERN MN...ESPECIALLY OVER THE TIP OF THE ARROWHEAD...WHERE
ALL OF THE MODELS BASICALLY SUPPORT THE POTENTIAL FOR MORE THAN 6
INCHES OF SNOW. AFTER COORDINATING WITH HPC AND THE WINTER WEATHER
DESK...THINK THERE IS TIME TO HOLD OFF ON ISSUING A WATCH FOR THE
ARROWHEAD DUE TO DIFFERENCES IN THERMAL PROFILES OF FORECAST
SOUNDINGS...DIFFERENCES IN HOW THE MODELS ARE HANDLING THE PHASING
OF THE TWO LOW STRUCTURE AND QUESTIONS ABOUT THE POTENTIAL FOR
SIGNIFICANT MELTING. SPRING SYSTEMS LIKE THIS ARE NOTORIOUSLY
DIFFICULT THIS FAR OUT...AS SUBTLE CHANGES IN THE THERMAL PROFILES
COULD YIELD DRAMATICALLY DIFFERENT OUTCOMES. AT THIS POINT...NOT
COMFORTABLE ISSUING A WATCH FOR THE ARROWHEAD...BUT IT IS
SOMETHING WE WILL NEED TO WATCH VERY CLOSELY AND MAY EVENTUALLY
NEED A WATCH. FURTHER SOUTH...SOUTH OF THE IRON RANGE...THERE IS
ALSO THE POTENTIAL FOR SOME SNOW ACCUMULATION...BUT IT SHOULD
GENERALLY BE A SLUSH ACCUMULATION OF MAYBE UP TO A COUPLE INCHES.
EVEN FURTHER SOUTH FROM EAST CENTRAL MINNESOTA INTO OUR SOUTHERN
TIER OF COUNTIES...THERE SHOULD BE LITTLE TO NO SNOW ACCUMULATION.
NO MATTER WHAT...IT WILL BE A WET AND POTENTIALLY SNOWY END TO THE
WEEK FOR THE CWA. IT SHOULD THEN BE QUIET AND MAINLY DRY FOR THE
WEEKEND. WILL ALSO NEED TO WATCH THE SYSTEM FOR LATE IN THE
WEEKEND...AND EARLY NEXT WORK WEEK...BUT FOR NOW IT LOOKS LIKE IT
MAY NOT TOTALLY GET ITS ACT TOGETHER TO HAVE A MAJOR IMPACT ON OUR
WEATHER. THAT MAY CHANGE AS IT IS QUITE A WAYS OUT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1218 AM CDT WED APR 23 2014


EXPECT HIGH CLOUDS TO INCREASE TONIGHT INTO WEDNESDAY MORNING...WITH
CEILINGS LOWERING THROUGH THE REST OF THE PERIOD. AN AREA OF LOW
PRESSURE WILL IMPACT THE REGION AND SPREAD AN AREA OF RAIN FROM
SOUTHWEST TO NORTHEAST THROUGH THE REGION WEDNESDAY INTO WEDNESDAY
NIGHT. AT THIS TIME...WE JUST HAVE RAIN IN THE TAFS...BUT THERE ARE
INDICATIONS NORTHERN TAF SITES COULD SEE A MIX. WE THINK THE MIX
WILL OCCUR MAINLY AFTER 06Z THOUGH. CEILINGS/VSBYS WILL LOWER TO
MVFR OR EVEN IFR LATE IN THE PERIOD.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  34  43  32  43 /  80  90  60  40
INL  36  45  32  42 /  80  90  70  40
BRD  41  52  35  49 /  90  70  40  30
HYR  38  50  35  49 /  90  90  50  40
ASX  36  47  34  44 /  80  90  70  50

&&

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

$$

SHORT TERM...GROCHOCINSKI
LONG TERM...DAP
AVIATION...MELDE/CANNON






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