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000
FXUS63 KMPX 221737
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1237 PM CDT WED MAY 22 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 1219 PM CDT WED MAY 22 2013

WE ARE FINALLY SEEING SOME PROGRESSION... ALBEIT GRUDGINGLY
SLOW... IN THE UPPER LEVEL PATTERN OVER THE CONUS. THE UPPER LOW
WHICH HAS BEEN OVER OUR AREA FOR MANY MANY DAYS IS SLIDING EAST OF
THE REGION... GIVING WAS TO RIDGING WHICH WILL BRING FAIR SKIES
AND DRY WEATHER FOR AT LEAST A COUPLE OF DAYS. THE MODEL GUIDANCE
IS IN GOOD AGREEMENT ON THE ARRIVAL OF THE DRY AIR AND SEASONABLY
COOL TEMPERATURE FOR THE NEXT TWO DAYS... BUT CONTINUES TO SHOW
SOME VARIATION IN HOW THINGS WILL UNFOLD AFTER THAT. BUT... UNTIL
THEN THE OVERALL THEME WILL BE FOR THE DIURNALLY ENHANCED PCPN
CURRENTLY OVER THE AREA TO SHIFT SOUTHEAST OF THE AREA TONIGHT...
ALLOWING FOR SUBSIDENCE AND MUCH DRIER CONDITIONS TO MOVE IN FROM
THE NORTHWEST AS THE SURFACE HIGH OVER CENTRAL CANADA BUILDS INTO
THE REGION. THE UPSTREAM DEWPOINT DEPRESSIONS SUGGEST WE SHOULDN/T
HAVE TOO MUCH OF AN ISSUE WITH DEVELOPMENT OF FOG/STRATUS TONIGHT
ONCE THE CLOUD COVER IS SCOURED OUT... BUT THERE IS AT LEAST SOME
DEGREE OF CONCERN GIVEN HOW MUCH RAINFALL THE AREA HAS SEEN
LATELY. AT THIS POINT... IT LOOKS LIKE WE SHOULD HOLD ONTO ENOUGH
OF A GRADIENT AND SOME WINDS TO KEEP FOG LIMITED TO PATCHES IN LOW
LYING AREAS NEAR BODIES OF WATER... BUT WILL BE SOMETHING TO KEEP
AN EYE ON OVERNIGHT. THURSDAY SHOULD BRING MOSTLY SUNNY SKIES AND
DRY WEATHER TO THE AREA... WITH WARMER READINGS THAN TODAY DUE TO
THE SUNSHINE... ALTHOUGH THEY WILL STILL BE BELOW NORMAL.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 410 AM CDT WED MAY 22 2013

THE PERIOD BEGINS WITH OUR PESKY LOW PRESSURE SYSTEM FINALLY TO
OUR SOUTHEAST ALONG WITH A SUBSTANTIAL CANADIAN HIGH PRESSURE
SYSTEM BUILDING SOUTH ACROSS THE UPPER MISSISSIPPI VALLEY REGION.
THURSDAY AND MUCH OF FRIDAY WILL BE FINE WEATHER DAYS FOR THE FA.
THE MAIN CONCERNS DURING THIS PERIOD CENTER AROUND VERY LOW
DEW POINTS THURSDAY AFTERNOON LEADING TO MIN RH VALUES NEAR 20
PERCENT IN OUR WI CWA AS WELL AS THE THREAT FOR SOME FROST/FREEZE
CONDITIONS...AGAIN MAINLY IN OUR WI COUNTIES THURSDAY NIGHT/FRIDAY
MORNING. USED THE MIX DOWN TD TOOL AS A START FOR THURSDAY
AFTERNOON ALONG WITH SOME CONSRAW/CONSMOS. THIS BROUGHT DEW POINTS
WELL DOWN INTO THE 20S OVER THE AFOREMENTIONED AREA. THE HIGH
PRESSURE SYSTEM WILL BE NEARLY OVERHEAD THURSDAY NIGHT. WITH LIGHT
WINDS...A CLEAR SKY AND DRY AIR IN PLACE...LOWS NEAR FREEZING
INDICATED AROUND LADYSMITH WITH MIDDLE 30S AS FAR WEST AS THE
MN/WI BORDER AND WELL AS TO THE NORTH OF THE TWIN CITIES.
INDICATED FROST IN VARYING DEGREES OF COVERAGE STARTING WITH LOWS
36 DEGREES OR COLDER.

BEGINNING WITH FRIDAY IS WHERE THINGS START TO SLOWLY UNWIND WITH
MODEL CONSISTENCY. THE NAM AT THIS POINT IS THE FASTEST ON FRIDAY
ON BRINGING BACK SHOWERS AND SOME THUNDERSTORMS ACROSS MUCH OF THE
MN CWA ON FRIDAY AS MOISTURE AND INSTABILITY BEGIN TO INCREASE ON
THE BACKSIDE OF THE HIGH. THE GEM/GFS AND EURO WOULD KEEP ALL BUT
THE FAR WEST DRY. THEREFORE...REMOVED THE MENTION OF POPS IN THE
12Z-18Z TIME FRAME AND KEPT THE 18Z-24Z POPS CONFINED TO THE FAR
WEST. THE GEM/GFS/EURO THEN INDICATED SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF THE FA FRIDAY NIGHT AND SATURDAY.
PROBABILITIES FOR MEASURABLE PRECIPITATION ARE LEAST IN THE FAR
EASTERN WI COUNTIES. NOTHING TOO SIGNIFICANT (RAINFALL/SEVERE
WEATHER) EXPECTED AT THIS TIME AS SMALL RIPPLES IN THE UPPER FLOW
MIGRATE NORTHEAST OUT OF A LARGE UPPER TROUGH IN THE WESTERN
UNITED STATES.

PROGRESSING DEEPER INTO THE HOLIDAY WEEKEND SHOWS TWO CAMPS
THROUGH MEMORIAL DAY. THE GFS IS WET ACROSS US SUNDAY AND MONDAY
WHILE THE EURO IS BASICALLY DRY. THE DIFFERENCE IS SEEN IN THE
UPPER PATTERN. THE PESKY UPPER LOW THAT HAS TORMENTED US FOR THE
PAST FIVE DAYS REACHES THE EASTERN SEABOARD BY FRIDAY AND DEEPENS
AS MORE ENERGY DROPS INTO IT FROM THE NORTH. THE EURO IS DEEPEST
AND SLOWEST WITH THIS FEATURE WHICH ACTUALLY BUILDS THE SURFACE
HIGH BACK WEST FOR A TIME LATE IN THE WEEKEND. THE GEM DOES NOT
HAVE AN UPPER LOW AND ALLOWS FOR MORE PROGRESSION OF THE UPPER
PATTERN AND PLENTY OF RAINFALL. HENCE...CHANCES POPS INDICATES FOR
MANY PERIODS OF THE EXTENDED FORECAST DUE TO THE BLENDED GUIDANCE.

THE CIPS ANALOGS WERE LOOKED AT OVERNIGHT TO SEE WHAT SORT OF SEVERE
WEATHER OCCURRED WITH OUR PATTERN AHEAD. USING THE 144 HOUR
ANALOG GUIDANCE SHOWED ALL FORMS OF SEVERE WEATHER WITH THE MOST
CLUSTERING OVER SD/NE/KS/IA WITH SOME SEVERE WEATHER REPORTS OVER
FAR WESTERN AND FAR SOUTHERN MN. THIS CORRELATES WELL WITH THE GFS
HAVING LOW PRESSURE FORMING DURING THIS PERIOD OVER THE CENTRAL
PLAINS WITH A WARM FRONT MEANDERING TO THE LOWER OHIO VALLEY. THE
EURO WOULD BE A LITTLE SLOWER. SO WE MAY DODGE SEVERE WEATHER
DURING THE WEEKEND...BUT THE THREAT WILL BE ON THE INCREASE BY THE
MIDDLE OF NEXT WEEK AS THE LOW PRESSURE SYSTEM AND WARM FRONT
ADVANCE INTO THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY
REGION.

HIGH/LOW TEMPERATURES WILL BE MAINLY BELOW NORMAL THROUGH THE
WEEKEND WITH A CLIMB BACK ABOVE FOR EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1219 PM CDT WED MAY 22 2013

THE MAIN THEME FOR THE FORECAST WILL BE IMPROVING CONDITIONS FOR A
CHANGE AS THE RIDGE TO OUR NORTHWEST FINALLY WORKS INTO THE
REGION. UNTIL THAT OCCURS... HOWEVER... WE WILL CONTINUE TO DEAL
WITH MVFR AND LOCAL IFR CEILINGS THIS AFTERNOON INTO THIS
EVENING... WITH VISIBILITIES ALSO DROPPING INTO MVFR WITH RAIN AT
TIMES. CONFIDENCE IN THE OVERALL TREND OF THE FORECAST IS FAIRLY
HIGH... BUT THERE COULD STILL BE SOME SLIGHT DIFFERENCES IN TIMING
OF THINGS AND CEILINGS/VISIBILITIES COULD VARY A BIT MORE THAN
FORECAST. HOWEVER... DO NOT ANTICIPATE AS MUCH VARIABILITY OR NEED
FOR AMENDMENTS AS THE PAST FEW DAYS.

KMSP...TAF REFLECTS EXPECTED TRENDS WITH A REASONABLE DEGREE OF
CONFIDENCE OVERALL. CEILINGS THIS AFTERNOON COULD IMPROVE A BIT
QUICKER THAN SUGGESTED... BUT IT IS ALSO POSSIBLE THAT THEY WILL
STAY DOWN NEAR 1000 FT AGL THROUGH THE AFTERNOON. VISIBILITIES
SHOULD BE VFR EXCEPT WITH PATCHES OF RAIN WHEN THEY COULD DROP AS
LOW AS 3-4SM FOR A BRIEF TIME. WINDS WILL BE CONSISTENT FROM THE
N/NNE THROUGH THE PERIOD. TIMING OF THE BIG IMPROVMENT TO VFR
TONIGHT MAY DIFFER BY +/- 2 HOURS OR SO FROM FORECAST.

/OUTLOOK FOR KMSP/
THURSDAY NIGHT...VFR CONDITIONS EXPECTED. EAST WIND LESS THAN 10
KT BECOMING SOUTHEAST.
FRIDAY AND FRIDAY NIGHT...VFR CONDITIONS EXPECTED. SOUTHEAST WIND
5 TO 15 KT.
SATURDAY...BRIEF MVFR CEILINGS POSSIBLE WITH A CHANCE OF
SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT.
SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A
CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT.
SUNDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF
SHRA/TSRA... BRIEF IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 10 TO
20 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...
LONG TERM...RAH
AVIATION...