227
FXUS63 KMPX 142334
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
634 PM CDT WED APR 14 2021
UPDATE
FOR 00Z AVIATION DISCUSSION BELOW
SHORT TERM
(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 311 PM CDT WED APR 14 2021
THE UPPER LOW THIS AFTERNOON IS CENTERED OVER THE STRAIGHTS OF
MACKINAC. HOWEVER, ITS CYCLONIC FLOW EXTENDS BACK TO EASTERN MN,
WITH ONE MORE LOBE OVER ENERGY SWINGING DOWN FROM THE DULUTH AREA
THAT'S GIVING US ONE LAST ROUND OF SCATTERED SHOWERS (OF THE RAIN
VARIETY THIS TIME!) THAT WILL PERSIST INTO THE EARLY EVENING FOR
EASTERN MN AND WESTERN WI. TONIGHT, THE CYCLONIC FLOW PUSHES OFF TO
THE EAST AND FOR THE REST OF THE SHORT TERM PERIOD, WE'LL BE STUCK
IN A NO-MAN'S LAND BETWEEN AN UPPER LOW OVER THE EASTERN GREAT LAKES
AND ANOTHER OVER THE CENTRAL ROCKIES. THIS PUTS US IN A REGION OF
SUBSIDENCE AND SURFACE HIGH PRESSURE, WHICH MEANS DRY WEATHER FOR
THURSDAY/THURSDAY NIGHT.
FOR TEMPERATURES, DID UNDERCUT NBM FOR HIGHS ON THURSDAY, KEEPING US
STUCK IN THE 40S ONCE AGAIN. IN THIS COOL/CLOUDY AIRMASS, THE NBM
HAS CONSISTENTLY BEEN HIGHS, SO PUSHED HIGHS FOR
TOMORROW CLOSER TO WHAT THE HRRR HAS. WE SHOULD SEE SOME SUNNY SKIES
DEVELOP IN THE AFTERNOON OVER WI, SO IF ANYWHERE IS GOING TO SNEAK
INTO THE 50S ON THURSDAY, THAT IS WHERE IT WILL BE.
LONG TERM
(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 PM CDT WED APR 14 2021
GLOOMY, COOL WEATHER CONTINUES FRIDAY INTO SATURDAY AS WEAK FLOW
ALOFT KEEPS OUR PERSISTENT AIR MASS STATIONARY. HOWEVER, A WEAK
TROUGH IS FORECAST TO PUSH THROUGH SATURDAY NIGHT, BRINGING
NORTHWEST FLOW AFTERWARDS. THIS WILL HELP CLEAR OUT CLOUDS AND MAKE
FOR A SUNNIER SUNDAY. THE WEEKEND'S WEATHER LOOKS SOMEWHAT SIMILAR
AS PREVIOUS FORECASTS WITH DRY CONDITIONS CONTINUING THROUGH SUNDAY.
HOWEVER, WITH PAST FORECASTS UNDERESTIMATING THE COOLNESS OF THE
CURRENT AIR MASS AND LATEST GUIDANCE TRENDING DOWNWARD, HAVE DECIDED
TO SLIGHTLY LOWER HIGH TEMPERATURES FRIDAY THROUGH SATURDAY. LOWS
WILL BE IN THE 30S WHILE HIGHS ARE IN THE UPPER 40S TO LOWER 50S.
SUNDAY'S HIGHS ARE STILL A LITTLE IN QUESTION WITH THE TIMING OF A
COLD FRONTAL PASSAGE SUNDAY NIGHT.
OUR NEXT CHANCE OF PRECIPITATION ARRIVES SUNDAY NIGHT INTO MONDAY
WITH SAID COLD FRONT. A TROUGH WITHIN THE NORTHWESTERLY FLOW IS
FORECAST TO SWING THROUGH THE NORTHERN PLAINS. HOWEVER, MODEL
DIFFERENCES EXIST IN THE EVOLUTION OF THIS FEATURE. THE GFS HAS BEEN
TRENDING WITH A TIGHTER, FASTER TROUGH; SPINNING UP A RELATIVELY
IMPRESSIVE SURFACE CYCLONE THAT TRAVELS THROUGH ND, NORTHERN MN, AND
INTO LAKE SUPERIOR BY MONDAY AFTERNOON. INTERESTINGLY, THE GFS'S
PRECIP ALONG THE TRAILING COLD FRONT IS RATHER MEAGER COMPARED TO
WHAT ONE WOULD EXPECT WITH SUCH A WOUND UP SYSTEM. ON THE OTHER
HAND, THE ECMWF HAS PERSISTED WITH A SLOWER, WEAKER SOLUTION
DELAYING SURFACE LOW DEVELOPMENT UNTIL THE EARLY MONDAY MORNING OVER
NORTHERN WI. IN TURN, WITH LESS SURFACE ORGANIZATION THE ECWMF JUST
LAZILY MOVES A COLD FRONT WITH WIDESPREAD, LIGHT PRECIP THROUGH
MN/WI. NBM PRODUCES 20-30% POPS ACROSS THE REGION SUNDAY NIGHT INTO
MONDAY AFTERNOON ALONG THE FRONT. WITH STILL UNCERTAINTY WITH PRECIP
TIMING AND COVERAGE, HAVE OPTED TO NOT MAKE ANY CHANGES. REGARDLESS,
QPF AMOUNTS SHOULD BE RATHER LIGHT WITH MAYBE A TENTH OR TWO OF AN
INCH FORECAST. IT SHOULD BE MENTIONED THAT LIGHT SNOW IS POSSIBLE
DURING THE NIGHTTIME/MORNING HOURS WHEN TEMPERATURES ARE COOLEST
BEFORE A CHANGEOVER TO RAIN OCCURS.
MONDAY AND TUESDAY ALSO LOOK PRETTY COOL AS ANOTHER SHOT OF ARCTIC
AIR FOLLOWS THE COLD FRONT. HAVE LOWERED HIGH TEMPERATURES RATHER
SUBSTANTIALLY TO THE NBM 50TH PERCENTILE BASED ON LATEST MODEL
TRENDS, RESULTING IN HIGHS OF UPPER 30S TO MID 40S ACROSS THE CWA.
IT REMAINS TO BE SEEN HOW LONG WE WILL STAY STUCK IN THIS COOL
PATTERN, AS NORTHWEST FLOW LOOKS TO CONTINUE PAST MID-NEXT WEEK.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 634 PM CDT WED APR 14 2021
BREAKS IN THE STRATUS DECK TO VFR WILL FILL BACK IN DURING THE FIRST
FEW HOURS OF THE TAF PERIOD, WITH SITES THEN LOWERING TO IFR
OVERNIGHT. SHOWER ACTIVITY AT EASTERN SITES WILL DECAY AFTER
NIGHTFALL. NORTHWEST WINDS WILL PREVAIL THROUGH THE PERIOD, WITH
GUSTS DIMINISHING AFTER 03Z AND SPEEDS IN THE 8-12 KNOT RANGE FOR THE
REST OF THE PERIOD.
KMSP...SHOWERS WILL END BY 03Z, WITH CONDITIONS LOWERING BELOW 1700
FEET AFTER THAT, AND BELOW 1000 FEET AROUND DAYBREAK. VFR LOOKS TO
DEVELOP BY LATE MORNING.
/OUTLOOK FOR KMSP/
FRI...CHC MVFR CIGS. WINDS N 10KTS.
SAT...VFR. WINDS N 10-15KTS.
SUN...VFR. WINDS NW 10-15KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
SHORT TERM...CTG
LONG TERM...MPG
AVIATION...LS
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