928
FXUS63 KMQT 212330
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
730 PM EDT TUE MAY 21 2019
SHORT TERM
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM EDT TUE MAY 21 2019
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW AND TROUGH OVER
THE SOUTHERN ROCKIES AND ANOTHER IN THE PACIFIC NW AND ANOTHER OVER
ERN CANADA THIS MORNING. THE CLOSED LOW IN THE SOUTHERN ROCKIES WILL
MOVE OUT INTO THE CENTRAL PLAINS AND WILL THEN HEAD NORTH INTO THE
NORTHERN PLAINS ON WED. DEEPER MOISTURE AND 850-500 MB Q-VECTOR
CONVERGENCE MOVES INTO THE AREA AFTER MIDNIGHT AND REMAINS THROUGH
00Z THU. OVERALL, DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST. HAVE THE FAR EAST DRY THROUGH 11Z TONIGHT AND MOST OF THE
PCPN GETS STARTED AFTER 06Z TONIGHT. DID KEEP A POSSIBILITY OF SOME
THUNDER IN THE AREA WED AFTERNOON.
LONG TERM
(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 306 PM EDT TUE MAY 21 2019
A BUILDING PACIFIC RIDGE, AS SEEN BY GFS 500MB HEIGHT ANOMALIES,
WILL ASSIST IN KEEPING AN UPPER-LEVEL CUTOFF LOW IN THE DESERT SW
TOWARDS THE END OF THE MONTH. THIS PATTERN IS EXPECTED TO KEEP THE
CENTRAL CONUS COOLER AND WETTER THAN NORMAL INTO JUNE AS
PRECIPITATION FINDS A WAY INTO UPPER MICHIGAN EVERY 24 TO 36 HOURS.
THANKFULLY, A SURFACE HIGH PRESSURE SYSTEM MOVES IN THIS WEEKEND
FROM THE CANADIAN PRAIRIES TO BLOCK OFF MOST PRECIPITATION CHANCES,
GIVING THE UP A WELL-DESERVED BREAK FROM RAIN FOR MEMORIAL DAY
WEEKEND.
OVERNIGHT WEDNESDAY INTO THURSDAY, EXPECT A BRIEF PERIOD OF SHOWERS
AND A CHANCE AT A FEW RUMBLES OF THUNDER AS A BROAD AREA OF PVA AND
ISENTROPIC ASCENT MOVE THROUGH THE UP. KEPT POPS AND THUNDER AT CHC
GIVEN WEAK AREA OF LIFT AND LATEST NAM RUNS HAVE TRENDED AWAY FROM
RAIN AND THUNDER. GIVEN THAT THE UPPER-LEVEL LOW WEAKENS AS IT
PROGRESSES TOWARDS UPPER MICHIGAN, HAVE TAKEN WINDS DOWN SLIGHTLY
FROM THE PREVIOUS FORECAST.
BEYOND WEDNESDAY NIGHT, THE NEXT ROUND OF PRECIPITATION LOOKS TO BE
ON FRIDAY. A BROAD UPPER LOW MOVES INTO THE DAKOTAS, EJECTING A FAIR
AMOUNT OF PVA AND WAA INTO UPPER MICHIGAN. THIS PRECIPITATION WILL
BE FED BY A 45KT LLJ, REACHING UPPER MICHIGAN MIDDAY FRIDAY.
FORTUNATELY FOR THE UP, MOISTURE AND LIFT TIMING SEEM TO BE
SEPARATED FROM EACH OTHER FOR NOW. PWAT VALUES REMAIN MODEST NEAR 1
INCH ALONG THE WI BORDER, WITH SOME MODELS PRODUCING CLOSER TO 1.25
INCHES. STILL SOME UNCERTAINTY ON THE EXACT TRACK WITH THIS SYSTEM
AS A SPLIT IN THE PRECIPITATION SHIELD IS ANALYZED ON THE GFS AND
GEM CREATING TWO SEPARATE AXISES OF QPF. THIS SOLUTION WOULD LEAD TO
THE ARROWHEAD OF MN AND ALONG THE GRB/MKX CWA BORDER RECEIVING CLOSE
TO AN 1+ INCHES OF RAIN, AS THE UP GETS CLOSER TO 0.25 INCHES. FOR
NOW, TRENDING TOWARDS A GEM/GFS BLEND, KEEPING QPF AROUND 0.2-0.3
INCHES.
AFTER FRIDAY, A SURFACE HIGH PRESSURE SYSTEM MOVES IN FROM CANADA,
WHICH WILL DELAY AN APPROACHING LOW FROM THE CENTRAL PLAINS. WITHIN
THIS HIGH PRESSURE SYSTEM, GFS ANALYZES AN EMBEDDED SHORTWAVE MOVING
ACROSS UPPER MICHIGAN ON SUNDAY. THIS WOULD GIVE THE UP A QUICK
SHOWER OR TWO ON A GENERALLY SUNNY WEEKEND. AS THIS HIGH MOVES OUT
ON MONDAY, A LOW PRESSURE SYSTEM WILL TRACK NORTHEAST TOWARDS THE
GREAT LAKES BRINGING A BROAD AREA OF PRECIPITATION TO THE UPPER
GREAT LAKES ON TUESDAY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 729 PM EDT TUE MAY 21 2019
VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT. LLWS IS
EXPECTED AS SOUTHEAST WINDS INCREASE ABOVE THE BOUNDARY LAYER.
CONDITIONS WILL DROP TO MVFR WED MORNING AT ALL SITES AS RAIN MOVES
IN. ISOLATED THUNDERSTORMS MAY BE POSSIBLE WEDNESDAY AFTERNOON BUT
THE PROBABILITY IS TOO LOW FOR MENTION IN THE TAF.
MARINE
(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 239 PM EDT TUE MAY 21 2019
AS A LOW PRESSURE SYSTEM APPROACHES THE UPPER GREAT LAKES REGION
LATER TONIGHT, WINDS WILL BE ON THE INCREASE UP TO 30 KNOTS ACROSS
THE WESTERN HALF TO TWO-THIRDS OF THE LAKE. GETS CLOSE TO GALE, BUT
JUST UNDER AND DROPPED THE GALE WATCH FOR THIS REASON. THIS WOULD BE
THE STRONGEST WINDS IN THIS FORECAST. OTHERWISE THE WIND WILL STAY
AT OR BELOW 20 KNOTS FOR THE REST OF THE FORECAST PERIOD.
MQT WATCHES/WARNINGS/ADVISORIES
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
SHORT TERM...07
LONG TERM...JAW
AVIATION...JLB
MARINE...07
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