Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 230136
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
936 PM EDT TUE APR 22 2014

.SYNOPSIS...
ISSUED AT 259 PM EDT TUE APR 22 2014

HIGH PRESSURE WILL GRADUALLY BUILD INTO THE GREAT LAKES REGION
TONIGHT AND WEDNESDAY BRINGING MUCH DRIER CONDITIONS TO THE STATE.
THE NEXT CHANCE FOR PRECIPITATION COMES LATE THURSDAY AND THURSDAY
NIGHT AS LOW PRESSURE MOVES INTO THE GREAT LAKES. THERE IS A CHANCE
OF SOME WET SNOW WITH THIS SYSTEM ACROSS THE UPPER PENINSULA.  COOL
TEMPERATURES WILL CONTINUE THROUGH THE UPCOMING WEEKEND.

&&

.UPDATE...
ISSUED AT 936 PM EDT TUE APR 22 2014

STRONG HIGH PRESSURE AND VERY DRY LOW-LEVEL AIR LOOM JUST TO OUR
NW. CLEARING HAS BEEN MAKING UNSTEADY PROGRESS ACROSS SUPERIOR AND
CENTRAL UPPER MI...AND SUBSTANTIAL CLEARING WILL OCCUR IN NORTHERN
MI OVERNIGHT. NO MAJOR CHANGES THERE. HAVE HAD TO STRETCH OUT
FLURRY/DRIZZLE WORDING A FEW HOURS (WE CONTINUE TO SEE A FEW
FLAKES HERE AT THE OFFICE). MIN TEMPS REMAIN A POINT OF
CONCERN...ONLY GOING CIRCA 10F BELOW CURRENT READINGS WHEN
CLEARING IS EXPECTED. HOWEVER...PRESSURE GRADIENT WILL SUPPORT
THE BL STAYING COUPLED FOR AT LEAST A LITTLE BIT PAST WHEN WE
CLEAR. THAT WILL HELP SUPPORT MIN TEMPS. WILL STILL LOWER 1-2F IN
SPOTS...ESPECIALLY FAR NORTHERN LOWER MI.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 259 PM EDT TUE APR 22 2014

...MUCH COOLER TEMPERATURES HERE TO STAY...

HIGH IMPACT WEATHER POTENTIAL: NONE.

PATTERN SUMMARY: THIS FORECASTER PREFERS THE WEATHER OF 24 HOURS
AGO...BUT A COOL REALITY HAS SET IN ACROSS NORTHERN MICHIGAN OVER
SINCE THEN...AND WILL REMAIN WITH US FOR THE FORESEEABLE FUTURE.
EARLY AFTERNOON COMPOSITE ANALYSIS REVEALS A TRIO OF SHORTWAVES
EMBEDDED WITHIN SOMEWHAT LARGER SCALE TROUGHING THAT IS NOW PASSING
EAST OF THE GREAT LAKES REGION.  THE SOUTHERN TWO OF THESE FEATURES
HAS INTERACTED WITH SHALLOW BOUNDARY LAYER MOISTURE...LLEVEL
CYCLONIC FLOW AND SOME TOPOGRAPHICAL FORCING TO PRODUCE A
SIGNIFICANT AREA OF LOW CLOUDS AND LIGHT SNOW/DRIZZLE ACROSS
NORTHERN MICHIGAN. AT THE SURFACE...HIGH PRESSURE OVER THE UPPER
MISSISSIPPI VALLEY WILL SLOWLY BUILD INTO NORTHERN MICHIGAN. THIS
FEATURE PROMISES IMPROVEMENT TO OUR WEATHER...BUT WITH MOISTURE
CURRENTLY TRAPPED BENEATH A SUBSIDENCE INVERSION...THIS PROCESS WILL
LIKELY BE SLOW.

PRIMARY FORECAST CONCERNS: CLOUD TRENDS OVERNIGHT AND THE
RESULTANT IMPACT ON TEMPERATURES.

THROUGH THIS EVENING: IMPRESSIVE VORTMAX ARRIVING AT THE MOMENT
ALLOWING FOR AN UPTICK IN RADAR RETURNS THIS AFTERNOON ACROSS
NORTHERN LOWER MICHIGAN AS INVERSION HEIGHTS DEEPEN SOMEWHAT.  THIS
IS RESULTING IN A TRANSITION FROM DRIZZLE BACK TO SNOW OVER THE HIGH
TERRAIN OF NORTHERN LOWER.  CAN/T RULE OUT A FEW SPOTS SEEING A
COATING ON GRASSY SURFACES...BUT OF LITTLE CONSEQUENCE.

TONIGHT: WITH AFOREMENTIONED SHORTWAVE DEPARTING...EXPECT ANY
REMAINING DRIZZLE/SHSN ACTIVITY TO END WITH CONCERNS TURNING TO
CLOUD COVER AS HIGH PRESSURE GRADUALLY BUILDS INTO THE AREA TURNING
LLEVEL WINDS INCREASINGLY ANTICYCLONIC.  CURRENTLY TRACKING CLEARING
LINE NOW WELL NORTH OF LAKE SUPERIOR...AND WHILE SOME HOLES WILL
LIKELY DEVELOP DURING THE FIRST HALF OF THE NIGHT...EXPECT FULL
CLEARING TO WAIT UNTIL AFTER MIDNIGHT WHEN THIS CLEARING ARRIVES.

WINDS:  RESIDUAL NORTH-NORTHWESTERLY GRADIENT REMAINS IN PLACE
OVERNIGHT SHOULD ALLOW MOST LOCATIONS TO REMAIN COUPLED...WITH 10KT
WINDS THROUGH THE EVENING...AND THEN 5KTS AFTER MIDNIGHT.

TEMPERATURES /CONFIDENCE: MODERATE/: CERTAINLY DEPENDENT ON
CLEARING...BUT WITH THE COUPLED FLOW MENTIONED ABOVE...EXPECT LOWS
NOT TO GET TOO OUT OF HAND.  MAV/MET GUIDANCE SUGGEST LOWS COULD
FALL AS FAR AS 20...BUT THIS SEEMS A BIT LOW GIVEN THE GRADIENT AND
VERY LATE CLEARING /AND EARLY SUNRISE/.  LIKE THE EXPERIMENTAL ECMWF
MOS WHICH SUGGESTS LOWER 20S OVER EASTERN UPPER AND MID/UPPER 20S
OVER NORTHERN LOWER.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 259 PM EDT TUE APR 22 2014

...COOLER THAN NORMAL WEATHER CONTINUES...

HIGH IMPACT POTENTIAL: LOW.

LARGER SCALE OVERVIEW:  QUASI-ZONAL FLOW BECOMES MORE AMPLIFIED THIS
WEEK WITH INCREASING PACIFIC JET ENERGY AND DEVELOPMENT OF NEGATIVE
NAO.  HIGH LATITUDE BLOCKING ALSO BEGINS TO TAKE SHAPE FROM
GREENLAND INTO THE CANADIAN MARITIMES...HELPING TO PUSH UNSEASONABLY
COLD AIR INTO THE GREAT LAKES /HAVE YOU HEARD THIS BEFORE?/.

PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE AND CLOUD TRENDS
THROUGHOUT THE FORECAST.  LOW RH VALUES AND FIRE WEATHER CONCERNS ON
WEDNESDAY.  TIMING/COVERAGE/AND AMOUNT OF RAINFALL FOR THE END OF
THE WEEK AND POSSIBLE IMPACTS ON AREA RIVERS.  PRECIPITATION TYPE
QUESTIONS FOR LATE THURSDAY/THURSDAY EVENING OVER EASTERN UPPER.

DETAILS:  LOW AMPLITUDE RIDGING SLIDES ACROSS THE GREAT LAKES ON
WEDNESDAY WITH PLENTY OF SUNSHINE BUT STILL BELOW NORMAL
TEMPERATURES. DEEP LAYER DRY AIR WILL MIX AFTERNOON RH VALUES DOWN
INTO THE TEENS EAST OF INTERSTATE-75 IN DOWNSLOPE FAVORED
AREAS. WILL HIGHLIGHT THIS FIRE WEATHERWISE IN THE FIRE WEATHER
PLANNING FORECAST.  SLOWLY DEPARTING H8 THERMAL TROUGH WITH H8
TEMPS IN THE NEGATIVE SINGLE DIGITS. SO DESPITE DEEP MIXING AND A
STRONG LATE APRIL SUN...HIGHS RANGING FROM THE MID 40S NORTH TO
MID 50S SOUTH /BELOW NORMAL/. LITTLE IN THE WAY OF DIURNAL CUMULUS
EXPECTED GIVEN VERY DRY SFC DWPTS.

INCREASING MID/HIGH CLOUDS LATE WEDNESDAY NIGHT INTO THURSDAY WITH
DEVELOPING WARM AIR ADVECTION AHEAD OF APPROACHING SFC LOW AND UPPER
TROUGH.  STILL SOME MODEL DIFFERENCES ON HOW MUCH PRECIPITATION WILL
BE REALIZED WITH THIS FIRST PUSH OF WARM AIR ADVECTION EARLIER IN
THE DAY.  INITIALLY DRY AMBIENT AIRMASS...BUT TOP DOWN MOISTENING
DURING THE AFTERNOON/EARLY EVENING RESULTING IN RAIN DEVELOPING /ESPECIALLY
WEST/. SURFACE LOW COMES ACROSS NORTHERN LOWER MICHIGAN THURSDAY
NIGHT WITH MORE FAVORABLE H3 DIVERGENCE SIGNAL...UPPER DIFFLUENCE
AND LOW LEVEL SURFACE CONVERGENCE...LEADING TO WIDESPREAD RAIN.
SNEAKY WET SNOW POTENTIAL OVER PORTIONS OF EASTERN UPPER WITH
PERSISTENT DRIER EASTERLY FLOW HELPING TO FEED DYNAMIC COOLING OF
THE COLUMN /EVAP COOLING/. WILL NOT GET TOO DETAILED THIS FAR
OUT...BUT WILL INTRODUCE RAIN/SNOW WORDING INTO THE FORECAST.
STILL NOT MUCH INSTABILITY TO SPEAK OF...SO THUNDER CHANCES REMAIN
LOW. RAINFALL AMOUNTS UP TO 0.50 INCHES. SURFACE LOW SLOWLY
DEPARTS ON FRIDAY WITH WIDESPREAD PRECIPITATION BECOMING MORE
SHOWERY. TRICKY TEMPERATURE FORECAST ON FRIDAY GIVEN BAROCLINIC
ZONE ACROSS THE AREA...WITH MID 40S NORTH TO NEAR 60 SOUTH.

MAY SEE A FEW LINGERING SHOWERS EARLY SATURDAY...BUT OVERALL MUCH OF
SATURDAY LOOKS DRY.  RAPIDLY DIMINISHING CONFIDENCE BY SUNDAY INTO
EARLY NEXT WEEK AS PATTERN BECOMES BLOCKY AND MODELS TYPICALLY
STRUGGLE IN THESE TYPES OF SITUATIONS.  ANOTHER LARGE SLOW MOVING
TROUGH OVER THE CENTER OF THE COUNTRY WITH RAIN POSSIBILITIES ON THE
DOORSTEP OF OUR AREA.  THE RAIN WILL BATTLE WITH DRY EASTERLY FLOW
OVER THE NORTHERN LAKES WITH HUDSON BAY HIGH TO THE NORTH.  WILL GO
WITH SOME LOW POPS OVER SOUTHERN AREAS AND KEEP NORTHERN AREAS DRY.
TEMPERATURES SLOWLY MODIFY BUT STILL REMAIN BELOW NORMAL FOR THE
END OF APRIL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 732 PM EDT TUE APR 22 2014

MVFR CIGS AT TIMES THIS EVENING...THEN VFR.

COOL HIGH PRESSURE IN NW ONTARIO WILL SLOWLY BUILD INTO THE ACROSS
THE NORTHERN GREAT LAKES THRU WEDNESDAY. MUCH DRIER AIR IS
CROSSING LAKE SUPERIOR...AND WILL RAPIDLY ERODE CLOUD COVER
TONIGHT. A MIX OF VFR AND MVFR CIGS WILL CONTINUE THIS
EVENING...FOLLOWED BY CLEARING TOWARD OR JUST AFTER MIDNIGHT. VFR
CONDITIONS WILL PERSIST FROM THEN THRU THE DAY ON WEDNESDAY.

PRESENTLY GUSTY NW TO N WINDS WILL DIMINISH TONIGHT. THESE WINDS
WILL PICK UP AGAIN A BIT ON WEDNESDAY...THOUGH IT WILL NOT BE AS
WINDY AS TUESDAY WAS.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...ARNOTT
SHORT TERM...ARNOTT
LONG TERM...JK
AVIATION...JZ






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