National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KAPX 210526
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
126 AM EDT MON APR 21 2014

.SYNOPSIS...
ISSUED AT 400 PM EDT SUN APR 20 2014

LOW PRESSURE PASSING WELL NORTH OF THE STATE WILL DRAG A WEAK COLD
FRONT INTO NORTHERN MICHIGAN. THAT FRONT WILL STALL OVER THE
AREA...UNTIL ANOTHER LOW CROSSES LOWER MICHIGAN MONDAY AFTERNOON.
OUR WEATHER WILL REMAIN ON THE DAMP SIDE THROUGH MONDAY EVENING. WE
WILL COOL OFF BUT DRY OUT AFTER THAT...WITH A LENGTHY PERIOD OF
BELOW NORMAL TEMPERATURES EXPECTED.

&&

.UPDATE...
ISSUED AT 124 AM EDT MON APR 21 2014

THE 500 MB VORT MAX IS MOVING OFF THE SHORELINE, SO WILL BE
LOWERING THE POPS FOR THE NEXT FEW HOURS ALONG THE M-55/M-72
CORRIDORS. THE RAIN SHOWERS NORTH OF M-32 LOOK OKAY FOR THE TIME
BEING.

UPDATE ISSUED AT 1124 PM EDT SUN APR 20 2014

WE CONTINUE TO REFINE POPS AND WEATHER THROUGH THE OVERNIGHT AS
MCV IS NOW POSITIONED OVER OUR SOUTHEAST ZONES...WITH
SCATTERED/NUMEROUS SHOWERS IN IT/S VICINITY...AS WELL AS NEAR THE
BETTER LLEVEL MOISTURE PLUME OVER THE TIP OF THE MITT. WHILE
ACTIVITY SHOULD WANE A LITTLE AS THIS PASSES EAST...UPSTREAM RADAR
TRENDS SUGGEST A CONTINUATION OF OCCASIONAL SHRAS THAT SHOULD
PIVOT INTO THE AREA FOR THE REMAINDER OF THE OVERNIGHT.

GIVEN LATE EVENING OBS...HAVE CONCERNS ABOUT DEVELOPING DENSE FOG
POTENTIAL OVER EASTERN UPPER GIVEN PARTIAL CLEARING AND LOW
TEMP/DEWPOINT SPREADS. RECENT 00Z MET AND 02Z LAV GUIDANCE AGREE
AND WILL ADD MENTION TO HWO AND ISSUE AN SPS FOR THE REMAINDER OF
THE OVERNIGHT TO HIGHLIGHT THIS POTENTIAL.

NO OTHER SIGNIFICANT CHANGES NEEDED AT THIS TIME.

UPDATE ISSUED AT 830 PM EDT SUN APR 20 2014

AS LEAD EDGE OF MESOVORT MOVES INTO NORTHWEST LOWER...HAVE SEEN AN
UPTICK IN SHRA ACTIVITY OVER THE STRAITS...WHERE THE BEST LLEVEL
MOISTURE TONGUE REMAINS IN PLACE. HAVE BOOSTED POPS HERE THROUGH
THE NEXT 2-3 HOURS UNTIL THIS MID LEVEL FORCING SHIFTS EAST.
EXPECT THAT WE MAY TRANSITION INTO A RELATIVE LULL AFTER THIS
FEATURE PASSES TO OUR EAST. WITH ADDITIONAL CONVECTIVE DEVELOPMENT
OVER IOWA...HOWEVER...EXPECT RENEWED PRECIPITATION CHANCES
OVERNIGHT AND THUS ONGOING FORECAST LATER TONIGHT LOOKS GOOD.

NO OTHER CHANGES NEEDED AT THIS TIME.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 400 PM EDT SUN APR 20 2014

...PERIODIC SHOWERS NORTHERN LOWER/DRIZZLE GIVING WAY TO FOG EASTERN
UPPER...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL. FOG DEVELOPMENT POSSIBLE
EASTERN UPPER OVERNIGHT WITH CONCOMITANT REDUCED VISIBILITIES.

PATTERN SYNOPSIS/FORECAST: AFTERNOON SURFACE/COMPOSITE ANALYSIS
SHOWS LOW PRESSURE WELL TO THE NORTH OF THE UPPER GREAT LAKES OVER
NORTHERN ONTARIO...REMNANT OLD FRONTAL BOUNDARY EXTENDS SOUTH IN
CENTRAL UPPER MICHIGAN AND BECOMES A LITTLE BETTER DEFINED OVER
NORTHERN PORTIONS OF IOWA/WISCONSIN.  NORTHEAST-SOUTHWEST ORIENTED
THETA-E RIDGE AXIS JUST AHEAD OF THIS FRONT HAS BEEN FEEDING A BAND
OF RAIN THAT HAS BEEN FOCUSED MOSTLY ON THE STRAITS/TIP OF THE MITT
REGION THROUGH THE DAY...AND EXTENDS BACK SOUTHEAST INTO NORTHEAST
IOWA WHERE THUNDERSTORMS HAVE BEEN FEEDING THE BACK END OF THE LINE
(WHERE A SMALL CONVECTIVELY INDUCED VORTICITY MAXIMUM RESIDES AND IS
TRACKING EAST-NORTHEAST ACROSS SOUTHERN WISCONSIN).  SUNSHINE HAS
BEEN PREVALENT OVER THE SOUTHEAST QUARTER OF THE FORECAST AREA WHERE
TEMPERATURES HAVE WARMED WELL INTO THE 60S...WHILE UNDER THE CLOUDS
AND RAIN TEMPERATURES ACROSS EASTERN UPPER HAVE STRUGGLED TO GET OUT
OF THE 30S (THOUGH STARTING TO GET SOME BREAKS OPENING UP OVER LUCE
COUNTY).

CURRENT RADAR TRENDS SUGGEST PRECIPITATION FOCUS WILL SHIFT THIS
EVENING FROM THE TIP OF THE MITT COUNTIES TO THE M-32 CORRIDOR AND
POINTS SOUTH...WHILE BACKING MID LEVEL WINDS ADVECT DRIER AIR ACROSS
THE UPPER PENINSULA.

PRIMARY FORECAST CONCERNS: PRECIPITATION EVOLUTION...PARTICULARLY
PERSISTENCE...ACROSS NORTHERN LOWER MICHIGAN.  FOG DEVELOPMENT
ACROSS EASTERN UPPER LATER.

TONIGHT: PERSISTENT THETA-E RIDGE AXIS WILL REMAIN DRAPED ACROSS
NORTHERN MICHIGAN...THUS THE POTENTIAL FOR CONTINUED SHOWER
DEVELOPMENT WILL CONTINUE THROUGH THE NIGHT.  BUT WITHOUT A
SIGNIFICANT FOCUSING MECHANISM DIFFICULT TO ASCERTAIN HOW PERSISTENT
PRECIPITATION MAY BE...AND THUS QPF IS SOMEWHAT PROBLEMATIC GIVEN
QUASI-TRAINING NATURE OF SHOWER PROPAGATION.  INITIALLY LOOKS LIKE
APPROACHING MESO-VORTICITY CENTER WILL BE THE MAIN FOCUS INTO THE
EARLY EVENING HOURS...THOUGH SOME DRIZZLE ALSO NOTED ACROSS EASTERN
UPPER AND THAT WILL LIKELY BE AN ISSUE THIS EVENING (AND ACROSS THE
TIP OF THE MITT INTO THE EARLY MORNING HOURS WITH BETTER THREAT FOR
MEASURABLE PRECIPITATION FARTHER SOUTH).  WILL NOT ATTEMPT TO GET
CUTE WITH PRECIPITATION TIMING GIVEN BROAD UNFOCUSED NATURE OF
FORCING...SCATTERED/OCCASIONAL SHOWERS (WITH PERIODS OF DRIZZLE
ACROSS EASTERN UPPER/FAR NORTHERN LOWER) WILL HAVE TO SUFFICE.
ANTICIPATE THAT CLOUDS WILL THIN NORTH OF THE BRIDGE LATER
TONIGHT...AND WITH LIGHT WINDS AND ALREADY SMALL DEW POINT
DEPRESSIONS  (2-5F ACROSS EASTERN UPPER) FOG DEVELOPMENT LOOKS
INCREASINGLY LIKELY.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 400 PM EDT SUN APR 20 2014

HIGH IMPACT WEATHER POTENTIAL: IMPACTS OF RAINFALL ON ALREADY
ABNORMALLY HIGH RIVER LEVELS.

LARGER SCALE OVERVIEW: A MESS. THAT ESSENTIALLY DESCRIBES THE LONG
WAVE PATTERN IN THE COMING DAYS...ESPECIALLY AS WE HEAD TOWARD THE
MIDDLE AND END PORTIONS OF THE MID TERM PERIOD. INITIAL ZONAL FLOW
REGIME DEFINITELY EXPECTED TO TREND TOWARDS ONE OF MORE
AMPLIFICATION THROUGH COMBINATION OF STRONG PACIFIC JET CORES AND
STILL PROGGED RAPID DEVELOPMENT OF NEGATIVE NORTH ATLANTIC
OSCILLATION. THE FORMER LOOKS TO KEEP THE PATTERN RESPECTABLY
ACTIVE...WHILE THE LATTER THEORETICALLY SHOULD HELP DRIVE THE
AMPLIFICATION PROCESS INTO HIGH GEAR. UNFORTUNATELY...ABOVE
PROCESSES ARE ALSO ONE WHICH OFTEN DRIVE SIGNIFICANT INTRA AND INTER
MODEL INCONSISTENCIES. SO...WHILE CONFIDENCE REMAINS RATHER HIGH
EARLY ON IN THE FORECAST...THE SAME DEFINITELY CANNOT BE SAID FROM
THE MID-WEEK PERIOD ONWARD.

PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE AND CLOUD TRENDS
THROUGHOUT THE FORECAST. ACCESSING TIMING/COVERAGE/AND AMOUNT OF
RAINFALL THROUGH THE PERIOD AND POSSIBLE IMPACTS OF SUCH ON AREA
RIVERS.

DETAILS: STILL GOING TO BE DEALING WITH CURRENT RAIN PRODUCING NEAR
STATIONARY FRONTAL SYSTEM TO START THE WORK WEEK. ASSOCIATED
CONVERGENCE LOOKS TO GET RE-ENERGIZED AS MID LEVEL HEIGHT FALLS
ASSOCIATED WITH APPROACHING SHORTWAVE TROUGH AND NICE CORRIDOR OF
RER UPPER JET DYNAMICS OVER TOP THE FRONTAL AXIS. ABOVE SHOULD NO
DOUBT SPAWN A SURFACE WAVE THAT WILL RIDE UP AND ALONG THE FRONT
MONDAY INTO MONDAY NIGHT. STILL PLENTY OF GUIDANCE DEBATE ON JUST
HOW ABOVE EXACTLY UNFOLDS...WHICH IS REALLY NO SURPRISE GIVEN DUAL
SHORTWAVE TROUGH STRUCTURE EXPECTED TO MOVE INTO THE WESTERN LAKES
MONDAY. RAINS APPEAR A PRETTY SAFE BET ACROSS NORTHERN LOWER WHERE
ORIGINAL LOW LEVEL SURFACE FRONT WILL RESIDE. PLENTY OF QUESTIONS
FURTHER NORTH...WITH CONCERNS MOISTURE ADVECTION WILL BE "CUT-OFF"
BY LOWER MICHIGAN FRONT...NEVER DIRECTLY LINKING WITH APPROACHING
RATHER STRONG NORTHERN MID LEVEL WAVE. ABOVE KINDA MAKES SENSE...
ALTHOUGH DO FEEL LATEST NAM-WRF/GFS PROGS ARE A TOUCH TOO AGGRESSIVE
WITH THEIR SOUTHERN SOLUTIONS GIVEN STRENGTH OF APPROACHING NORTHERN
WAVE. ACTUALLY REALLY LIKE INHERITED FORECAST KEEPING HIGHEST RAIN
THREAT ACROSS THE SOUTH...WHILE LEAVING SOME CHANCY POPS A TOUCH
FURTHER NORTH UP INTO THE STRAITS. MAIN SLUG OF RAIN EXPECTED TO
PULL STEADILY OFF TO THE EAST EARLY MONDAY EVENING. SOME CONCERN FOR
A PERIOD OF DRIZZLE OR FLURRIES DEVELOPING OVERNIGHT MONDAY INTO
TUESDAY MORNING AS SLUG OF LOW LEVEL MOISTURE PIVOTS SOUTH ACROSS
THE AREA WITH PASSAGE OF MAIN MID LEVEL WAVE. WILL INTRODUCE THIS
IDEA...TARGETING FAVORED UPSLOPE AREAS INTO THE HIGHER TERRAIN FOR
BETTER COVERAGE. TEMPERATURES REMAIN A FORMIDABLE CHALLENGE...
ESPECIALLY MONDAY. WARM SECTOR AREAS SOUTH OF THE FRONT WILL HAVE NO
PROBLEM REACHING WELL INTO THE 60S ONCE AGAIN...WITH EVEN A FEW
LOWER 70S POSSIBLE BARRING WIDESPREAD RAINS. DEFINITELY SEVERAL
DEGREES COOLER ACROSS EASTERN UPPER WHERE EAST TO SOUTHEAST FLOW
WILL BE MAINTAINED...KEEPING THAT AREA IN THE 40S AND 50S.
TEMPERATURES ACROSS THE NORTH HALF OF NORTHERN LOWER DIRECTLY TIED
TO EXACT FRONTAL PLACEMENT AND RAIN COVERAGE...WITH A SEVERAL DEGREE
SPREAD POSSIBLE OVER SHORT DISTANCES AND TIME FRAMES. TOUCH EASIER
TEMPERATURE FORECAST HEADING INTO MONDAY NIGHT AND TUESDAY AS ROUND
OF CAA DEVELOPS. READINGS BY TUESDAY WILL BE SEVERAL DEGREES BELOW
NORMAL (MAINLY IN THE 40S)...WITH GUSTY NORTHWEST WINDS ADDING
CONSIDERABLY MORE CHILL. THROW IN THE POSSIBILITY OF A FEW
SPRINKLES/FLURRIES AND YOU GET THE IDEA...NOT PLEASANT!

RAINFALL AMOUNTS NOT EXPECTED TO GET TOO SIGNIFICANT THROUGH THIS
PERIOD...ESPECIALLY AS ANY DEEP CONVECTION LOOKS TO REMAIN OFF TO
OUR SOUTH AND SOUTHWEST. HPC`S QUARTER TO HALF INCH AMOUNTS LOOK
REASONABLE (SREF PLUMES CONCUR)...WHICH SHOULD BE MORE THAN
MANAGEABLE FOR AREA RIVERS.

DRY MID-WEEK GIVES WAY TO ADDITIONAL RAIN CHANCES TO END THE
WEEK...WITH STRONG GUIDANCE SUPPORT THAT NEXT WAVE CARVES OUT FAIRLY
DEEP NORTHERN PLAINS TROUGHING BY THURSDAY...WHICH SLOWLY SLIDES
ACROSS OUR AREA THROUGH THE START OF THE WEEKEND. LOOKS LIKE BEST
CHANCE FOR WIDESPREAD RAINS OCCURS LATER THURSDAY/THURSDAY NIGHT AS
WAA REGIME SPREADS ACROSS THE NORTHERN LAKES. WILL NEED TO CLOSELY
WATCH THE POTENTIAL FOR INITIAL PRECIP TO FALL AS A TOUCH OF
SNOW...ESPECIALLY ACROSS EASTERN UPPER WHERE EVAP COOLING WILL BE
MAXIMIZED. PATTERN CURRENTLY ARGUES FOR MORE OF A SHOWERY THREAT
THERE-ON-AFTER AS UPPER TROUGHING OVERSPREADS THE AREA. CONFIDENCE
REALLY WAVERING ON DEPTH OF THIS TROUGHING/ASSOCIATED POCKET OF COLD
AIR...WITH AT LEAST SOME HINTS STOUT CANADIAN PRAIRIE RIDGE BUILDING
HELPS REALLY DEEPEN SUCH. SOME OF THE COLDER SOLUTIONS DEFINITELY
SUPPORTS MIXED PRECIP CONCERNS ONCE AGAIN HEADING THROUGH FRIDAY
NIGHT AND SATURDAY. TOO MUCH PRECIP WORDING FOR MY LIKING...SO WILL
KEEP THE SECOND HALF OF THE WEEKEND DRY. THIS...HOWEVER...IS SUBJECT
TO CHANGE BASED ON SPEED OF PATTERN PROGRESSION. PLENTY OF TIME TO
REVISIT ALL THE ABOVE IN THE COMING DAYS...AND SIGNIFICANT CHANGES
ARE NOT ONLY POSSIBLE...BUT ARE EXPECTED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 121 AM EDT MON APR 21 2014

SUMMARY: A WEAK FRONTAL BOUNDARY WILL REMAIN OVER NORTHERN MICHIGAN
THROUGH THE DAY MONDAY BEFORE LOW PRESSURE MOVES ACROSS THE STATE
MONDAY EVENING...AND THEN EAST OF THE AREA OVERNIGHT MONDAY NIGHT.
DETERIORATING FLYING CONDITIONS ARE EXPECTED THROUGH THE UPCOMING
TAF PERIOD.

RESTRICTIONS: VFR CONDITIONS CONTINUE AT THIS TIME /EXCEPT MVFR AT
PLN/...AND CONTINUE TO SEE TRENDS SUGGESTING THAT ANY DETERIORATION
IN FLYING CONDITIONS WILL BE DELAYED UNTIL LATER MONDAY /OUTSIDE OF
FOG-STRATUS POTENTIAL AT PLN TOWARDS DAYBREAK/. EXPECT SCATTERED TO
NUMEROUS SHOWERS TO CONTINUE THROUGH DAYBREAK WITH VFR CONDITIONS
CONTINUING AT MBL/TVC/APN AS PLN SEES MVFR/IFR VSBYS AND CIGS IN
DEVELOPING FOG.

FOR THE DAY ON MONDAY...EXPECT ISOLATED/SCATTERED SHOWER COVERAGE
THROUGH THE MORNING FOR ALL TERMINALS WITH INCREASING CONFIDENCE
THAT OUTSIDE OF PLN /IFR CIGS-MVFR VSBYS/ ALL SITES SHOULD REMAIN VFR.
THIS WILL LIKELY CHANGE BY AFTERNOON/EVENING...HOWEVER...AS SHOWER
ACTIVITY BECOMES MORE WIDESPREAD WITH MVFR RESTRICTIONS LIKELY BOTH
DUE TO VSBYS AND CIGS.  THIS SHRA ACTIVITY WILL EXIT MONDAY NIGHT
LEAVING SOME SCATTERED SHRAS AND LIKELY CONTINUED MVFR /AND
POTENTIALLY IFR/ CIGS.

WINDS: CALM WINDS OVERNIGHT WILL REMAIN LIGHT/VARIABLE THROUGH
MONDAY MORNING BEFORE BECOMING WEAK SOUTHWESTERLY /5-10KTS/ DURING
THE MID/LATE MORNING MONDAY /EXCEPT STILL LIGHT-VARIABLE AT PLN/.
WINDS WILL SHIFT SOUTHEASTERLY 5-10KTS DURING THE AFTERNOON AT APN
GIVEN LAKE BREEZE DEVELOPMENT.  BY MONDAY AFTERNOON/EVENING...A
SHIFT TO NORTHWESTERLY WINDS AROUND 5-10KTS IS EXPECTED...WITH THIS
OVERSPREADING ALL TERMINALS AND CONTINUING THROUGH THE END OF THE
TAF PERIOD.

LLWS: NO THREAT THIS CYCLE.

THUNDER: A LOW CHANCE OF THUNDER IS POSSIBLE THROUGH THE AFTERNOON
FOR TVC/APN/MBL WITH THE BEST CHANCES OVER CENTRAL AND SOUTHERN
MICHIGAN.  AT THIS TIME...PROBABILITIES THIS FAR NORTH ARE TOO LOW
TO WARRANT INCLUSION IN THIS TAF PACKAGE.


&&

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

&&

$$

UPDATE...JL
SYNOPSIS...JZ
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...ARNOTT