Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/22/13
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
234 PM MDT SUN OCT 20 2013
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 233 PM MDT SUN OCT 20 2013
IN NW FLOW ALOFT THE INITIAL VORTICITY MAXIMUM HAS PASSED TO THE
SE OF THE STEAMBOAT-VAIL LINE PRODUCING ENHANCEMENT EAST OF VAIL
PASS THIS EARLY AFTERNOON. SNOTELS SHOW 2 INCHES IN THE MTNS EAST
OF STEAMBOAT SPRINGS WITH HIGHER AMOUNTS IN THE PARK RANGE NEAR
THE WYOMING BORDER. SNOW ACCUMULATION LEVEL THIS AFTERNOON IS
AROUND 9KFT THERE. SOME LESS ORGANIZED ENERGY WILL ROLL OVER THE
ELKHEADS-PARK-GORE RANGES THIS AFTERNOON BUT THIS FORCING ENDS BY
SUNSET. LITTLE EXTRA ACCUMULATION IS EXPECTED EXCEPT PERHAPS IN
THE HIGHEST ELEVATIONS OF THE ZIRKEL WILDERNESS. THE 18Z RAP AND
HRRR END SHOWERS BY 6PM BUT THE NAM HOLDS ONTO SOME LIGHT
OROGRAPHIC SNOW ON NORTH-FACING SLOPES INTO THE EVENING. ALL AGREE
ITS ALL DONE BY MIDNIGHT. THEREFORE HAVE CUT BACK POPS FOR
TONIGHT.
SOME LOW-MID CLOUDS WILL LINGER OVERNIGHT MAINLY EAST OF A LINE
FROM CRAIG SOUTH TO MONARCH PASS. OTHERWISE PARTIALLY CLEARING
SKIES WILL KEEP TEMPERATURES BELOW NORMAL TONIGHT AND MONDAY.
WITH THE PASSING OF THESE FINAL DISTURBANCES THIS EVENING THE
WEST COAST RIDGE RELAXES INTO THE INTERMOUNTAIN WEST. BENIGN AND
DRY NW FLOW CONTINUES THROUGH MONDAY NIGHT AND BEYOND.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 233 PM MDT SUN OCT 20 2013
DRY WITH A GRADUAL WARMING TREND AS THE LARGE-SCALE PATTERN CHANGES
LITTLE. A BLOCKING UPPER RIDGE NEAR THE WEST COAST DRIFTS OVER THE
GREAT BASIN BY MIDWEEK BEFORE RETREATING BACK WESTWARD...WHILE A
LARGE TROUGH REMAINS OVER THE CENTRAL AND EASTERN PART OF THE
COUNTRY. NORTHWEST FLOW ON TUESDAY BECOMES WEST TO SOUTHWEST
WEDNESDAY-THURSDAY AS A WEAK WAVE UNDERCUTS THE RIDGE AND CROSSES
THE SOUTHERN GREAT BASIN...SWITCHING BACK TO NORTHWEST FRIDAY AS THE
WAVE PASSES BY TO OUR SOUTH. THIS WILL BRING SOME CLOUDS TO CENTRAL
AND SOUTHERN PARTS OF THE FORECAST AREA BUT LITTLE OR NO
PRECIPITATION...AND WILL KEEP THE FORECAST DRY. DAYTIME TEMPERATURES
WILL BE NEAR TO A LITTLE ABOVE NORMAL WHILE THE NIGHTS AVERAGE NEAR
NORMAL.
AN UPPER LOW IS EXPECTED TO PINCH OFF FROM THE NORTHERN JET
STREAM OVER THE NERN PACIFIC OCEAN AND GRADUALLY SETTLE OFF THE CA
COAST AND UNDERNEATH THE RIDGE BY LATE FRIDAY. MODELS OFTEN HAVE
DIFFICULTY HANDLING THESE CUT-OFF LOWS...AND THE GFS AND ECMWF
SHOW DIFFERENT SOLUTIONS BY NEXT MONDAY. BOTH INDICATE DRY WEATHER
STILL NEXT WEEKEND SO WILL CONTINUE WITH THAT FOR NOW...BUT
CONFIDENCE IS LOWERING BY SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 233 PM MDT SUN OCT 20 2013
EXPECT AREAS OF MOUNTAIN OBSCURATION OVER THE
ELKHEAD...PARK...GORE...AND PORTIONS OF THE ELK RANGES THIS
AFTERNOON. THERE IS A SLIGHT CHANCE THAT KCAG...KEEO...
KHDN...KSBS...AND KEGE WILL EXPERIENCE BRIEF MVFR CIGS IN LIGHT
SHOWERS THROUGH 03Z THEN VFR CONDITIONS WILL DOMINATE.
ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24
HOURS AND BEYOND.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JOE
LONG TERM...JAD
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1111 AM MDT SUN OCT 20 2013
.UPDATE...
ISSUED AT 1110 AM MDT SUN OCT 20 2013
SNOW SHOWERS HAVE WORKED INTO NW COLORADO THIS EARLY MORNING.
SPOTTERS BETWEEN STEAMBOAT SPRINGS AND CLARK REPORT SNOW
FLURRIES. SNOTEL SITES HAVE NOT RESPONDED YET AND ARE HOVERING
NEAR 32 DEGREES. THE MORNING MODELS ARE CONSISTENT WITH PREVIOUS
RUNS PRODUCING 1-3 INCHES IN THE ELKHEAD AND ZIRKEL MOUNTAINS WITH
LESS INTO THE PARK AND FLATTOPS MOUNTAINS...WITH SOME LIGHT SNOW
INTO THE ELK MTNS THROUGH THE AFTERNOON INCLUDING INDEPENDENCE AND
COTTONWOOD PASSES. CRAIG MAY SEE A FLURRY...AND PUT A SLIGHT
CHANCE OF SHOWERS IN THE I-70 CORRIDOR EAST OF GLENWOOD SPRINGS.
THE BEST FORCING PASSES OVER THE ELKHEADS THIS AFTERNOON BUT COLD
ADVECTIVE NW FLOW MAY PRODUCE LIGHT SNOW ACROSS THE MENTIONED
NORTHERN CO MTNS THROUGH THE EVENING HOURS WHEN THE -22C COLD CORE
PASSES. SOME CLOUDS WILL LINGER OVERNIGHT IN NW CO... OTHERWISE
CLEARING SKIES WILL KEEP TEMPERATURES BELOW NORMAL TONIGHT AND
MONDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 331 AM MDT SUN OCT 20 2013
A FAST MOVING SHORTWAVE IN THE NORTHWESTERLIES WILL IMPACT THE
NORTHERN AND PORTIONS OF THE CENTRAL MOUNTAINS TODAY. HIGH
CLOUDS AHEAD OF THE SYSTEM BEGAN SWEEPING OVER THE NORTH LAST
EVENING. EXPECT SHOWERS WILL HOLD OFF UNTIL AFTER 12Z PER
CONSENSUS OF GFS40...NAM12...RAP13...AND HRRR MODELS. THEREFORE
...PARED BACK POPS EARLY THIS MORNING.
AS THE SHORTWAVE SWEEPS SOUTHEASTWARD ACROSS SOUTHWEST WYOMING
SHOWERS WILL DEVELOP OVER THE ELKHEADS AROUND SUNRISE. THIS
ACTIVITY WILL SPREAD TO THE PARK AND GORE RANGES...FLAT TOPS...AND
ELK MOUNTAINS AS THE AXIS OF THE SHORTWAVE SWEEPS INTO NORTHWEST
COLORADO THIS AFTERNOON. UPWARD FORCING...OROGRAPHIC LIFT AND
SUFFICIENTLY STEEP LAPSE RATES WILL BRING ACCUMULATING SNOW TO
THE NORTHERN AND CENTRAL MOUNTAINS. SNOW LEVELS WILL SETTLE AROUND
MOUNTAIN BASES IN THE NORTH AND NEAR 8500 FEET IN THE CENTRAL
MOUNTAINS THIS AFTERNOON. MOISTURE LACKING WITH THIS SYSTEM SO
WILL CONTINUE WITH 1 TO 2 INCH ACCUMULATIONS IN THE MOUNTAIN AREAS
MENTIONED PREVIOUSLY. LOWER ELEVATIONS EAST OF KCAG-KASE LINE
COULD SEE BRIEF SHOWERS BUT CHANCES NOT GREAT GIVEN LIMITED
MOISTURE.
ELSEWHERE...EXPECT DRY WEATHER TO CONTINUE WITH PARTLY SUNNY TO
MOSTLY SUNNY SKIES AND HIGHS CONTINUING TO RUN A BIT COOL FOR THIS
TIME OF YEAR. A PUSH OF COOLER AIR COMBINED WITH CLOUDS AND
SHOWERS WILL DECREASE TEMPERATURES AROUND 5 DEGREES ACROSS NORTH-
CENTRAL COLORADO THIS AFTERNOON.
SNOW GRADUALLY TAPERS OFF OVERNIGHT FROM THE NORTH AS THE BULK OF
PRECIPITATION HANGS OVER THE DIVIDE THROUGH THE MORNING HOURS
MONDAY WITH FAVORABLE WIND DIRECTION FOR LINGERING LIGHT SNOW
STRETCHING ALONG THE CENTRAL MOUNTAIN CORRIDOR. SNOW LEVEL WILL
DECREASE TO AROUND 6500 FEET BY EARLY MONDAY MORNING WITH THE
ADVECTION OF COLD NORTHERLY AIR. 1 TO 3 INCHES OF SNOW IS EXPECTED
OVER THE NORTHERN MOUNTAINS AND PORTIONS OF THE CENTRAL MOUNTAINS
THROUGH EARLY MONDAY MORNING...WITH THE POTENTIAL FOR LOCALLY
HIGHER AMOUNTS. THE SHORTWAVE IS FORECAST TO PROGRESS TO THE VERY
EASTERN PART OF CENTRAL COLORADO BY NOON MONDAY...SO ALL
PRECIPITATION IS EXPECTED TO HAVE CEASED OVER THE DIVIDE WITH
BRISK NORTHERLY AIR FILTERING IN BEHIND IN AN AREA OF SUBSIDENCE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 AM MDT SUN OCT 20 2013
CLEAR SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WILL REIGN AS
HIGH PRESSURE BUILDS INTO THE REGION MONDAY NIGHT. WINDS WILL
REMAIN LIGHT...ALLOWING INVERSIONS TO DEVELOP IN VALLEY BOTTOMS
OVERNIGHT AND KEEP LOW TEMPERATURES BELOW NORMAL.
A WEAK MID-LEVEL LOW PRESSURE TROUGH OVER THE WEST COAST UNDERCUTS
THE RIDGE...MOVING EASTWARD ACROSS THE GREAT BASIN AND DESERT
SOUTHWEST TUESDAY NIGHT THROUGH THURSDAY. MODELS TAKE THE BULK OF
THE ENERGY ASSOCIATED WITH THIS FEATURE SOUTH OF THE FORECAST AREA
FROM THURSDAY NIGHT INTO FRIDAY BEFORE PUSHING IT ONTO THE
SOUTHERN PLAINS SATURDAY. LATEST ECMWF FARTHER SOUTH WITH THIS
FEATURE THAN YESTERDAY/S 00Z RUN WHICH LIMITS CHANCES FOR ANY
SENSIBLE WEATHER OVER THE SAN JUANS FRIDAY. LESS ENERGETIC GFS
SHOWED LITTLE CHANGE AND ALSO DRY FRIDAY. AS A RESULT...KEPT
MENTION OF PRECIPITATION CHANCES OUT OF THE FORECAST THROUGHOUT
THE ENTIRE EXTENDED PERIOD. EXPECT TEMPERATURES WILL HOVER NEAR
NORMAL THROUGH THE COMING WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1110 AM MDT SUN OCT 20 2013
IN NW FLOW ALOFT A WEAK PASSING DISTURBANCE WILL BRUSH NORTH-
CENTRAL COLORADO THROUGH THIS AFTERNOON AND THIS EVENING. SNOW HAS
DEVELOPED EAST OF A LINE FROM KCAG SE TO KASE AND WILL INCREASE IN
INTENSITY THIS AFTERNOON. EXPECT AREAS OF MOUNTAIN OBSCURATION
OVER THE ELKHEAD...PARK...GORE...AND PORTIONS OF THE ELK RANGES
THIS AFTERNOON. THERE IS A SLIGHT CHANCE THAT KCAG...KEEO...
KHDN...KSBS...AND KEGE WILL EXPERIENCE BRIEF MVFR CIGS IN LIGHT
SHOWERS THROUGH 06Z. ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST
THROUGH THE NEXT 24 HOURS AND BEYOND.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...NL/JAM
LONG TERM...JAM/NL
AVIATION...NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
331 AM MDT SUN OCT 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 331 AM MDT SUN OCT 20 2013
A FAST MOVING SHORTWAVE IN THE NORTHWESTERLIES WILL IMPACT THE
NORTHERN AND PORTIONS OF THE CENTRAL MOUNTAINS TODAY. HIGH
CLOUDS AHEAD OF THE SYSTEM BEGAN SWEEPING OVER THE NORTH LAST
EVENING. EXPECT SHOWERS WILL HOLD OFF UNTIL AFTER 12Z PER
CONSENSUS OF GFS40...NAM12...RAP13...AND HRRR MODELS. THEREFORE
...PARED BACK POPS EARLY THIS MORNING.
AS THE SHORTWAVE SWEEPS SOUTHEASTWARD ACROSS SOUTHWEST WYOMING
SHOWERS WILL DEVELOP OVER THE ELKHEADS AROUND SUNRISE. THIS
ACTIVITY WILL SPREAD TO THE PARK AND GORE RANGES...FLAT TOPS...AND
ELK MOUNTAINS AS THE AXIS OF THE SHORTWAVE SWEEPS INTO NORTHWEST
COLORADO THIS AFTERNOON. UPWARD FORCING...OROGRAPHIC LIFT AND
SUFFICIENTLY STEEP LAPSE RATES WILL BRING ACCUMULATING SNOW TO
THE NORTHERN AND CENTRAL MOUNTAINS. SNOW LEVELS WILL SETTLE AROUND
MOUNTAIN BASES IN THE NORTH AND NEAR 8500 FEET IN THE CENTRAL
MOUNTAINS THIS AFTERNOON. MOISTURE LACKING WITH THIS SYSTEM SO
WILL CONTINUE WITH 1 TO 2 INCH ACCUMULATIONS IN THE MOUNTAIN AREAS
MENTIONED PREVIOUSLY. LOWER ELEVATIONS EAST OF KCAG-KASE LINE
COULD SEE BRIEF SHOWERS BUT CHANCES NOT GREAT GIVEN LIMITED
MOISTURE.
ELSEWHERE...EXPECT DRY WEATHER TO CONTINUE WITH PARTLY SUNNY TO
MOSTLY SUNNY SKIES AND HIGHS CONTINUING TO RUN A BIT COOL FOR THIS
TIME OF YEAR. A PUSH OF COOLER AIR COMBINED WITH CLOUDS AND
SHOWERS WILL DECREASE TEMPERATURES AROUND 5 DEGREES ACROSS NORTH-
CENTRAL COLORADO THIS AFTERNOON.
SNOW GRADUALLY TAPERS OFF OVERNIGHT FROM THE NORTH AS THE BULK OF
PRECIPITATION HANGS OVER THE DIVIDE THROUGH THE MORNING HOURS
MONDAY WITH FAVORABLE WIND DIRECTION FOR LINGERING LIGHT SNOW
STRETCHING ALONG THE CENTRAL MOUNTAIN CORRIDOR. SNOW LEVEL WILL
DECREASE TO AROUND 6500 FEET BY EARLY MONDAY MORNING WITH THE
ADVECTION OF COLD NORTHERLY AIR. 1 TO 3 INCHES OF SNOW IS EXPECTED
OVER THE NORTHERN MOUNTAINS AND PORTIONS OF THE CENTRAL MOUNTAINS
THROUGH EARLY MONDAY MORNING...WITH THE POTENTIAL FOR LOCALLY
HIGHER AMOUNTS. THE SHORTWAVE IS FORECAST TO PROGRESS TO THE VERY
EASTERN PART OF CENTRAL COLORADO BY NOON MONDAY...SO ALL
PRECIPITATION IS EXPECTED TO HAVE CEASED OVER THE DIVIDE WITH
BRISK NORTHERLY AIR FILTERING IN BEHIND IN AN AREA OF SUBSIDENCE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 AM MDT SUN OCT 20 2013
CLEAR SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WILL REIGN AS
HIGH PRESSURE BUILDS INTO THE REGION MONDAY NIGHT. WINDS WILL
REMAIN LIGHT...ALLOWING INVERSIONS TO DEVELOP IN VALLEY BOTTOMS
OVERNIGHT AND KEEP LOW TEMPERATURES BELOW NORMAL.
A WEAK MID-LEVEL LOW PRESSURE TROUGH OVER THE WEST COAST UNDERCUTS
THE RIDGE...MOVING EASTWARD ACROSS THE GREAT BASIN AND DESERT
SOUTHWEST TUESDAY NIGHT THROUGH THURSDAY. MODELS TAKE THE BULK OF
THE ENERGY ASSOCIATED WITH THIS FEATURE SOUTH OF THE FORECAST AREA
FROM THURSDAY NIGHT INTO FRIDAY BEFORE PUSHING IT ONTO THE
SOUTHERN PLAINS SATURDAY. LATEST ECMWF FARTHER SOUTH WITH THIS
FEATURE THAN YESTERDAY/S 00Z RUN WHICH LIMITS CHANCES FOR ANY
SENSIBLE WEATHER OVER THE SAN JUANS FRIDAY. LESS ENERGETIC GFS
SHOWED LITTLE CHANGE AND ALSO DRY FRIDAY. AS A RESULT...KEPT
MENTION OF PRECIPITATION CHANCES OUT OF THE FORECAST THROUGHOUT
THE ENTIRE EXTENDED PERIOD. EXPECT TEMPERATURES WILL HOVER NEAR
NORMAL THROUGH THE COMING WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 331 AM MDT SUN OCT 20 2013
A SOUTHEASTWARD PROPAGATING UPPER LEVEL DISTURBANCE WILL BRUSH
NORTH-CENTRAL COLORADO TODAY. SNOW WILL DEVELOP OVER THE ELKHEAD
MOUNTAINS THIS MORNING THEN SPREADS SOUTHEAST WHILE INCREASING IN
INTENSITY THIS AFTERNOON. AS A RESULT...EXPECT AREAS OF MOUNTAIN
OBSCURATION OVER THE ELKHEAD...PARK...AND PORTIONS OF THE PARK
RANGE THIS MORNING...BECOMING WIDESPREAD THIS AFTERNOON. THERE IS
A SLIGHT CHANCE THAT KCAG...KEEO...KHDN...KSBS...AND KEGE WILL
EXPERIENCE BRIEF MVFR CIGS IN LIGHT SHOWERS FROM 18Z TO 00Z.
ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24
HOURS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...NL/JAM
LONG TERM...JAM/NL
AVIATION...NL
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
755 PM EDT MON OCT 21 2013
.UPDATE (TONIGHT AND TUESDAY)...
22/00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN EXPANSIVE LONGWAVE
TROUGH COVERING MUCH OF THE CONUS TO THE EAST OF THE CONTINENTAL
DIVIDE. THIS TROUGH IS ANCHORED BY A LARGE CLOSED LOW FEATURES
SPINNING OVER THE NORTHERN GREAT LAKES/SOUTHERN ONTARIO. OTHER
FEATURE OF NOTE WITHIN THIS BROAD TROUGH IS SHORTWAVE ENERGY
DROPPING SOUTHEASTWARD OVER THE CENTRAL AND SOUTHERN PLAINS AND
ADVERTISED ON WV IMAGERY BY PRONOUNCED MID/UPPER LEVEL
DRYING/SUBSIDENCE IN ITS WAKE. IT IS THIS PIECE OF SHORTWAVE ENERGY
THAT WILL EVENTUALLY HAVE SIGNIFICANT INFLUENCE ON OUR WEATHER AS IT
PASSAGE TO OUR NORTH PROPELS A WELL-DEFINED COLD FRONT ACROSS THE
FLORIDA PENINSULA DURING WEDNESDAY AND WED NIGHT. FOR NOW...THE
FORECAST AREA REMAINS WITHIN THE TRANSITION ZONE BETWEEN THE MAIN
LONGWAVE TROUGH AND UPPER RIDGING TO OUR SOUTH.
AT THE SURFACE...STILL LOOKING AT A VERY WEAK REGIONAL PRESSURE
GRADIENT DUE TO THE PRESENCE OF A WEAK AND DECAYING FRONTAL
BOUNDARY. THIS BOUNDARY HAS MOVED LITTLE IN THE PAST 24 HOURS...WITH
ITS ILL-DEFINED SIGNATURE HOLDING SOMEWHERE NEAR THE I-4 CORRIDOR.
SIMILAR TO PREVIOUS DAYS...SEEING A SCATTERING OF INLAND SHOWERS AND
STORMS WITHIN THE CONVERGENCE ZONE OF THE EAST COAST AND WEST COAST
SEA-BREEZES. EXPECT FOR UP OVER THE NATURE COAST...ALL OF THIS
ACTIVITY IS WELL INLAND FROM THE I-75 CORRIDOR. HOWEVER...CAN SEE A
BOUNDARY ON REGIONAL RADARS TRYING TO MAKE ITS WAY BACK WESTWARD
INTO SUMTER/POLK COUNTIES. WILL HAVE TO WATCH THE PROGRESS OF THIS
BOUNDARY...AS ENOUGH WESTWARD MOVEMENT BEFORE THE COMPLETE LOSS OF
DAYTIME INSTABILITY COULD SUPPORT AN ISOLATED SHOWER OR TWO BACK
INTO WESTERN HERNANDO/PASCO/HILLSBOROUGH COUNTIES LATER THIS
EVENING. EITHER WAY...AFTER 04-05Z...ALL THIS ACTIVITY SHOULD
DIMINISH AND LEAVE A GENERALLY DRY OVERNIGHT PERIOD.
TUESDAY/WEDNESDAY...
STARTING AROUND SUNRISE AND CONTINUING THROUGH THE DAY...THE
APPROACH AND AMPLIFICATION OF THE UPPER TROUGH INTO THE EASTERN
UNITED STATES WILL BOTH BEGIN TO SPREAD BROAD SYNOPTIC SUPPORT/DEEP
LAYER QG FORCING FOR ASCENT INTO THE NORTHERN HALF OF THE AREA...BUT
ALSO INCREASING UPPER DIVERGENCE WITHIN THE RRQ OF A STRENGTHENING
140+ KNOT UPPER JET. THE FORECAST FOR TUESDAY THEREFORE BECOMES A
BIT MORE COMPLEX...WITH LARGE SCALE SYNOPTIC FORCING THE DOMINANT
PLAYER TO THE NORTH OF THE I-4 CORRIDOR...AND MESOSCALE
SEA-BREEZE/INSTABILITY FACTORS THE DOMINANT DRIVING FORCES ALONG AND
SOUTH OF I-4. THE SYNOPTIC INFLUENCES SUGGEST THE HIGHER
POPS/RAINFALL COVERAGE DURING THE COURSE OF THE DAY OVER THE FAR
NORTH...WHERE LIKELY RAIN CHANCES ARE FORECAST. OVER CENTRAL AND
SOUTHERN ZONES...THE FORECAST WILL BE SIMILAR TO PREVIOUS DAYS WITH
A SCATTERING OF MAINLY LATE DAY AND INLAND SHOWERS.
THEREAFTER ON WEDNESDAY...THE CLOSER APPROACH AND PASSAGE OF THE
SHORTWAVE AXIS...AND ARRIVAL OF THE COLD FRONT...WILL SPREAD BROAD
SYNOPTIC SUPPORT FURTHER SOUTH AND PROVIDE A CHANCE FOR A PERIOD OF
ORGANIZED SHOWERS/STORMS FOR OUR CENTRAL AND SOUTHERN ZONES. HAVE A
GOOD EVENING EVERYONE!
&&
.AVIATION...
LIMITED AFTERNOON CONVECTION NOW DECAYING WELL EAST OF TERMINALS.
EXPECT MVFR FROM LATE NIGHT TO AFTER SUNRISE...WITH LCL IFR POSSIBLE
AT LAL AND PGD. LOW CIGS WILL GENERALLY DOMINATE WITH BR/FG PLAYING
A SECONDARY PART. A FEW SHRA MAY DRIFT ONSHORE EARLY AFTERNOON...
NORTH...OR LATE MORNING SOUTH AND MOVE EAST IN A SEA BREEZE. LAL IS
AN EXCEPTION AND COULD SEE TSRA.
&&
.MARINE...
A WEAK PRESSURE PATTERN WILL REMAIN IN PLACE THROUGH TUESDAY...
WITH FLOW DOMINATED BY THE AFTERNOON SEA BREEZE AND OVERNIGHT LAND
BREEZE. A STRONG COLD FRONT WILL THEN MOVE THROUGH THE WATERS
WEDNESDAY AND WEDNESDAY EVENING...WITH HIGH PRESSURE BUILDING IN
FROM THE NORTH FOR THE END OF THE WORK WEEK. WINDS AND SEAS WILL
REMAIN BELOW HEADLINE THRESHOLDS THROUGH TUESDAY NIGHT...BUT ARE
LIKELY TO REACH EXERCISE CAUTION OR ADVISORY LEVELS BY LATER
WEDNESDAY THROUGH FRIDAY IN THE WAKE OF THE STRONG COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 86 75 82 / 10 30 50 50
FMY 73 88 75 84 / 10 20 40 50
GIF 72 88 72 79 / 20 40 50 50
SRQ 73 86 75 82 / 10 20 50 50
BKV 69 86 71 79 / 10 50 50 40
SPG 77 87 76 81 / 10 20 50 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1022 AM EDT SUN OCT 20 2013
.UPDATE...
DO NOT PLAN ANY CHANGES TO MORNING UPDATES WITH THE 12Z MFL
SOUNDING INDICATING SUBSIDENCE CAP STILL IN PLACE WITH A STABLE
LAYER BETWEEN 800 AND 650 MB. ATMOSPHERE ALSO REMAINS QUITE DRY
WITH PWAT AT AROUND 1.5 INCHES. THE LOWER LAYERS HAVE MOISTENED UP
WITH DEW POINTS BACK INTO THE LOWER AND MID 70S SO CU FIELD
ALREADY FORMING AND COULD HAVE SOME EARLY ONSET OF LOW TOPPED
SHOWERS AND IF ANY CAN OVERCOME THE CAP, THEN A THUNDERSTORM
CANNOT BE RULED OUT WITH QUITE A BIT OF LIGHTNING LATE YESTERDAY
OVER WESTERN PALM BEACH COUNTY. THE HRRR DOES SHOW THIS TREND WITH
LATE AFTERNOON CONVECTION OVER THE SAME AREA. WILL WAIT FOR
EARLIER THIS AFTERNOON, BUT MAY NEED TO EXPAND THE CHANCE POP
COVERAGE A LITTLER FARTHER TO THE EAST BUT NOTHING MORE DRASTIC
THAN THAT PLANNED AT THIS TIME.
KOB
&&
.PREV DISCUSSION... /ISSUED 657 AM EDT SUN OCT 20 2013/
AVIATION...
A WEAK, DIFFUSE BOUNDARY ACROSS THE FLORIDA PENINSULA HAS BEEN A
FOCAL POINT FOR SOME ISOLATED TO SCATTERED SHOWERS. THIS BOUNDARY
WILL CONTINUE TO AFFECT THE WEATHER TODAY, WITH A CHANCE OF
SHOWERS, MAINLY IN THE LAKE REGION OF SOUTH FLORIDA, WHICH SHOULD
NOT IMPACT ANY TAF SITES. HOWEVER, THERE IS A VERY LOW POSSIBILITY
THAT A BRIEF CONVECTIVE CELL COULD IMPACT ANY GIVEN TAF SITE.
OTHERWISE, VFR CONDITIONS ARE EXPECTED. ALSO, BEING SOUTH OF THE
BOUNDARY WILL KEEP WINDS GENERALLY SOUTHERLY TODAY, PICKING UP TO
5 TO 10 KTS. THEY WILL GO LIGHT AND VARIABLE AGAIN TONIGHT.
PREV DISCUSSION... /ISSUED 358 AM EDT SUN OCT 20 2013/
DISCUSSION...
A WEAK SURFACE TROUGH JUST WEST OF THE FLORIDA KEYS CONTINUES TO
GENERATE A FEW SHOWERS WEST AND SOUTH OF KEY WEST EARLY THIS
MORNING. THIS TROUGH IS EXPECTED TO LINGER THROUGH THE DAY AND ACT
AS A FOCUS FOR ADDITIONAL SHOWERS MAINLY ACROSS THE GULF WATERS.
FOR SOUTH FLORIDA...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL
AGAIN BE POSSIBLE THROUGH THE AFTERNOON HOURS. SOUTHWEST FLOW
ALOFT WILL CONTINUE TO FUNNEL LOW LEVEL MOISTURE INTO THE AREA.
THIS COMBINED WITH WEAK SEA BREEZE INTERACTIONS SHOULD BE ENOUGH
TO SPARK A FEW SHOWERS AND STORMS MAINLY ACROSS THE INTERIOR.
FOR MONDAY INTO TUESDAY...UPPER RIDGING ENTRENCHED ACROSS THE
FLORIDA PENINSULA WILL SLOWLY BEGIN TO BREAK DOWN AS A BROAD H5
SHORTWAVE BEGINS TO SWING DOWN THROUGH THE MIDSOUTH STATES. SLIGHT
CHANCES FOR AFTERNOON SHOWERS AND A FEW THUNDERSTORMS WILL BE
PREVALENT EACH DAY AS A SLIGHTLY DEEPER MOISTURE AXIS PUSHES INTO
SOUTH FLORIDA AHEAD OF AN APPROACHING COLD FRONT.
THE COLD FRONT IS STILL EXPECTED TO PUSH INTO THE SOUTH FLORIDA
AREA BY WEDNESDAY. MODELS TEND TO BE IN GOOD AGREEMENT ON THE
TIMING OF THE FRONTAL PASSAGE. NORTH TO NORTHEASTERLY SURFACE FLOW
WILL THEN PREVAIL AND INCREASE THROUGH THE END OF THE WEEK DUE TO
A RATHER TIGHT PRESSURE GRADIENT BETWEEN LOWER PRESSURE TO THE
SOUTH AND STRONG HIGH PRESSURE ACROSS THE SOUTHEAST STATES. THIS
WILL ALLOW NOTICEABLY MILDER TEMPERATURES TO FILTER ACROSS THE AREA
THURSDAY INTO NEXT WEEKEND. WOULD NOT BE SURPRISED TO SEE MORNING
LOWS IN THE 50S ACROSS INTERIOR AREAS FRIDAY MORNING.
THE SOUTHWARD EXTENT OF THE DRY AIR PUSH IN THE WAKE OF THE FRONTAL
PASSAGE IS UNCLEAR AT THIS TIME. BOTH THE GFS AND ECMWF SEEM TO
KEEP AN OVERRUNNING MOISTURE AXIS JUST SOUTH OF THE AREA ACROSS THE
FLORIDA STRAITS. ANY FLUCTUATION OVER THE NEXT FEW DAYS WOULD
GREATLY INFLUENCE RAIN CHANCES TOWARD THE END OF THE WEEK.
SUBSEQUENT MODEL RUNS WILL NEED TO BE MONITORED CLOSELY FOR
CONSISTENCY.
MARINE...
TRANQUIL MARINE CONDITIONS WILL CONTINUE INTO EARLY NEXT WEEK WITH
A PREVAILING E-SE WIND AT 10 KNOTS OR LESS WITH CORRESPONDING SEAS
AT 3 FEET OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 75 88 74 / 20 10 20 20
FORT LAUDERDALE 88 78 88 77 / 20 20 20 20
MIAMI 87 77 88 76 / 20 20 20 20
NAPLES 88 74 87 72 / 20 10 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1039 PM EDT MON OCT 21 2013
.UPDATE...
ADJUSTED SLIGHT POPS ONCE AGAIN FARTHER NORTH THROUGH TONIGHT ACROSS
MUCH OF CENTRAL GEORGIA BASED ON COMBINATION OF PROGGED WEAK VORT
MAX LOCATION AND GENERAL CONSENSUS OF MODEL PRECIP...THOUGH A FEW
OUTLIERS INDICATING POTENTIAL ACROSS NORTH GEORGIA AS WELL. NOT
BUYING INTO THIS RIGHT NOW...THOUGH RECENT HISTORY IN A SIMILAR
SYSTEM PROVED OTHERWISE. WILL CONTINUE TO UPDATE AS
NECESSARY...THOUGH ANY RAIN TOTALS ARE EXPECTED TO BE LIGHT.
LATEST NAM CONDENSATION PRESSURE DEFICITS ARE A BIT LOWER AND MORE
EXPANSIVE THAN EARLIER SO HAVE EXPANDED SOUTHEASTERN FOG
POTENTIAL. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 813 PM EDT MON OCT 21 2013/
PREV DISCUSSION... /ISSUED 232 PM EDT MON OCT 21 2013/
.QUICK SHOT OF RAIN TUESDAY BEFORE COLDER AIR ARRIVES...
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST STATES SHOWS HIGH
PRESSURE RIDGE REMAINS IN CONTROL BUT INFLUENCE IS WEAKENING. THIS
IS DUE TO THE APPROACH OF AN UPPER LEVEL TROUGH WHICH RUC ANALYSIS
HAS SITUATED FROM EASTERN ILLINOIS THROUGH MISSOURI AND KANSAS AS
WELL AS ADDITIONAL RIPPLES OF UPPER LEVEL ENERGY CLOSER TO HOME
EMBEDDED IN BROADER TROUGH REGIME. AS FAR AS THE SENSIBLE WEATHER
THIS HAS PRODUCED AT THE SURFACE...PRETTY MUCH A MIXED BAG WITH
LOW CLOUDS IN VICINITY OF RIDGE AXIS AROUND ATHENS JUST STARTING
TO BREAK UP AND A MOSTLY SUNNY DAY ELSEWHERE WHICH IS QUICKLY
GIVING WAY TO INCREASED CIRRUS IN SW FLOW ALOFT. SOME LIGHT
RETURNS FORM THIS ON RADAR FOR SOUTHERN SECTIONS BUT NO EVIDENCE
ANY OF THIS IS REACHING THE GROUND JUST YET.
FOR TONIGHT...GULF COAST WAVE AT THE UPPER LEVELS WILL MOVE INTO
SOUTH GEORGIA THIS EVENING ALLOWING FOR INCREASED LIFT AND
MOISTURE BOTH AT THE MID LEVELS AND EVENTUALLY LOW LEVELS BY
DAYBREAK. IN FACT...MODELS INDICATE LOW CLOUDS REDEVELOPING ACROSS
THE SE ZONES WITH SOME POTENTIAL FOR REDUCED VSBY AS WELL PRIOR TO
DAYBREAK. EXPECT THICKENING CLOUD DECK AND AFOREMENTIONED LIFT TO
RESULT IN -RA WITH LOW END CHANCE ADVERTISED FOR NOW. THIS MAY
PROVE TO BE TOO LOW GIVEN THE AMOUNT OF OMEGA INDICATED BY THE
MODELS BUT HAVE AT LEAST RAMPED UP SOME 10 TO 20 PERCENT ABOVE
GUIDANCE.
SAME HOLDS TRUE FOR TUESDAY AS GUIDANCE POPS LOOK MUCH TOO LOW FOR
THE AMOUNT OF MOISTURE AND LIFT INDICATED BY THE
MODELS...ESPECIALLY THE NAM12. SETUP LOOKS AN AWFUL LOT LIKE THIS
PAST SATURDAY WHEN GUIDANCE HAD NO CLUE AND RAIN WAS MUCH MORE
WIDESPREAD THAN EXPECTED. WITH SECONDARY SHOT OF ENERGY COMING
ACROSS LATE IN THE DAY...FEEL LOW END CHANCE POPS AT LEAST ARE
WARRANTED AND THESE MAY NEED TO BE INCREASED FURTHER IF TRENDS
CONTINUE. ALSO WENT ON THE LOW SIDE OF GUIDANCE FOR TUE MAX TEMPS
BASED ON MORE PRECIP AND CLOUD COVER.
DEESE
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
VERY LITTLE CHANGES NEEDED TO THE EXTENDED FORECAST. BY WED MORNING
THE MAIN FRONTAL BOUNDARY WILL HAVE MOVED OFF THE GA/SC COAST WITH
HIGH PRESSURE BUILDING INTO THE REGION FROM THE CENTRAL PLAINS. A
COOLER AIRMASS WILL MOVE IN WITH THIS RIDGE AS WE WILL SE SOME OF
THE COOLEST TEMPS SO FAR THIS SEASON. LOW TEMPS THU MORNING EXPECTED
IN THE 30S AND 40S WITH HIGH TEMPS ONLY GETTING UP INTO THE 60S THU.
THIS COOL AIR REMAINS OVER THE REGION THROUGH THE END OF THE WEEK
AND EVEN GETS REINFORCED FRI/SAT AS ANOTHER STRONGER RIDGE MOVES IN
BEHIND A DRY COLD FRONT FROM THE NORTHERN PLAINS. SOME AREAS ACROSS
EXTREME N GA WILL SE BELOW FREEZING TEMPS SAT MORNING. TEMPS WILL
BEGIN TO REBOUND SUN/MON WILL SEE MAINLY BELOW SEASONAL NORMS WED
THROUGH SAT. NO PRECIP EXPECTED THIS WEEK.
01
&&
.AVIATION...
00Z UPDATE...
MAINLY VFR CONDITIONS EXPECTED FOR MOST SITES...WHILE MVFR VSBYS
POSSIBLE AT KAHN AND KMCN IN EARLY MORNING. ALSO POTENTIAL FOR
MVFR CIGS BUILDING INTO KMCN FOR EARLY MORNING BUT BEST CHANCE
LOOKS TO BE SOUTH AND EAST. CIGS GENERALLY NEAR 10 KFT WITH
POSSIBLE LOWERING TO NEAR 6-8 KFT AND SCATTERING OUT BY TUESDAY
EVENING AS WEAK FRONT PUSHES SOUTHEASTWARD. FORECAST PRECIP
CHANCES TOO LOW TO INCLUDE IN TAF FOR NOW BUT BEST CHANCE FOR ANY
RAIN WOULD BE IN AFTERNOON. IF THIS WERE TO OCCUR...THEN WOULD
EXPECT CIGS OF 6-8 KFT EARLIER IN AFTERNOON. WINDS MAINLY CALM
OVERNIGHT BECOMING WEST AT NEAR 7 KTS OR LESS TUESDAY...THEN
SWITCHING NW BY EVENING WITH FRONTAL PASSAGE.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON RAIN CHANCES...EARLY MORNING CIGS NEAR KMCN AND
AFTERNOON CIGS FOR ALL SITES.
HIGH CONFIDENCE ALL ELSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 54 72 50 65 / 20 30 20 0
ATLANTA 55 70 49 61 / 10 30 20 0
BLAIRSVILLE 45 67 42 54 / 5 30 20 5
CARTERSVILLE 47 70 45 59 / 10 30 10 0
COLUMBUS 59 77 54 69 / 20 20 20 0
GAINESVILLE 53 69 49 60 / 10 30 20 0
MACON 57 75 49 70 / 20 30 20 0
ROME 46 70 44 60 / 5 30 10 5
PEACHTREE CITY 50 72 49 63 / 20 20 20 0
VIDALIA 63 75 55 74 / 30 40 30 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....01
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
813 PM EDT MON OCT 21 2013
.UPDATE...
HAVE MAINLY UPDATED EVENING FORECAST TO INCLUDE SLIGHT CHANCE POPS
FOR RAIN IN THE FAR SOUTHERN TIER OF THE CWA BASED ON OBSERVED
BANDING OF UPSTREAM LOW REFLECTIVITY AND MODEL CONSENSUS IN
PRESENCE OF WEAK VORT MAX PROGGED TO TRAVERSE PORTIONS OF CENTRAL
GA OVERNIGHT. ALSO TRENDED DEWPOINTS A BIT HIGHER IN MOST AREAS
BASED ON RECENT OBS AND CONTINUED PRESENCE OF UPPER CLOUD DECK.
BEST CHANCE FOR AREAS OF FOG IN THE EARLY MORNING LOOKS TO BE
SOUTH AND EAST OF MACON BASED ON NAM CONDENSATION PRESSURE
DEFICITS. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 232 PM EDT MON OCT 21 2013/
..QUICK SHOT OF RAIN TUESDAY BEFORE COLDER AIR ARRIVES...
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST STATES SHOWS HIGH
PRESSURE RIDGE REMAINS IN CONTROL BUT INFLUENCE IS WEAKENING. THIS
IS DUE TO THE APPROACH OF AN UPPER LEVEL TROUGH WHICH RUC ANALYSIS
HAS SITUATED FROM EASTERN ILLINOIS THROUGH MISSOURI AND KANSAS AS
WELL AS ADDITIONAL RIPPLES OF UPPER LEVEL ENERGY CLOSER TO HOME
EMBEDDED IN BROADER TROUGH REGIME. AS FAR AS THE SENSIBLE WEATHER
THIS HAS PRODUCED AT THE SURFACE...PRETTY MUCH A MIXED BAG WITH
LOW CLOUDS IN VICINITY OF RIDGE AXIS AROUND ATHENS JUST STARTING
TO BREAK UP AND A MOSTLY SUNNY DAY ELSEWHERE WHICH IS QUICKLY
GIVING WAY TO INCREASED CIRRUS IN SW FLOW ALOFT. SOME LIGHT
RETURNS FORM THIS ON RADAR FOR SOUTHERN SECTIONS BUT NO EVIDENCE
ANY OF THIS IS REACHING THE GROUND JUST YET.
FOR TONIGHT...GULF COAST WAVE AT THE UPPER LEVELS WILL MOVE INTO
SOUTH GEORGIA THIS EVENING ALLOWING FOR INCREASED LIFT AND
MOISTURE BOTH AT THE MID LEVELS AND EVENTUALLY LOW LEVELS BY
DAYBREAK. IN FACT...MODELS INDICATE LOW CLOUDS REDEVELOPING ACROSS
THE SE ZONES WITH SOME POTENTIAL FOR REDUCED VSBY AS WELL PRIOR TO
DAYBREAK. EXPECT THICKENING CLOUD DECK AND AFOREMENTIONED LIFT TO
RESULT IN -RA WITH LOW END CHANCE ADVERTISED FOR NOW. THIS MAY
PROVE TO BE TOO LOW GIVEN THE AMOUNT OF OMEGA INDICATED BY THE
MODELS BUT HAVE AT LEAST RAMPED UP SOME 10 TO 20 PERCENT ABOVE
GUIDANCE.
SAME HOLDS TRUE FOR TUESDAY AS GUIDANCE POPS LOOK MUCH TOO LOW FOR
THE AMOUNT OF MOISTURE AND LIFT INDICATED BY THE
MODELS...ESPECIALLY THE NAM12. SETUP LOOKS AN AWFUL LOT LIKE THIS
PAST SATURDAY WHEN GUIDANCE HAD NO CLUE AND RAIN WAS MUCH MORE
WIDESPREAD THAN EXPECTED. WITH SECONDARY SHOT OF ENERGY COMING
ACROSS LATE IN THE DAY...FEEL LOW END CHANCE POPS AT LEAST ARE
WARRANTED AND THESE MAY NEED TO BE INCREASED FURTHER IF TRENDS
CONTINUE. ALSO WENT ON THE LOW SIDE OF GUIDANCE FOR TUE MAX TEMPS
BASED ON MORE PRECIP AND CLOUD COVER.
DEESE
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
VERY LITTLE CHANGES NEEDED TO THE EXTENDED FORECAST. BY WED MORNING
THE MAIN FRONTAL BOUNDARY WILL HAVE MOVED OFF THE GA/SC COAST WITH
HIGH PRESSURE BUILDING INTO THE REGION FROM THE CENTRAL PLAINS. A
COOLER AIRMASS WILL MOVE IN WITH THIS RIDGE AS WE WILL SE SOME OF
THE COOLEST TEMPS SO FAR THIS SEASON. LOW TEMPS THU MORNING EXPECTED
IN THE 30S AND 40S WITH HIGH TEMPS ONLY GETTING UP INTO THE 60S THU.
THIS COOL AIR REMAINS OVER THE REGION THROUGH THE END OF THE WEEK
AND EVEN GETS REINFORCED FRI/SAT AS ANOTHER STRONGER RIDGE MOVES IN
BEHIND A DRY COLD FRONT FROM THE NORTHERN PLAINS. SOME AREAS ACROSS
EXTREME N GA WILL SE BELOW FREEZING TEMPS SAT MORNING. TEMPS WILL
BEGIN TO REBOUND SUN/MON WILL SEE MAINLY BELOW SEASONAL NORMS WED
THROUGH SAT. NO PRECIP EXPECTED THIS WEEK.
01
&&
.AVIATION...
00Z UPDATE...
MAINLY VFR CONDITIONS EXPECTED FOR MOST SITES...WHILE MVFR VSBYS
POSSIBLE AT KAHN AND KMCN IN EARLY MORNING. ALSO POTENTIAL FOR
MVFR CIGS BUILDING INTO KMCN FOR EARLY MORNING BUT BEST CHANCE
LOOKS TO BE SOUTH AND EAST. CIGS GENERALLY NEAR 10 KFT WITH
POSSIBLE LOWERING TO NEAR 6-8 KFT AND SCATTERING OUT BY TUESDAY
EVENING AS WEAK FRONT PUSHES SOUTHEASTWARD. FORECAST PRECIP
CHANCES TOO LOW TO INCLUDE IN TAF FOR NOW BUT BEST CHANCE FOR ANY
RAIN WOULD BE IN AFTERNOON. IF THIS WERE TO OCCUR...THEN WOULD
EXPECT CIGS OF 6-8 KFT EARLIER IN AFTERNOON. WINDS MAINLY CALM
OVERNIGHT BECOMING WEST AT NEAR 7 KTS OR LESS TUESDAY...THEN
SWITCHING NW BY EVENING WITH FRONTAL PASSAGE.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON RAIN CHANCES...EARLY MORNING CIGS NEAR KMCN AND
AFTERNOON CIGS FOR ALL SITES.
HIGH CONFIDENCE ALL ELSE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 54 72 50 65 / 5 30 20 0
ATLANTA 55 70 49 61 / 5 30 20 0
BLAIRSVILLE 45 67 42 54 / 5 30 20 5
CARTERSVILLE 47 70 45 59 / 5 30 10 0
COLUMBUS 59 77 54 69 / 10 20 20 0
GAINESVILLE 53 69 49 60 / 5 30 20 0
MACON 57 75 49 70 / 10 30 20 0
ROME 46 70 44 60 / 5 30 10 5
PEACHTREE CITY 50 72 49 63 / 5 20 20 0
VIDALIA 63 75 55 74 / 30 40 30 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....01
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1219 AM CDT SUN OCT 20 2013
.DISCUSSION...
927 PM CDT
NO CHANGES TO CURRENT FROST ADVISORY.
LATEST SATELLITE/RADAR IMAGERY DEPICTING CLOUD COVER ISOLATED
LIGHT SHOWERS STILL ACROSS THE CWA...ASSOCIATED WITH UPPER LEVEL
WAVE/TROUGH AND SURFACE REFLECTION. ALTHOUGH LATEST RAP ANALYSIS
IS INDICATING SOME PERSISTENT WEAK WAA ACROSS NORTH CENTRAL
ILLINOIS...THIS SHOULD WEAKEN OVER THE NEXT SEVERAL HOURS AS
TROUGH DEPARTS TO THE EAST. CLEARING SKIES AND DIMINISHING WINDS
SHOULD ALLOW FOR TEMPS TO STILL DROP OVERNIGHT...WITH THIS ALREADY
BEING OBSERVED IN LOCATIONS THAT SAW SOME PARTIAL CLEARING EARLY
ON. SO HAVE MADE MINOR ADJUSTMENTS TO TEMPS TONIGHT WITH CURRENT
ADVISORY LOCATION STILL APPEARING TO BE ON TRACK. DESPITE THIS
BEING THE PREFERRED LOCATION FOR BETTER FROST DEVELOPMENT...PATCHY
FROST CANNOT BE RULED OUT BRIEFLY LATE TONIGHT INTO EARLY SUNDAY
MORNING FOR THE REMAINDER OF THE CWA. ALSO...LATEST DEWPOINT
TRENDS COINCIDING WITH TEMPS TONIGHT COULD ALLOW FOR PATCHY
FOG...AND HAVE ADDED TO THE GRIDS PRIMARILY FOR NORTHERN ILLINOIS.
RODRIGUEZ
//PREV DISCUSSION...
243 PM CDT
REST OF THE WEEKEND...TONIGHT THROUGH SUNDAY NIGHT...
WEATHER TO BE CONTROLLED BY THE LARGE UPPER TROUGH EXTENDING
ACROSS WESTERN HUDSON BAY SOUTHWARD TO THE OZARKS EARLY THIS
AFTERNOON MOVING TO EASTERN CANADA AND NEW ENGLAND OVERNIGHT AND
DURING SUNDAY. THIS WILL ALLOW WEAK UPPER RIDGING TO OCCUR OVER
THE GREAT LAKES AND MIDWEST SUNDAY AS THIS UPPER TROUGH ROTATES
NORTHEASTWARD AND ANOTHER UPPER TROUGH DEEPENS OVER THE UPPER
MIDWEST AND THE UPPER AND MID MS VALLEY DURING SUNDAY AND SUNDAY
NIGHT.
HAVE RETAINED MENTION OF FROST ACROSS ACROSS NORTH CENTRAL AND
NORTHEAST IL OUTSIDE OF THE METRO AREA THOUGH CONFIDENCE IS NOT
PARTICULARLY HIGH AS WARM AIR ADVECTION CLOUDS CONTINUE TO SPREAD
FROM IA ACROSS NORTHERN IL LATER THIS AFTERNOON AND TONIGHT
SHOULD BE ENOUGH BREAKS DURING THE OVERNIGHT FOR AREAS OF FROST.
A BACKING AND INCREASING LOW LEVEL FLOW DURING SUNDAY WILL ALLOW
SOME MODERATION IN TEMPERATURES AS SIGNIFICANT WARM AIR ADVECTION
OCCURS. WHILE CLOUDS ARE EXPECTED TO GRADUALLY BE ON THE INCREASE
DURING THE DAY THE WARM AIR ADVECTION ITSELF SHOULD PUSH SUNDAY
HIGH TEMPERATURES UP TO THE UPPER 50S NORTH TO MID 60S SOUTHWEST.
DESPITE THE INCREASING CLOUDINESS AS THE UPPER WAVE ROTATES
ACROSS FROM THE NORTHERN PLAINS TO OVER MN AND IA ANY REAL THREAT
OF RAIN WILL REMAIN NORTH OF THE WI BORDER WHERE THE BEST FORCING
WILL BE. AS THE UPPER TROUGH MOVES TO WESTERN WI AND NORTHWEST
AND WEST CENTRAL IL DURING SUNDAY NIGHT POPS WILL RISE TO SLIGHT
CHANCE AS THE UPPER TROUGH APPROACHES AND AN ASSOCIATED COLD
FRONT PUSHES SOUTHEASTWARD ACROSS THE LOCAL FORECAST AREA.
MONDAY THROUGH SATURDAY...
THE MODERATION IN TEMPERATURES WILL BE SHORT LIVED AS THE UPPER
FLOW STARTS TO RETURN TO STRONG NORTHWESTERLY ACROSS THE AREA BY
MONDAY NIGHT WITH A SERIES OF SHORT WAVES ROTATING THROUGH THE
UPPER TROUGH PROVIDING REINFORCING SHOTS OF VERY COOL AIR THROUGH
THE WEEK KEEPING HIGH TEMPERATURES DOWN TO MID 40S TO LOWER
50S...WITH LOWS FROM UPPER 20S TO MID 30S.
USING THE 12Z ECMWF AS A GOOD COMPROMISE BETWEEN MODEL SOLUTIONS
THE MAIN PERIODS FOR A THREAT OF PRECIPITATION ARE FROM LATER
TUESDAY INTO WEDNESDAY AS A SHORT WAVE APPROACHES AND MOVES
ACROSS THE AREA AND THEN NEXT SATURDAY AS AN UPPER TROUGH MOVES
EAST OVER THE UPPER MIDWEST AND THE MID AND LOWER MO VALLEY
REGIONS PUSHING ANOTHER COLD FRONT INTO THE LOCAL AREA DURING THE
DAY.
WITH THE TUESDAY-TUESDAY NIGHT SHORT WAVE TROUGH PASSAGE THE
COLUMN COOLS TO BELOW 0C ACROSS NORTH CENTRAL AND FAR NORTHEAST
IL DURING THURSDAY NIGHT SO ANY REMAINING RAIN MAY MIX WITH OR
CHANGE TO SNOW BEFORE ENDING.
WITH SEVERAL SHORT WAVES TO BE ROTATING THROUGH THE MEAN UPPER
TROUGH THERE COULD BE OTHER TIME-FRAMES WHEN THERE WOULD BE AT
LEAST A SLIGHT CHANCE TO LOW END CHANCE OF PRECIPITATION BUT
TIMING OF ANY ONE OF THESE SMALLER DISTURBANCES IS PRETTY MUCH
FUTILE THESE FEATURES TYPICALLY GET LOST IN THE NOISE OF THE
PROGS.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIOD OF STRONG SOUTH WINDS WITH GUSTS AROUND 25 KT THIS
AFTERNOON AND POSSIBLY INTO THIS EVE.
* SCATTERED -SHRA WITH POSSIBLE TEMPORARY MVFR CONDITIONS THIS
EVE.
* GUSTY WEST WINDS LATE SUNDAY NIGHT.
//DISCUSSION...UPDATED 06Z...
TEMPORARY RIDGING WILL PREVAIL THROUGH SUNRISE BEFORE SOUTHERLY
WINDS ENSUE. THESE WILL INCREASE IN SPEED THIS AFTERNOON AS STRONG
LOW PRESSURE DEVELOPS ACROSS THE UPPER MISSISSIPPI VALLEY. SOME
PERIODIC GUSTINESS MAY CONTINUE IN THE EVE. AS A STRONG COLD FRONT
WRAPS AROUND THIS LOW AND APPROACHES THE TAF SITES THIS
EVE...SCATTERED SHOWERS ARE ALSO POSSIBLE. IF THESE
MATERIALIZE...TEMPORARY MVFR CONDITIONS COULD EASILY ACCOMPANY
THEM. THE STRONG COLD FRONT WILL MOVE FROM WEST TO EAST ACROSS THE
TAF SITES SUNDAY NIGHT AND TURN THE WINDS WESTERLY WITH A RE-
INCREASE IN GUSTINESS. A BRIEF PERIOD OF MVFR CIGS ARE ALSO
POSSIBLE WITH THIS FEATURE.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM IN WINDS THIS AFTERNOON AND TONIGHT. HIGH CONFIDENCE THAT
WINDS WILL BE BETWEEN 160 AND 210 THIS AFTERNOON.
* LOW IN SHRA THIS EVE AND POSSIBLE MVFR CONDITIONS.
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...MVFR CIGS LIKELY.
TUESDAY...MVFR CIGS POSSIBLE. CHANCE OF -RA OR -RSSN.
WEDNESDAY...MVFR CIGS POSSIBLE...MAINLY EARLY.
THURSDAY AND FRIDAY...PROBABLY VFR.
MTF/IZZI
&&
.MARINE...
334 PM CDT
A VERY ACTIVE PERIOD ON THE WAY ACROSS THE LAKE AS A SERIES OF LOW
PRESSURE SYSTEMS AND A UNSEASONABLY COLD AIR MASS COMBINE TO BRING
STRONG WINDS MOST OF THE FORECAST PERIOD. WEST WINDS OVER THE SOUTH
HALF WILL RAMP UP TO 30 KT THIS EVENING BEFORE DIMINISHING SOME
LATE. THERE WILL BE A BRIEF PERIOD OF LIGHTER SOUTH WINDS SUNDAY
MORNING BEFORE LOW PRESSURE APPROACHES FROM THE WEST LATER SUNDAY
AND SOUTHERLY WINDS INCREASE.
SOME UNCERTAINTY EXISTS AS TO THE TRACK AND TIMING OF THE LOW...BUT
THERE IS GOOD AGREEMENT AMONGST GUIDANCE FOR SOUTH TO SOUTHWEST
WINDS UP TO GALE FORCE SOMETIME SUNDAY EVENING INTO THE OVERNIGHT
FOR THE CENTRAL AND SOUTHERN PORTION OF THE LAKE. THEREFORE HAVE
ISSUED A GALE WATCH FOR THE CENTRAL AND SOUTH STARTING AT 00Z
SUNDAY. A VERY STRONG COLD FRONT WILL SWEEP ACROSS THE LAKE AS THE
LOW LIFTS TO EASTERN LAKE SUPERIOR BY EARLY MONDAY AND DEEPENS.
SOUTHWEST GALES WILL QUICKLY TRANSITION TO WESTERLY GALES ON THE
CENTRAL AND SOUTH...WHILE WESTERLY GALES WILL DEVELOP OVER THE NORTH
TOWARD EARLY MONDAY MORNING. A WINTER LIKE AIRMASS WILL POUR ACROSS
THE LAKE...SUPPORTING EXTREMELY UNSTABLE CONDITIONS AND EFFICIENT
MIXING. WEST GALES WILL INCREASE TO 40 KT ON THE NORTH PART OF THE
LAKE ON MONDAY...WITH 35 KT CONTINUING TO THE SOUTH. THERE THEN
APPEARS TO BE ANOTHER COLD FRONT OR SECONDARY SURGE OF COLD AIR
MONDAY NIGHT EXPECTED TO KEEP GALES GOING ON THE NORTH ALL THE WAY
INTO TUESDAY MORNING. THUS HAVE EXTENDED THE GALE WATCH THERE UNTIL
15Z TUESDAY.
FOR THE NEARSHORE WATERS...HAVE EXTENDED THE SMALL CRAFT ADVISORY
FOR GARY AND POINTS EAST UNTIL 9Z SUNDAY AS WAVES WILL BE SLOWER TO
SUBSIDE. WILL THEN LIKELY NEED A SMALL CRAFT ADVISORY FOR ALL THE
NEARSHORE ZONES SOMETIME SUNDAY EVENING THROUGH MONDAY
EVENING...THEN AT LEAST A PORTION OF THE INDIANA NEARSHORE ALL THE
WAY THROUGH TUESDAY EVENING DUE TO WAVES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012 UNTIL 8 AM SUNDAY.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM
SUNDAY TO 4 AM TUESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...3 AM
MONDAY TO 10 AM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
342 PM EDT SUN OCT 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SUN OCT 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE
UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER
STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA.
290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS
SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB
TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE
SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED
INTO NW UPPER MI AND ERN LAKE SUPERIOR.
THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND
SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM
WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON
MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL
SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND
ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH
RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS
SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER
TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE
SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES
BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR
BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW
INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 342 PM EDT SUN OCT 20 2013
MON NIGHT...MODELS SHOW THE ELONGATED SFC TROUGH FM LOW JUST SOUTH
OF JAMES BAY WILL BE SITUATED OVER NRN LAKE SUPERIOR ON MONDAY. AS
THE STRONG SHORTWAVE/CLOSED MID-UPR LVL LOW FM MANITOBA BEGINS TO
MOVE ACROSS LAKE SUPERIOR AND UPPER MI MON NIGHT THIS WILL PROPEL
THE SFC TROF ACROSS WRN LAKE SUPERIOR AND WRN UPR MI MON EVENING AND
ACROSS ERN LAKE SUPERIOR AND CENTRAL/ERN UPR MI LATE MON NIGHT. THE
TIMING OF THIS TROUGH WILL BE IMPORTANT AS WINDS WILL SHIFT FM
WESTERLY TO NNW AND BRING STRONGLY CONVERGENT CYCLONIC FLOW TO FOCUS
LAKE EFFECT SHOWERS INTO WESTERN UPPER MI MON EVENING AND ACROSS THE
REST OF THE NORTH HALF UPPER MI LATE MON NIGHT. 850 MB TEMPS AROUND
-6C OVER LAKE SUPERIOR ALONG WITH DEEP MOISTURE AND STRONG CYCLONIC
FLOW WILL RESULT IN PLENTY OF LAKE ENHANCED PCPN OVER THE NORTHERN
HALF OF THE UPPER MI MON NIGHT INTO TUE MORNING. MODEL SOUNDINGS
INDICATE THERE SHOULD BE ENOUGH LOW LEVEL COLD AIR FOR AT LEAST
SEVERAL INCHES OF WET ACCUMULATING SNOW OVER THE HIGHER TERRAIN OF
WEST HALF OF UPPER MI...ESPECIALLY WHERE UPSLOPE NW TO NNW FLOW
PREVAILS. CONFIDENCE IN SNOW AMOUNTS IS STILL ONLY AVERAGE GIVEN THE
MODEL DIFFERENCES WITH TIMING OF THE TROUGH AND SHIFT OF LOW LEVEL
WINDS. THE BEST CHANCE FOR SIGNIFICANT SNOW ACCUMULATIONS WILL BE
OVER THE HIGHER TERRAIN OF THE WEST FROM NEAR IRONWOOD TROUGH
ROCKLAND TO TWIN LAKES AND MOHAWK AND OVER THE HURON MOUNTAINS OF
BARAGA AND MARQUETTE COUNTIES. SOME ACCUMULATING SNOW WILL ALSO BE
LIKELY FROM THE HURON MOUNTAINS TO NEGAUNEE MON NIGHT.
AT THIS POINT...IT APPEARS THAT SNOW ACCUMULATION WILL STAY BELOW
WARNING CRITERIA FOR TWO MAIN REASONS. ONE...MODEL SNDGS SUGGEST THE
BEST DENDRITIC SNOW GROWTH LAYER WILL BE ABOVE THE BEST MODEL
OMEGA/LIFT WITH SYSTEM WHICH WILL LIKELY LIMIT SNOW/WATER RATIOS TO
AROUND 8/1. TWO...MODEL DEEP LAYER Q-VECT CONV INDICATES THAT THE
BEST ENHANCEMENT/SYNOPTIC SCALE FORCING FOR LAKE SNOW SHOWERS WILL
BE BEFORE THE PASSAGE OF THE TROUGH OR BEFORE THE WINDS SHIFT FROM W
TO NNW. I DON`T DOUBT THAT THERE COULD BE A QUICK INCH OR TWO OF
SNOW WITH GOOD CONVERGENCE AND A BAND OF HEAVIER SNOW RIGHT ALONG
THE TROUGH PASSAGE. BUT AFTER THE TROUGH PASSAGE...PURE LAKE EFFECT
WILL TAKE OVER...AND GIVEN THAT 850 MB TEMPS FALL AT BEST TO -7C
OVER WRN LAKE SUPERIOR EQUATING TO A LAKE DELTA-T OF 16C...WOULD
EXPECT NO MORE THAN UP TO 3 INCHES OF ADDITIONAL ACCUMULATION AT
BEST THROUGH TUE MORNING OVER FAVORED HIGHER TERRAIN LOCATIONS. FOR
THIS REASON WILL NOT ISSUE A WATCH BUT WILL CONTINUE TO HIGHLIGHT
SNOW ACCUMULATION IN A SPS.
TUE-FRI...WITH THE MEAN LONG WAVE TROUGH REMAINING OVER THE GREAT
LAKES AND ERN CONUS...NW FLOW AND A SERIES OF WEAK CLIPPER SHRTWVS
ARE EXPECTED TO MOVE THROUGH THE UPPER LAKES. THIS WILL BRING
PERIODS OF SNOW SHOWERS...MIXED WITH RAIN AT TIMES...THAT WILL BE
ENHANCED BY LAKE SUPERIOR AS 850 MB TEMPS CONTINUE TO FALL INTO THE
-8C TO -10C RANGE. LOCATIONS GENERALLY FAVORED BY NW FLOW WILL SEE
BEST CHANCE FOR PCPN. SOME ADDITIONAL ACCUMULATING SNOW IS POSSIBLE
AND AS IS TYPICAL IN EARLY SEASON LAKE EFFECT REGIMES...GRAUPEL WILL
LIKELY ALSO BE MIXED WITH ANY RAIN/SNOW SHOWERS. LAKE EFFECT PCPN
WILL DIMINISH BY FRIDAY AS UPPER TROUGH MOVES EAST AND RIDGING
BUILDS IN FM THE WEST.
NEXT WEEKEND...MODELS SHOW PLENTY OF VARIABILITY OUT TO DAYS 6 AND 7
OF THE FCST. ALL MODELS SHOW ANOTHER CLIPPER SHORTWAVE ROUNDING THE
WRN CONUS RIDGE AND DIVING INTO THE NRN PLAINS AND UPPER GREAT LAKES
REGION BUT TRACK AND TIMING OF SHORTWAVE IS UNCERTAIN AT THIS TIME.
FOR NOW WILL GO WITH A GENERAL CONSENSUS FCST AND INCLUDE CHC POPS
FOR RAIN/SNOW SHOWERS AND TEMPS REMAINING BLO NORMAL FOR NEXT
SAT-SUN. THE 00Z ECMWF ADVERTISES YET ANOTHER CLIPPER SHORTWAVE
MOVING IN FOR THE EARLY PART OF THE FOLLOWING WORK WEEK WHICH WOULD
USHER IN THE COLDEST AIRMASS YET OF THE SEASON WITH 850 MB TEMPS
FALLING AOB -12C. IF THIS SOLUTION HOLDS TRUE...THE LAST FEW DAYS OF
OCTOBER WILL FEATURE CONTINUED BELOW NORMAL TEMPS AND MORE LAKE
EFFECT PCPN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 242 PM EDT SUN OCT 20 2013
TIMING OF THE APPROACHING SNOW AND LOWER CEILINGS HAS BEEN VERY
TRICKY TODAY...MADE TRICKIER BY FOG/STRATUS THIS MORNING ACROSS THE
HIGHER ELEVATIONS OF THE W HALF OF UPPER MI. THIS MAINLY INFLUENCED
SAW...WHICH WAS RIGHT ON THE CLEARING LINE THANKS TO LIGHT DOWNSLOPE
WINDS MUCH OF THE MORNING. CEILINGS HAVE BEEN HOVERING BETWEEN HIGH
END MVFR AND VFR EARLY THIS AFTERNOON...WITH THE RAIN/SNOW LINE AND
MVFR TO IFR CEILINGS NEARING FROM N CENTRAL WI THIS AFTERNOON.
EXPECT DETERIORATING CONDITIONS AT ALL 3 SITES...WITH RAIN SLOWLY
MIXING WITH SNOW OVERNIGHT. THE MIX OF RAIN AND SNOW WILL LIKELY
CHANGE OVER TO ALL SNOW AT IWD SHORTLY BEFORE DAYBREAK AS COOLER AIR
RUSHES IN ON FAVORABLE W-NW WINDS. THE CHANGE OVER SHOULD TAKE A
COUPLE MORE HOURS AT CMX...WITH A LOW TEMP IN THE MID 30S OVERNIGHT.
STRONGER W WINDS WILL BE COMMON STARTING 09-15Z W TO E...WITH GUSTS
OF 25-30KTS /STRONGEST AT CMX/...AS CEILINGS SLOWLY IMPROVE AS THE
BULK OF THE MOISTURE EXITS AS THE SFC LOW PUSHES INTO E QUEBEC.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SUN OCT 20 2013
LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER
THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER
GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL
STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST
AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE
LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES
IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE
SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN.
AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW
ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO
THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT
NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR
LSZ265>267.
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ264.
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
243 PM EDT SUN OCT 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SUN OCT 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE
UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER
STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA.
290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS
SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB
TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE
SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED
INTO NW UPPER MI AND ERN LAKE SUPERIOR.
THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND
SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM
WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON
MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL
SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND
ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH
RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS
SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER
TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE
SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES
BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR
BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW
INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN OCT 20 2013
AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES
REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS
AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE
CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH
UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA
(CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT
AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND
OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING
INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES
NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A
SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT.
EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY
AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN.
THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE
GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE
WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB
TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY.
WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON
MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON
AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING
THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE
FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID
OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME
DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE
WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO
FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR
LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE
AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN
INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT
BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO
PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE
EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE
ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS.
THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE
WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE
AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY
PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING
THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING
THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE
DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC
FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH
UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A
GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY
MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS
PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE
LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD
PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW
MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND
OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND
SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE
STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC
INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND
2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH
HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE
TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM
NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT
WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF
MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES
24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE
KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON
MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH
RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME
MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER.
THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END
UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS
(BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL
AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING
6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY
WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO
HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO
HIGHTEN THE AWARENESS.
SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON
TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN
PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST
ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST
OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW
SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE
NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD
BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL
CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL
NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL
FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE
LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE
UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE
EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER
MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD
UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF
SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL
FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY
PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS
OCCURRING THROUGH THE END OF THE WORK WEEK.
THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO
WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES.
BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES
WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND.
WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH
TEMPERATURES REMAINING BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 242 PM EDT SUN OCT 20 2013
TIMING OF THE APPROACHING SNOW AND LOWER CEILINGS HAS BEEN VERY
TRICKY TODAY...MADE TRICKIER BY FOG/STRATUS THIS MORNING ACROSS THE
HIGHER ELEVATIONS OF THE W HALF OF UPPER MI. THIS MAINLY INFLUENCED
SAW...WHICH WAS RIGHT ON THE CLEARING LINE THANKS TO LIGHT DOWNSLOPE
WINDS MUCH OF THE MORNING. CEILINGS HAVE BEEN HOVERING BETWEEN HIGH
END MVFR AND VFR EARLY THIS AFTERNOON...WITH THE RAIN/SNOW LINE AND
MVFR TO IFR CEILINGS NEARING FROM N CENTRAL WI THIS AFTERNOON.
EXPECT DETERIORATING CONDITIONS AT ALL 3 SITES...WITH RAIN SLOWLY
MIXING WITH SNOW OVERNIGHT. THE MIX OF RAIN AND SNOW WILL LIKELY
CHANGE OVER TO ALL SNOW AT IWD SHORTLY BEFORE DAYBREAK AS COOLER AIR
RUSHES IN ON FAVORABLE W-NW WINDS. THE CHANGE OVER SHOULD TAKE A
COUPLE MORE HOURS AT CMX...WITH A LOW TEMP IN THE MID 30S OVERNIGHT.
STRONGER W WINDS WILL BE COMMON STARTING 09-15Z W TO E...WITH GUSTS
OF 25-30KTS /STRONGEST AT CMX/...AS CEILINGS SLOWLY IMPROVE AS THE
BULK OF THE MOISTURE EXITS AS THE SFC LOW PUSHES INTO E QUEBEC.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SUN OCT 20 2013
LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER
THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER
GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL
STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST
AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE
LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES
IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE
SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN.
AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW
ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO
THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT
NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR
LSZ265>267.
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ264.
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
202 PM EDT SUN OCT 20 2013
.SYNOPSIS...
ISSUED AT 335 AM EDT SUN OCT 20 2013
COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE
INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE
GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER
MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST
INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH
TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR
SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 201 PM EDT SUN OCT 20 2013
SCT-BKN STCU DECK HAS EXPANDED ACROSS THE CWA OVER THE LAST FEW
HOURS...LEADING TO PARTLY SUNNY SKIES FOR MOST AREAS. REMAINING
SMALL BATCH OF LAKE INDUCED SHOWERS CONTINUES TO WORK UP THROUGH
THE STRAITS INTO EASTERN UPPER MICHIGAN...AS ANTICIPATED. BUT DRY
WEATHER ELSEWHERE.
UPSTREAM...SFC LOW PRESSURE SLIDING SOUTHEASTWARD THROUGH THE
UPPER MIDWEST IN RESPONSE TO SMALL UPPER JET CORE PUSHING ACROSS
IOWA...AND SUBSTANTIALLY STRONGER SHORT WAVE ENERGY DIVING
SOUTHWARD OUT OF SOUTH-CENTRAL CANADA. INCREASING WARM ADVECTION
AHEAD OF THE LOW ALREADY PUSHING A BAND OF PRECIP THROUGH
WISCONSIN. THIS BATCH OF WARM ADVECTION FORCED PRECIP WILL PIVOT
SW-NE UP INTO NRN MICHIGAN OVER THE NEXT FEW HOURS LEADING TO A
PERIOD RAINFALL ACROSS THE CWA THIS EVENING. MAIN PERIOD OF
RAINFALL LOOKING TO OCCUR BETWEEN 00Z AND 06Z AS SUBSTANTIALLY
WARM AIR SURGES UP INTO NRN MICHIGAN. WILL CATCH A BIT OF A BREAK
DURING THE OVERNIGHT HOURS BEFORE STRONG SHORT WAVE DRIVES ACROSS NRN
MICHIGAN LATE OVERNIGHT THROUGH MONDAY MORNING...AND WRAP AROUND
MOISTURE/COLDER AIR ROTATE INTO THE REGION. TRANSITION DAY ON
MONDAY.
UPDATE ISSUED AT 1036 AM EDT SUN OCT 20 2013
GOT A BIT OF A BREAK DURING THE OVERNIGHT HOURS WITH CLOUDS THINNING/
CLEARING OUT OVER A GOOD PART OF CWA...WELL DOWNWIND OF THE LAKES.
BUT MEANWHILE...LAKE AGGREGATE TROUGH ANALYZED FROM WESTERN LAKE
SUPERIOR DOWN INTO NRN LAKE MICHIGAN THIS MORNING. MESOSCALE SFC
LOW HAS DEVELOPED OVER NRN LAKE MICHIGAN GIVEN THE WEAKER SYNOPTIC
WIND REGIME/SHORELINE ORIENTATION AND OFFSHORE WIND COMPONENT. A
FEW POCKETS OF LAKE INDUCED SHOWERS LINGER WITHIN THIS FEATURE
ACROSS NRN LAKE MICHIGAN (CAN SEE THE LOW LEVEL SPIN IN THE RADAR
DATA...PUSHING UP INTO PARTS OF NW LOWER INTO THE STRAITS AND
EASTERN UPPER.
REST OF TODAY...POTENT SHORT WAVE AND POCKET OF COLDEST AIR OF THE
SEASON ON TRACK TO DROP INTO THE UPPER MIDWEST...THAT WILL
ULTIMATELY DRIVE A DEEPENING SFC LOW/POTENT COLD FRONT THROUGH THE
REGION...LATE TONIGHT AND MONDAY MORNING. AHEAD OF THIS DEVELOPING
SYSTEM...LOW LEVEL FLOW WILL BACK MORE SOUTHERLY AS WE GO THROUGH
THE AFTERNOON...PUSHING REMAINING LAKE INDUCED SHOWERS UP THROUGH
EASTERN UPPER MICHIGAN. PULSE OF LOW-MID LEVEL WARM ADVECTION
FORCING AHEAD OF THAT DEVELOPING SYSTEM ALREADY PRODUCING A BAND
OF PRECIP EXPANDING INTO WESTERN WISCONSIN THIS MORNING. FORCING
LOOKING TO DEVELOP INTO THE W/SW PART OF THE CWA BY LATE
AFTERNOON. GOING FORECAST ALREADY HAS CHANCY POPS OVER THE SW
COUNTIES AND A SLIVER OF EASTERN UPPER MICHIGAN...WHICH LOOKS FINE
FOR NOW.
HAVE TWEAKED SKY FORECASTS FOR THE BALANCE OF THE DAY BASED ON
TRENDS...TO HAVE A LITTLE MORE SUNSHINE THROUGH MIDDAY. ALSO
TWEAKED TEMP CURVE FOR TONIGHT. BIG SURGE OF WARM AIR ALOFT AND
INCREASING SOUTHERLY WINDS SHOULD ACTUALLY RESULT IN FLAT LINE OR
EVEN WARMING TEMPS TONIGHT. JUST HOW WARM DEPENDS ON HOW FAR NORTH
THE SFC WARM FRONT CAN GET...BUT CAN ENVISION SOME LOCATIONS
PUSHING THE HIGH 40S TO NEAR 50 OVERNIGHT...BEFORE IT ALL CRASHES
ON MONDAY WITH FROPA.
UPDATE ISSUED AT 657 AM EDT SUN OCT 20 2013
CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN
UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE
SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE
TO EARLY-MORNING CLOUD COVER.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM EDT SUN OCT 20 2013
MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES
WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE
RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE
TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER
DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED
WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8
TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING
ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF
NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN
WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET
AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND
LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL
DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL
MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW
PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT
AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN
THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY
MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO
TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT
TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS
SYSTEM.
BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY.
CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY
SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER
DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING
TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE
WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A
DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND
WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS
AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF
EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE
ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT
LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH
INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE
AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA
LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE
ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA
AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS
EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST
THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO.
MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN
TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD
FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM EDT SUN OCT 20 2013
CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING
WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN
IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE
LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW
CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW
EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS
A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/
EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN.
MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER
EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW
SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING
THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT
TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS
OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL
BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB
TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z.
MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF
THE DEEPER WRAPAROUND MOISTURE.
COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START
THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY
FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN
UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS
INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF
THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST
DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY
6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE
DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED
MELTING LAYER IS NARROWING BELOW 1K FT.
MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH
FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI.
MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES
BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN
FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO
EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE
FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE
WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB
THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS
RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER
CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE
SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL
SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP
1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A
DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA...
AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH
MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE
EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE
DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT
ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH
PENINSULAS IN THE MORNING.
MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID
40S. AND IT WILL REMAIN BRISK TO WINDY.
REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX
WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD
STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS
OUT OF HER SYSTEM NOW.)
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 201 PM EDT SUN OCT 20 2013
VFR CONDITIONS ANTICIPATED THROUGH THE BALANCE OF THE AFTERNOON
HOURS WITH SCT-BKN CLOUDS.
LOW PRESSURE OVER THE UPPER MIDWEST WINDS UP THIS AFTERNOON BEFORE
SWINGING UP THROUGH THE REGION TONIGHT. SURGE OF WARM AIR AND RESULTING
RAINFALL ARRIVES EARLY THIS EVENING AHEAD OF THE LOW...LOWERING CIGS/VSBYS
TO MVFR FOR MUCH OF THE EVENING HOURS. LOW LEVEL WIND SHEAR ALSO A
GOOD BET THIS EVENING AS LOW LEVEL WINDS RAMP UP.
MAIN BATCH OF RAINFALL EXITS QUICKLY OVERNIGHT...AFTER 06Z...BUT
WITH VFR CIGS PERSISTING THROUGH THE BALANCE OF THE NIGHT. COLD
FRONT SWEEPS THROUGH MONDAY MORNING LEADING TO GUSTIER WESTERLY
WINDS THROUGH MONDAY. MVFR CIGS PERSIST WITH SHOWERS NEAR LAKE
MICHIGAN.
&&
.MARINE...
ISSUED AT 335 AM EDT SUN OCT 20 2013
RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO
INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY
TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE
SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET
OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST
WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER
NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY
LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN
GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE
FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY
MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT
A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE
AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE
ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY
ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT
LAKES!
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345.
LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341-
342-344>346.
LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321-
322.
&&
$$
UPDATE...BA
SYNOPSIS...JZ
SHORT TERM...MB
LONG TERM...JZ
AVIATION...BA
MARINE...MB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
146 PM EDT SUN OCT 20 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN OCT 20 2013
INTERVALS OF SHOWERS WILL CONTINUE THROUGH THE MAJORITY OF THE WEEK
THIS WEEK AS A STRONG SURGE OF COLD CANADIAN AIR TAKES HOLD OF THE
AREA. WAVES OF LOW PRESSURE WILL COMBINE WITH LAKE EFFECT TO BRING
THE OCCASIONAL SHOWERS TO THE AREA. COLD ENOUGH AIR IS EXPECTED TO
MOVE IN TO ALLOW FOR SOME SNOW TO MIX IN AT TIMES WITH THE RAIN
SHOWERS. HIGHS WILL LIKELY REMAIN ONLY IN THE 40S MANY TIMES THIS
WEEK.
&&
.UPDATE...
ISSUED AT 1205 PM EDT SUN OCT 20 2013
I ADDED THUNDERSTORMS TO OUR ZONE FORECASTS TONIGHT. AFTER
LOOKING AT THE 1000 J/KG OF MOST UNSTABLE CAPE OVER LAKE MICHIGAN
EARLY THIS EVENING. RAP AND NAM SOUNDINGS THIS EVENING INTO THE
OVERNIGHT SHOW NO INVERSION TO CAPE THE INSTABILITY...WHICH IS
UNLIKE LAST NIGHT WHEN WE HAD THUNDERSTORMS BUT THE INSTABILITY WAS
CAPED AROUND 120000 FT. THE SOUNDINGS GIVE EQUILIBRIUM LEVELS AS
HIGH AS 350000 FT THIS EVENING. THE CAPE IS SKINNY...BUT GIVEN
THE 50 KNOT LOW LEVEL JET THAT POKES INTO OUR SOUTHWEST CWA BETWEEN
8 PM AND 11 PM... PLUS OUR AREA BEING IN THE EXIT REGION OF THE
POLAR JET TONIGHT. THE NAM THUNDERSTORMS PROBABILITY PROG HAS
NUMBERS AS HIGH AS 60 PCT OVER LAKE MICHIGAN AND 40 PCT INLAND
NORTH OF HOLLAND TO US-131 JUST BEFORE MIDNIGHT. THE SPC 03Z SREF
ALSO FORECASTS THUNDERSTORMS OVER LAKE MICHIGAN INTO SOUTHWEST
LOWER MICHIGAN SIMILAR TO THE NAM THUNDERSTORM PROP CHART. ALL OF
THIS TELLS ME WE SHOULD SEE THUNDERSTORMS DEVELOPING OVER LAKE
MICHIGAN EARLY TONIGHT THEY WILL THEN MOVE INLAND DURING THE MID
EVENING HOURS JUST AHEAD OF THE COLD FRONT. DUE TO THE SOUTHWEST
WINDS THE BEST INSTABILITY (AIDED BY THE WARMTH OF LAKE MICHIGAN)
WILL MOSTLY BE NORTH OF A LINE FROM HOLLAND TO ALMA.
I ALSO INCREASED THE POP TONIGHT SINCE THERE IS LITTLE QUESTION
GIVEN THE WARM LAKE AND DYNAMICS PLUS A DECENT SHOT AT DEEP
MOISTURE THAT THERE WILL BE SHOWERS TONIGHT. ANY STORMS MAY HAVE
SMALL HAIL GIVEN THE FREEZING LEVEL BEING BELOW 7000 FT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 344 AM EDT SUN OCT 20 2013
PCPN TRENDS AND TYPE ARE THE MAIN FOCUS OF THE FCST PACKAGE TODAY.
THE SHOWER ACTIVITY THAT WAS WIDESPREAD ACROSS THE AREA LAST EVENING
IS SCATTERING OUT AND DISSIPATING EARLY THIS MORNING. THIS IS DUE TO
MAINLY THE UPPER FLOW TRANSITIONING TO ANTI-CYCLONIC AS THE LAST
SHORT WAVE IN THIS SEQUENCE IS NOW LIFTING TO THE E/NE THIS MORNING.
WE EXPECT THE SHOWER ACTIVITY TO PRETTY MUCH END FOR A FEW HOURS AS
SHORT WAVE RIDGING BUILDS IN AND WE LOSE THE LOW LEVEL MOISTURE.
SOME BREAKS IN THE CLOUDS WILL BE LIKELY ONCE AGAIN...HOWEVER JUST
AS THE LOW LEVEL MOISTURE MOVES OUT...MID AND HIGH LEVEL MOISTURE
FROM THE NEXT SYSTEM MOVES RIGHT IN.
THE NEXT SYSTEM IN THE SEQUENCE WILL BE BRINGING PCPN TO THE FAR NW
CORNER OF THE CWFA AS EARLY AS LATE THIS AFTERNOON. THIS WAVE IS
CURRENTLY LOCATED NORTH OF LAKE WINNIPEG AND DROPPING SOUTHEAST
QUICKLY. IT WILL MERGE WITH ANOTHER SHORT WAVE COMING INTO THE
DAKOTAS. THE TRACK OF THE SHORT WAVE AND SFC LOW WILL FAVOR THE NRN
SECTION OF THE CWFA FOR THE BEST PCPN CHCS. IT DOES LOOK LIKE THE
ENTIRE CWFA WILL HAVE A CHC OF RAIN AS THE COLD FRONT PASSES THROUGH
THE AREA VERY LATE TONIGHT AND MON MORNING.
THE THREAT OF LAKE EFFECT RAIN SHOWERS WILL BE THERE ON MON WITH
DELTA T/S EXPECTING TO BE AROUND 20C. THE THREAT DOES NOT LOOK TO BE
VERY BIG HOWEVER AS THE DRY SLOT WILL AFFECT THE AREA BEHIND THE
FRONT. MOISTURE PROFILES INDICATE THAT THEY WILL BE DEEP ENOUGH FOR
SOME PCPN TO BE GENERATED AS THE DGZ WILL BARELY BE SATURATED.
INVERSION HEIGHTS ARE SOMEWHAT LOW AS THE UPPER LOW AND CORE OF THE
CYCLONIC FLOW STAYS MAINLY NORTH OF THE AREA.
THE THREAT OF SHOWERS WILL CONTINUE TO BE POSSIBLE MON NIGHT AND
EARLY TUE. THIS IS THE PERIOD WHEN IT LOOKS LIKE WE WILL SEE A
POTENTIAL OF PCPN MIXING WITH OR CHANGING TO SNOW WITH H850 TEMPS
DROPPING TO ALMOST -7C AND FREEZING LEVELS DROPPING BELOW 2000 FT.
THE BEST POTENTIAL OF SEEING SOME SNOW WILL BE UP ACROSS CENTRAL
LOWER MICHIGAN AT THE HIGHER ELEVATIONS. IN ADDITION TO THE
POSSIBILITY OF SNOW...WE CAN NOT RULE OUT THUNDER ALONG THE
LAKESHORE WITH LAKE MODIFIED PARCELS GENERATING OVER 1000 J/KG OF
CAPE AND PARCELS REACHING TO -20C ISOTHERM. WATERSPOUTS WILL ALSO
REMAIN POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 344 AM EDT SUN OCT 20 2013
THERE SEEMS TO BE NO END IN SIGHT TO THE COOL AND UNSETTLED PATTERN
AS DEEP UPPER TROUGHING PERSISTS OVER THE GREAT LAKES REGION THROUGH
ALL OF NEXT WEEK. TEMPERATURES WILL AVERAGE AROUND 10 DEGREES BELOW
NORMAL.
H8 TEMPS ARE PROGGED TO REMAIN RIGHT AROUND -6C THROUGH MOST OF THE
WEEK CREATING EXTREME LAKE INSTABILITY WITH DELTA T/S IN EXCESS OF
20C. OCCASIONAL SHORTWAVES PIVOTING THROUGH THE REGION WILL
PERIODICALLY BOOST INVERSION HEIGHTS AND BRING SLUGS OF DEEPER
MOISTURE THROUGH WHICH WILL ENHANCE THE SHOWER ACTIVITY.
THE FREEZING LEVEL WILL BE AROUND 1500 FT SO WOULD EXPECT TO SEE A
MIXTURE OF RAIN/SNOW/GRAUPEL... ESPECIALLY INLAND FROM WARMING
EFFECTS OF LK MI INCLUDING THE HWY 131 CORRIDOR. SOME ACCUMULATING
WET SNOW LOOKS TO BE A REALISTIC THREAT FOR WEDNESDAY THROUGH
THURSDAY NIGHT WHEN BOTH THE GFS AND ECMWF INDICATE THAT WE WILL BE
ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET CORE WHICH WILL BE
POSITIONED TO OUR WEST AND SOUTH.
WARM ADVECTION IS CURRENTLY PROGGED FOR NEXT SATURDAY AHEAD OF A
SYSTEM DROPPING DOWN FROM THE NORTHWEST. THIS WOULD END THE LAKE
EFFECT TEMPORARILY BUT THE CHANCE OF RAIN WILL CONTINUE DUE TO
ISENTROPIC LIFT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 146 PM EDT SUN OCT 20 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THIS EVENING EVEN
THOUGH A FEW RAIN SHOWERS WILL BE MOVING IN. THERE IS THE OUTSIDE
CHANCE THAT A THUNDERSTORM COULD MOVE THROUGH THE TAF SITES AFTER
00Z...BUT THESE ARE EXPECTED TO BE VERY ISOLATED AND THEY WERE
NOT PUT IN THE TAFS AT THIS POINT.
A STRONG COLD FRONT WILL APPROACH TOWARD DAYBREAK MON. THERE
SHOULD BE A PERIOD OF MVFR AS THIS FRONT COMES THROUGH...ALONG
WITH SCATTERED SHOWERS. THIS SHOULD IMPROVE TO VFR TOWARD MID DAY
MON.
WINDS WILL BE INCREASING THIS EVENING AND CONTINUE INTO MON AS THE
FRONT COMES THROUGH. SSW WINDS AROUND 15 KTS WILL SHIFT TO THE
WEST TOWARD DAYBREAK.
PILOTS SHOULD ALSO KEEP IN MIND THE RISK OF IN-CLOUD ICING INTO
MON. FREEZING LEVELS WILL BE DROPPING AFTER 12Z BEHIND THE COLD
FRONT...TO 2K TO 3K FEET. CLOUD TOPS WILL BE AROUND 6K FEET. IN-
CLOUD TEMPS WILL CONTINUE TO BECOME MORE FAVORABLE FOR ICING
BEYOND 18Z MON.
&&
.MARINE...
ISSUED AT 1205 PM EDT SUN OCT 20 2013
I CONTINUED THE SMALL CRAFT ADVISORY INTO THIS EVENING AND THE
GALE WARNING TONIGHT AND MONDAY. IT SEEMS TO ME THROUGH THAT THE
WINDS WILL START TO DIMINISH MONDAY AFTERNOON. WE MAY BE ABLE TO
DROP THE GALES BY MID AFTERNOON MONDAY.
WATER SPOUTS WILL BE AN ISSUE ONCE THE WINDS DIMINISH BELOW
GALES... SO I CONTINUED THE WATER SPOUTS IN THE NEAR SHORE FOR
MONDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT SUN OCT 20 2013
WE ARE NOT ANTICIPATING ANY HYDROLOGY ISSUES IN THE NEXT WEEK. THE
MAJORITY OF THE PCPN OVER THE NEXT WEEK WILL BE IN THE FORM OF
SCATTERED SHOWERS. THIS TYPE OF PATTERN IS NOT CONDUCIVE FOR HEAVY
RAINFALL WITH PRECIPITABLE WATERS RUNNING AROUND AVERAGE FOR THIS
TIME OF YEAR. MOST LOCATIONS WILL NOT SEE PCPN OVER HALF AN INCH
OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
GALE WARNING FROM 8 PM THIS EVENING TO 5 AM EDT TUESDAY FOR
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...NJJ
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1205 PM EDT SUN OCT 20 2013
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN OCT 20 2013
INTERVALS OF SHOWERS WILL CONTINUE THROUGH THE MAJORITY OF THE WEEK
THIS WEEK AS A STRONG SURGE OF COLD CANADIAN AIR TAKES HOLD OF THE
AREA. WAVES OF LOW PRESSURE WILL COMBINE WITH LAKE EFFECT TO BRING
THE OCCASIONAL SHOWERS TO THE AREA. COLD ENOUGH AIR IS EXPECTED TO
MOVE IN TO ALLOW FOR SOME SNOW TO MIX IN AT TIMES WITH THE RAIN
SHOWERS. HIGHS WILL LIKELY REMAIN ONLY IN THE 40S MANY TIMES THIS
WEEK.
&&
.UPDATE...
ISSUED AT 1205 PM EDT SUN OCT 20 2013
I ADDED THUNDERSTORMS TO OUR ZONE FORECASTS TONIGHT. AFTER
LOOKING AT THE 1000 J/KG OF MOST UNSTABLE CAPE OVER LAKE MICHIGAN
EARLY THIS EVENING. RAP AND NAM SOUNDINGS THIS EVENING INTO THE
OVERNIGHT SHOW NO INVERSION TO CAPE THE INSTABILITY...WHICH IS
UNLIKE LAST NIGHT WHEN WE HAD THUNDERSTORMS BUT THE INSTABILITY WAS
CAPED AROUND 120000 FT. THE SOUNDINGS GIVE EQUILIBRIUM LEVELS AS
HIGH AS 350000 FT THIS EVENING. THE CAPE IS SKINNY...BUT GIVEN
THE 50 KNOT LOW LEVEL JET THAT POKES INTO OUR SOUTHWEST CWA BETWEEN
8 PM AND 11 PM... PLUS OUR AREA BEING IN THE EXIT REGION OF THE
POLAR JET TONIGHT. THE NAM THUNDERSTORMS PROBABILITY PROG HAS
NUMBERS AS HIGH AS 60 PCT OVER LAKE MICHIGAN AND 40 PCT INLAND
NORTH OF HOLLAND TO US-131 JUST BEFORE MIDNIGHT. THE SPC 03Z SREF
ALSO FORECASTS THUNDERSTORMS OVER LAKE MICHIGAN INTO SOUTHWEST
LOWER MICHIGAN SIMILAR TO THE NAM THUNDERSTORM PROP CHART. ALL OF
THIS TELLS ME WE SHOULD SEE THUNDERSTORMS DEVELOPING OVER LAKE
MICHIGAN EARLY TONIGHT THEY WILL THEN MOVE INLAND DURING THE MID
EVENING HOURS JUST AHEAD OF THE COLD FRONT. DUE TO THE SOUTHWEST
WINDS THE BEST INSTABILITY (AIDED BY THE WARMTH OF LAKE MICHIGAN)
WILL MOSTLY BE NORTH OF A LINE FROM HOLLAND TO ALMA.
I ALSO INCREASED THE POP TONIGHT SINCE THERE IS LITTLE QUESTION
GIVEN THE WARM LAKE AND DYNAMICS PLUS A DECENT SHOT AT DEEP
MOISTURE THAT THERE WILL BE SHOWERS TONIGHT. ANY STORMS MAY HAVE
SMALL HAIL GIVEN THE FREEZING LEVEL BEING BELOW 7000 FT.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 344 AM EDT SUN OCT 20 2013
PCPN TRENDS AND TYPE ARE THE MAIN FOCUS OF THE FCST PACKAGE TODAY.
THE SHOWER ACTIVITY THAT WAS WIDESPREAD ACROSS THE AREA LAST EVENING
IS SCATTERING OUT AND DISSIPATING EARLY THIS MORNING. THIS IS DUE TO
MAINLY THE UPPER FLOW TRANSITIONING TO ANTI-CYCLONIC AS THE LAST
SHORT WAVE IN THIS SEQUENCE IS NOW LIFTING TO THE E/NE THIS MORNING.
WE EXPECT THE SHOWER ACTIVITY TO PRETTY MUCH END FOR A FEW HOURS AS
SHORT WAVE RIDGING BUILDS IN AND WE LOSE THE LOW LEVEL MOISTURE.
SOME BREAKS IN THE CLOUDS WILL BE LIKELY ONCE AGAIN...HOWEVER JUST
AS THE LOW LEVEL MOISTURE MOVES OUT...MID AND HIGH LEVEL MOISTURE
FROM THE NEXT SYSTEM MOVES RIGHT IN.
THE NEXT SYSTEM IN THE SEQUENCE WILL BE BRINGING PCPN TO THE FAR NW
CORNER OF THE CWFA AS EARLY AS LATE THIS AFTERNOON. THIS WAVE IS
CURRENTLY LOCATED NORTH OF LAKE WINNIPEG AND DROPPING SOUTHEAST
QUICKLY. IT WILL MERGE WITH ANOTHER SHORT WAVE COMING INTO THE
DAKOTAS. THE TRACK OF THE SHORT WAVE AND SFC LOW WILL FAVOR THE NRN
SECTION OF THE CWFA FOR THE BEST PCPN CHCS. IT DOES LOOK LIKE THE
ENTIRE CWFA WILL HAVE A CHC OF RAIN AS THE COLD FRONT PASSES THROUGH
THE AREA VERY LATE TONIGHT AND MON MORNING.
THE THREAT OF LAKE EFFECT RAIN SHOWERS WILL BE THERE ON MON WITH
DELTA T/S EXPECTING TO BE AROUND 20C. THE THREAT DOES NOT LOOK TO BE
VERY BIG HOWEVER AS THE DRY SLOT WILL AFFECT THE AREA BEHIND THE
FRONT. MOISTURE PROFILES INDICATE THAT THEY WILL BE DEEP ENOUGH FOR
SOME PCPN TO BE GENERATED AS THE DGZ WILL BARELY BE SATURATED.
INVERSION HEIGHTS ARE SOMEWHAT LOW AS THE UPPER LOW AND CORE OF THE
CYCLONIC FLOW STAYS MAINLY NORTH OF THE AREA.
THE THREAT OF SHOWERS WILL CONTINUE TO BE POSSIBLE MON NIGHT AND
EARLY TUE. THIS IS THE PERIOD WHEN IT LOOKS LIKE WE WILL SEE A
POTENTIAL OF PCPN MIXING WITH OR CHANGING TO SNOW WITH H850 TEMPS
DROPPING TO ALMOST -7C AND FREEZING LEVELS DROPPING BELOW 2000 FT.
THE BEST POTENTIAL OF SEEING SOME SNOW WILL BE UP ACROSS CENTRAL
LOWER MICHIGAN AT THE HIGHER ELEVATIONS. IN ADDITION TO THE
POSSIBILITY OF SNOW...WE CAN NOT RULE OUT THUNDER ALONG THE
LAKESHORE WITH LAKE MODIFIED PARCELS GENERATING OVER 1000 J/KG OF
CAPE AND PARCELS REACHING TO -20C ISOTHERM. WATERSPOUTS WILL ALSO
REMAIN POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 344 AM EDT SUN OCT 20 2013
THERE SEEMS TO BE NO END IN SIGHT TO THE COOL AND UNSETTLED PATTERN
AS DEEP UPPER TROUGHING PERSISTS OVER THE GREAT LAKES REGION THROUGH
ALL OF NEXT WEEK. TEMPERATURES WILL AVERAGE AROUND 10 DEGREES BELOW
NORMAL.
H8 TEMPS ARE PROGGED TO REMAIN RIGHT AROUND -6C THROUGH MOST OF THE
WEEK CREATING EXTREME LAKE INSTABILITY WITH DELTA T/S IN EXCESS OF
20C. OCCASIONAL SHORTWAVES PIVOTING THROUGH THE REGION WILL
PERIODICALLY BOOST INVERSION HEIGHTS AND BRING SLUGS OF DEEPER
MOISTURE THROUGH WHICH WILL ENHANCE THE SHOWER ACTIVITY.
THE FREEZING LEVEL WILL BE AROUND 1500 FT SO WOULD EXPECT TO SEE A
MIXTURE OF RAIN/SNOW/GRAUPEL... ESPECIALLY INLAND FROM WARMING
EFFECTS OF LK MI INCLUDING THE HWY 131 CORRIDOR. SOME ACCUMULATING
WET SNOW LOOKS TO BE A REALISTIC THREAT FOR WEDNESDAY THROUGH
THURSDAY NIGHT WHEN BOTH THE GFS AND ECMWF INDICATE THAT WE WILL BE
ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET CORE WHICH WILL BE
POSITIONED TO OUR WEST AND SOUTH.
WARM ADVECTION IS CURRENTLY PROGGED FOR NEXT SATURDAY AHEAD OF A
SYSTEM DROPPING DOWN FROM THE NORTHWEST. THIS WOULD END THE LAKE
EFFECT TEMPORARILY BUT THE CHANCE OF RAIN WILL CONTINUE DUE TO
ISENTROPIC LIFT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 750 AM EDT SUN OCT 20 2013
HIGH CONFIDENCE EXISTS FOR WIDESPREAD VFR CONDITIONS TODAY. THE
NEXT WEATHER MAKER ARRIVES AFTER 00Z TONIGHT WITH WIDESPREAD
SHOWERS AND MVFR CONDITIONS DEVELOPING AT KMKG AND KGRR BY
03Z-06Z. THE SHOWERS SHOULD SPREAD INLAND OVER THE REST OF THE
AREA AFTER 06Z TONIGHT... ALTHOUGH CONDITIONS SOUTH AND EAST OF
GRR WILL LIKELY REMAIN VFR AS THE SHOWERS SHOULD NOT BE AS HEAVY
AND PERSISTENT AS THEY WILL BE AT KMKG AND KGRR. WINDS WILL
INCREASE OUT OF THE SOUTH TO 10 TO 20 KNOTS LATER THIS AFTERNOON
AND BECOME SOUTHWEST OVERNIGHT.
&&
.MARINE...
ISSUED AT 1205 PM EDT SUN OCT 20 2013
I CONTINUED THE SMALL CRAFT ADVISORY INTO THIS EVENING AND THE
GALE WARNING TONIGHT AND MONDAY. IT SEEMS TO ME THROUGH THAT THE
WINDS WILL START TO DIMINISH MONDAY AFTERNOON. WE MAY BE ABLE TO
DROP THE GALES BY MID AFTERNOON MONDAY.
WATER SPOUTS WILL BE AN ISSUE ONCE THE WINDS DIMINISH BELOW
GALES... SO I CONTINUED THE WATER SPOUTS IN THE NEAR SHORE FOR
MONDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT SUN OCT 20 2013
WE ARE NOT ANTICIPATING ANY HYDROLOGY ISSUES IN THE NEXT WEEK. THE
MAJORITY OF THE PCPN OVER THE NEXT WEEK WILL BE IN THE FORM OF
SCATTERED SHOWERS. THIS TYPE OF PATTERN IS NOT CONDUCIVE FOR HEAVY
RAINFALL WITH PRECIPITABLE WATERS RUNNING AROUND AVERAGE FOR THIS
TIME OF YEAR. MOST LOCATIONS WILL NOT SEE PCPN OVER HALF AN INCH
OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
GALE WARNING FROM 8 PM THIS EVENING TO 5 AM EDT TUESDAY FOR
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...NJJ
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1036 AM EDT SUN OCT 20 2013
.SYNOPSIS...
ISSUED AT 335 AM EDT SUN OCT 20 2013
COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE
INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE
GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER
MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST
INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH
TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR
SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1036 AM EDT SUN OCT 20 2013
GOT A BIT OF A BREAK DURING THE OVERNIGHT HOURS WITH CLOUDS THINNING/
CLEARING OUT OVER A GOOD PART OF CWA...WELL DOWNWIND OF THE LAKES.
BUT MEANWHILE...LAKE AGGREGATE TROUGH ANALYZED FROM WESTERN LAKE
SUPERIOR DOWN INTO NRN LAKE MICHIGAN THIS MORNING. MESOSCALE SFC
LOW HAS DEVELOPED OVER NRN LAKE MICHIGAN GIVEN THE WEAKER SYNOPTIC
WIND REGIME/SHORELINE ORIENTATION AND OFFSHORE WIND COMPONENT. A
FEW POCKETS OF LAKE INDUCED SHOWERS LINGER WITHIN THIS FEATURE
ACROSS NRN LAKE MICHIGAN (CAN SEE THE LOW LEVEL SPIN IN THE RADAR
DATA...PUSHING UP INTO PARTS OF NW LOWER INTO THE STRAITS AND
EASTERN UPPER.
REST OF TODAY...POTENT SHORT WAVE AND POCKET OF COLDEST AIR OF THE
SEASON ON TRACK TO DROP INTO THE UPPER MIDWEST...THAT WILL
ULTIMATELY DRIVE A DEEPENING SFC LOW/POTENT COLD FRONT THROUGH THE
REGION...LATE TONIGHT AND MONDAY MORNING. AHEAD OF THIS DEVELOPING
SYSTEM...LOW LEVEL FLOW WILL BACK MORE SOUTHERLY AS WE GO THROUGH
THE AFTERNOON...PUSHING REMAINING LAKE INDUCED SHOWERS UP THROUGH
EASTERN UPPER MICHIGAN. PULSE OF LOW-MID LEVEL WARM ADVECTION
FORCING AHEAD OF THAT DEVELOPING SYSTEM ALREADY PRODUCING A BAND
OF PRECIP EXPANDING INTO WESTERN WISCONSIN THIS MORNING. FORCING
LOOKING TO DEVELOP INTO THE W/SW PART OF THE CWA BY LATE
AFTERNOON. GOING FORECAST ALREADY HAS CHANCY POPS OVER THE SW
COUNTIES AND A SLIVER OF EASTERN UPPER MICHIGAN...WHICH LOOKS FINE
FOR NOW.
HAVE TWEAKED SKY FORECASTS FOR THE BALANCE OF THE DAY BASED ON
TRENDS...TO HAVE A LITTLE MORE SUNSHINE THROUGH MIDDAY. ALSO
TWEAKED TEMP CURVE FOR TONIGHT. BIG SURGE OF WARM AIR ALOFT AND
INCREASING SOUTHERLY WINDS SHOULD ACTUALLY RESULT IN FLAT LINE OR
EVEN WARMING TEMPS TONIGHT. JUST HOW WARM DEPENDS ON HOW FAR NORTH
THE SFC WARM FRONT CAN GET...BUT CAN ENVISION SOME LOCATIONS
PUSHING THE HIGH 40S TO NEAR 50 OVERNIGHT...BEFORE IT ALL CRASHES
ON MONDAY WITH FROPA.
UPDATE ISSUED AT 657 AM EDT SUN OCT 20 2013
CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN
UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE
SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE
TO EARLY-MORNING CLOUD COVER.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM EDT SUN OCT 20 2013
MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES
WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE
RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE
TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER
DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED
WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8
TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING
ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF
NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN
WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET
AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND
LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL
DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL
MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW
PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT
AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN
THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY
MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO
TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT
TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS
SYSTEM.
BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY.
CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY
SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER
DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING
TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE
WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A
DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND
WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS
AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF
EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE
ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT
LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH
INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE
AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA
LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE
ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA
AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS
EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST
THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO.
MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN
TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD
FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM EDT SUN OCT 20 2013
CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING
WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN
IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE
LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW
CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW
EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS
A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/
EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN.
MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER
EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW
SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING
THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT
TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS
OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL
BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB
TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z.
MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF
THE DEEPER WRAPAROUND MOISTURE.
COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START
THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY
FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN
UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS
INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF
THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST
DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY
6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE
DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED
MELTING LAYER IS NARROWING BELOW 1K FT.
MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH
FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI.
MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES
BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN
FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO
EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE
FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE
WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB
THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS
RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER
CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE
SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL
SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP
1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A
DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA...
AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH
MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE
EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE
DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT
ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH
PENINSULAS IN THE MORNING.
MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID
40S. AND IT WILL REMAIN BRISK TO WINDY.
REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX
WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD
STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS
OUT OF HER SYSTEM NOW.)
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 657 AM EDT SUN OCT 20 2013
SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN
LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC
FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE.
OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH
MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY...ESPECIALLY
TONIGHT. WESTERLY WINDS UNDER 10 KTS TONIGHT WILL SHIFT TO THE
S/SW ON SUNDAY AHEAD OF DEEPENING LOW PRESSURE SLIDING INTO THE
UPPER MISSISSIPPI VALLEY. LLWS TONIGHT AT ALL TAF SITES FOR PART
OF TONIGHT.
&&
.MARINE...
ISSUED AT 335 AM EDT SUN OCT 20 2013
RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO
INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY
TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE
SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET
OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST
WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER
NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY
LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN
GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE
FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY
MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT
A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE
AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE
ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY
ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT
LAKES!
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345.
LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341-
342-344>346.
LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321-
322.
&&
$$
UPDATE...BA
SYNOPSIS...JZ
SHORT TERM...MB
LONG TERM...JZ
AVIATION...JZ
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT SUN OCT 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SUN OCT 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE
UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER
STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA.
290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS
SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB
TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE
SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED
INTO NW UPPER MI AND ERN LAKE SUPERIOR.
THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND
SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM
WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON
MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL
SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND
ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH
RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS
SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER
TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE
SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES
BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR
BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW
INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN OCT 20 2013
AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES
REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS
AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE
CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH
UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA
(CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT
AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND
OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING
INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES
NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A
SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT.
EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY
AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN.
THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE
GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE
WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB
TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY.
WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON
MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON
AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING
THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE
FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID
OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME
DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE
WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO
FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR
LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE
AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN
INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT
BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO
PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE
EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE
ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS.
THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE
WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE
AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY
PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING
THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING
THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE
DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC
FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH
UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A
GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY
MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS
PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE
LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD
PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW
MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND
OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND
SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE
STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC
INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND
2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH
HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE
TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM
NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT
WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF
MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES
24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE
KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON
MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH
RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME
MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER.
THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END
UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS
(BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL
AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING
6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY
WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO
HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO
HIGHTEN THE AWARENESS.
SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON
TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN
PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST
ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST
OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW
SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE
NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD
BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL
CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL
NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL
FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE
LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE
UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE
EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER
MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD
UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF
SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL
FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY
PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS
OCCURRING THROUGH THE END OF THE WORK WEEK.
THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO
WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES.
BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES
WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND.
WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH
TEMPERATURES REMAINING BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 733 AM EDT SUN OCT 20 2013
ARRIVAL OF A WEAK HIGH PRESSURE RIDGE SHOULD BRING VFR CONDITIONS TO
ALL THE SITES FOR MUCH OF THE DAY TODAY...BUT THICKER CLOUDS AND
RAIN WILL ARRIVE SW TO NE SUN AFTERNOON AND EVENING AHEAD OF LOW
PRES MOVING THROUGH THE UPPER LAKES. EXPECT CONDITIONS TO
DETERIORATE TO MVFR AT ALL 3 SITES AND EVEN IFR AT IWD UNDER STEADY
RA WITH UPSLOPE NE WIND. SAW AND CMX ARE ALSO EXPECTED TO DROP TO
IFR WITH THE PERSISTENT LIGHT RAIN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SUN OCT 20 2013
LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER
THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER
GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL
STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST
AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE
LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES
IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE
SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN.
AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW
ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO
THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT
NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR
LSZ265>267.
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ264.
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
700 AM EDT SUN OCT 20 2013
.SYNOPSIS...
ISSUED AT 335 AM EDT SUN OCT 20 2013
COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE
INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE
GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER
MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST
INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH
TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR
SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 657 AM EDT SUN OCT 20 2013
CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN
UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE
SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE
TO EARLY-MORNING CLOUD COVER.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM EDT SUN OCT 20 2013
MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES
WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE
RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE
TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER
DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED
WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8
TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING
ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF
NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN
WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET
AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND
LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL
DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL
MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW
PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT
AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN
THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY
MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO
TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT
TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS
SYSTEM.
BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY.
CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY
SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER
DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING
TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE
WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A
DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND
WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS
AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF
EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE
ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT
LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH
INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE
AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA
LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE
ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA
AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS
EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST
THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO.
MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN
TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD
FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM EDT SUN OCT 20 2013
CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING
WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN
IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE
LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW
CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW
EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS
A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/
EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN.
MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER
EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW
SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING
THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT
TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS
OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL
BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB
TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z.
MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF
THE DEEPER WRAPAROUND MOISTURE.
COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START
THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY
FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN
UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS
INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF
THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST
DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY
6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE
DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED
MELTING LAYER IS NARROWING BELOW 1K FT.
MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH
FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI.
MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES
BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN
FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO
EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE
FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE
WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB
THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS
RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER
CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE
SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL
SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP
1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A
DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA...
AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH
MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE
EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE
DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT
ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH
PENINSULAS IN THE MORNING.
MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID
40S. AND IT WILL REMAIN BRISK TO WINDY.
REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX
WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD
STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS
OUT OF HER SYSTEM NOW.)
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 657 AM EDT SUN OCT 20 2013
SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN
LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC
FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE.
OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH
MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY...ESPECIALLY
TONIGHT. WESTERLY WINDS UNDER 10 KTS TONIGHT WILL SHIFT TO THE
S/SW ON SUNDAY AHEAD OF DEEPENING LOW PRESSURE SLIDING INTO THE
UPPER MISSISSIPPI VALLEY. LLWS TONIGHT AT ALL TAF SITES FOR PART
OF TONIGHT.
&&
.MARINE...
ISSUED AT 335 AM EDT SUN OCT 20 2013
RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO
INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY
TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE
SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET
OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST
WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER
NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY
LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN
GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE
FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY
MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT
A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE
AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE
ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY
ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT
LAKES!
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345.
LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341-
342-344>346.
LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321-
322.
&&
$$
UPDATE...JZ
SYNOPSIS...JZ
SHORT TERM...MB
LONG TERM...JZ
AVIATION...JZ
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
512 AM EDT SUN OCT 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SUN OCT 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE
UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER
STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA.
290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS
SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB
TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE
SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED
INTO NW UPPER MI AND ERN LAKE SUPERIOR.
THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND
SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM
WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON
MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL
SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND
ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH
RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS
SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER
TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE
SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES
BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR
BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW
INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN OCT 20 2013
AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES
REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS
AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE
CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH
UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA
(CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT
AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND
OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING
INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES
NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A
SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT.
EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY
AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN.
THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE
GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE
WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB
TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY.
WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON
MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON
AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING
THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE
FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID
OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME
DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE
WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO
FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR
LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE
AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN
INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT
BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO
PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE
EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE
ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS.
THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE
WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE
AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY
PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING
THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING
THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE
DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC
FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH
UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A
GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY
MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS
PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE
LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD
PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW
MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND
OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND
SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE
STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC
INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND
2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH
HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE
TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM
NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT
WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF
MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES
24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE
KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON
MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH
RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME
MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER.
THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END
UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS
(BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL
AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING
6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY
WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO
HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO
HIGHTEN THE AWARENESS.
SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON
TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN
PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST
ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST
OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW
SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE
NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD
BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL
CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL
NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL
FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE
LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE
UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE
EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER
MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD
UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF
SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL
FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY
PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS
OCCURRING THROUGH THE END OF THE WORK WEEK.
THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO
WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES.
BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES
WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND.
WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH
TEMPERATURES REMAINING BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 129 AM EDT SUN OCT 20 2013
WITH AN UPSLOPE W WIND COMPONENT AND FAIRLY MOIST/CHILLY AIRMASS
FLOWING OVER THE RELATIVELY WARM WATERS OF WRN LK SUP...SOME LO CLDS
AND AT LEAST OCNL MVFR CIGS WL IMPACT IWD AND ESPECIALLY CMX THRU
MUCH OF THE NGT. DOWNSLOPE NATURE OF THE FLOW SHOULD MAINTAIN VFR
CONDITIONS AT SAW. ARRIVAL OF WEAK HI PRES RDG SHOULD BRING VFR WX
TO ALL THE SITES FOR MUCH OF THE DAY SUN...BUT THICKER CLDS/RA WL
ARRIVE SW TO NE SUN AFTN/EVNG AHEAD OF LO PRES MOVING THRU THE UPR
LKS. EXPECT CONDITIONS TO DETERIORATE TO MVFR AT ALL 3 SITES AND
EVEN IFR AT IWD UNDER STEADY RA WITH UPSLOPE N WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SUN OCT 20 2013
LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER
THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER
GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL
STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST
AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE
LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES
IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE
SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN.
AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW
ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO
THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT
NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR
LSZ265>267.
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ264.
GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
338 AM EDT SUN OCT 20 2013
.SYNOPSIS...
ISSUED AT 335 AM EDT SUN OCT 20 2013
COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE
INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE
GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER
MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST
INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH
TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR
SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 335 AM EDT SUN OCT 20 2013
MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES
WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE
RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE
TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER
DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED
WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8
TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING
ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF
NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN
WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET
AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND
LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL
DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL
MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW
PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT
AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN
THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY
MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO
TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT
TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS
SYSTEM.
BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY.
CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY
SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER
DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING
TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE
WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A
DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND
WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS
AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF
EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE
ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT
LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH
INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE
AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA
LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE
ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA
AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS
EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST
THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO.
MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN
TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD
FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM EDT SUN OCT 20 2013
CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING
WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN
IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE
LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW
CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW
EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS
A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/
EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN.
MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER
EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW
SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING
THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT
TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS
OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL
BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB
TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z.
MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF
THE DEEPER WRAPAROUND MOISTURE.
COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START
THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY
FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN
UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS
INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF
THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST
DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY
6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE
DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED
MELTING LAYER IS NARROWING BELOW 1K FT.
MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH
FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI.
MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES
BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN
FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO
EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE
FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE
WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB
THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS
RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER
CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE
SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL
SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP
1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A
DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA...
AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH
MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE
EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE
DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT
ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH
PENINSULAS IN THE MORNING.
MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID
40S. AND IT WILL REMAIN BRISK TO WINDY.
REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX
WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD
STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS
OUT OF HER SYSTEM NOW.)
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1100 PM EDT SAT OCT 19 2013
SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN
LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC
FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE.
OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH
MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY. WESTERLY WINDS
UNDER 10 KTS TONIGHT WILL SHIFT TO THE S/SW ON SUNDAY AHEAD OF
DEEPENING LOW PRESSURE SLIDING INTO THE UPPER MISSISSIPPI VALLEY.
&&
.MARINE...
ISSUED AT 335 AM EDT SUN OCT 20 2013
RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO
INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY
TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE
SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET
OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST
WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER
NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY
LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN
GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE
FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY
MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT
A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE
AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE
ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY
ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT
LAKES!
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345.
LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341-
342-344>346.
LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321-
322.
&&
$$
SYNOPSIS...JZ
SHORT TERM...MB
LONG TERM...JZ
AVIATION...MR
MARINE...MB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
711 PM CDT MON OCT 21 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 325 PM CDT MON OCT 21 2013
TONIGHT THRU TUESDAY...COLD PATTERN WILL REMAIN IN PLACE THRU TMRW
AS A DEEP UPPER LEVEL LOW WITHIN A LONGWAVE TROUGH OVER ERN CANADA
DIPS INTO THE GREAT LAKES. THE LOW WILL SHIFT TO THE E...PUTTING
PRONOUNCED NW FLOW OVER THE AREA...AHEAD OF A LARGE LONGWAVE RIDGE
OVER THE WRN CONUS. WITHIN THE FLOW OF THIS NW FLOW...A CLIPPER-TYPE
LOW PRES SYSTEM WILL DRIVE SE FROM WRN CANADA THRU THE DAKOTAS ON
ITS WAY INTO IA/MO/IL. THE LOW LOOKS TO BE DISPLACED FAR ENOUGH TO
THE S AND W SUCH THAT APPRECIABLE SNOWFALL WILL NOT BE AN ISSUE...
SAVE FOR AN INCH OR SO FOR A COUPLE OF COUNTIES ALONG THE IA BORDER
OVERNIGHT. THIS LOW WILL THEN QUICKLY SHIFT OFF WELL TO THE SE DURG
THE DAY TMRW WHILE HIGH PRES MOVES IN BEHIND THE LOW FOR TMRW. TEMPS
WILL CONTINUE TO RUN ABOUT 5-10 DEGREES BELOW NORMAL...WITH LOWS
TONIGHT DROPPING INTO THE MID-UPR 20S. ALTHOUGH THE WFO MPX
FROST/FREEZE PROGRAM HAS BEEN SUSPENDED FOR THE SEASON...IT IS WORTH
NOTING THAT MOST LOCALES WILL RECEIVE THE FIRST HARD FREEZE OF THE
SEASON TONIGHT. HIGHS TMRW WILL THEN ONLY REACH THE LWR 40S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 325 PM CDT MON OCT 21 2013
THE SECOND SYSTEM IS NEARLY ON THE SAME TRACK AS TUESDAY ALBERTA
TYPE CLIPPER AS IT MOVES ACROSS THE MIDWEST...AND MAINLY AFFECTING
FAR SW/SC MN WEDNESDAY MORNING. RESIDUAL MOISTURE CONTINUES
ON THURSDAY IN THE FAVORED DENDRITIC ZONE ACROSS THE REGION.
HOWEVER MOISTURE DEPTH REMAINS SHALLOW IN THIS ZONE WHICH WILL
LEAD TO OCCASIONAL FLURRIES/SPRINKLES AT BEST.
AFTER THURSDAY...THERE WILL BE A SLIGHT CHG IN THE WEATHER PATTERN
AS WARMER AIR BEGINS TO MOVE ACROSS THE PLAINS...AND INTO THE
UPPER MIDWEST AS THE FLOW PATTERN ALOFT BECOMES MORE WEST/SW BY
THIS WEEKEND. AS THIS PATTERN DEVELOPS...MOST OF THE ENERGY AND
MOISTURE WILL LIFT ACROSS CANADA AND THE NORTHERN GREAT
LAKES...KEEPING OUR REGION DRY...AND PERHAPS SLIGHTLY NEAR OR ABV
NORMAL BY SAT/SUN. AT THE SAME TYPE WITH THE WARMER FLOW
DEVELOPING...A STORM SYSTEM IS EXPECTED TO ORGANIZE ACROSS THE
NORTHERN ROCKIES...THEN DIVE SOUTH INTO THE SOUTHERN ROCKIES
EARLY NEXT WEEK. ALTHOUGH THE GFS/EC HAVE ONLY DEVELOPED THIS TYPE
OF WEATHER PATTERN CHG IN THE PAST FEW MODEL RUNS...THIS TYPE OF
PATTERN IS MORE CONDUCIVE OF A STRONG STORM SYSTEM TO DEVELOP
ACROSS THE PLAINS...AND POSSIBLY AFFECTING THE UPPER MIDWEST/GREAT
LAKES REGION BY THE MIDDLE OF NEXT WEEK. FORECASTERS NEED TO
MONITOR TRENDS ON THIS TYPE OF LONG WAVE PATTERN CHG...AND HOW
CRITICAL THICKNESS VALUES ORIENT ALONG THE THERMAL BOUNDARY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 711 PM CDT MON OCT 21 2013
CEILING GENERALLY 040-050 NE OF I-94 FROM AXN TO MSP THEN SE TO
RGK. LATEST RAP DOES IMPLY SCATTERED CLOUDS EARLY THIS EVENING AT
AXN/STC/MSP...BUT SLOW MOVING SATELLITE TRENDS SUGGEST TAKING A
MORE CONSERVATIVE COURSE AT AXN/STC. WILL NOT GO SCATTERED AT AXN/STC
UNTIL LATER THIS EVENING. NEXT SURGE OF BKN040-050 SHOULD ARRIVE
TUESDAY AFTER 15Z IN NNW FLOW. AM A LITTLE SKEPTICAL OF SEEING MUCH
OVC LATE TONIGHT INTO TUESDAY MORNING SINCE LOW-MID LEVEL HEIGHTS
LOOK TO BE RISING EVER SO SLIGHTLY THROUGH 15Z...THEN SOME
CYCLONIC FLOW RETURNS. THUS WILL PROBABLY SEE SOME BROKEN040
DEVELOPING AROUND 16Z OR SO. PROFILES AS VIEWED IN BUFKIT INDICATE
SOME POTENTIAL FOR GUSTS OF 15-20 KTS TOMORROW MIDDAY AMIDST LOW
LEVEL ADIABATIC PROFILES.
MEANWHILE...IN SW MN...CLIPPER MENTIONED IN SHORT-TERM WILL LIKELY
PASS FAR ENOUGH WEST AND SOUTH OF KRWF TO ONLY BRING SOME OVC MID
LEVEL CLOUDS. LIGHT SNOW SHOULD BE FARTHER SOUTH AND WEST. FEW
FLURRIES AT BEST AT KRWF.
KMSP...BROKEN CEILINGS AROUND 045 SHOULD PERSIST MUCH OF THE NIGHT
OVER THE NORTHEAST TWIN CITIES METRO...JUST NORTH AND NORTHEAST
OF THE AIRFIELD. NEXT SURGE OF BKN040 MOST LIKELY WILL NOT ARRIVE
UNTIL TUESDAY 15Z OR SO. LOOKS LIKE THERE WILL BE SOME GUSTS
TOMORROW AROUND 15-18 KTS DUE TO LOW LEVEL ADIABATIC TEMPERATURE
PROFILES.
/OUTLOOK FOR KMSP/
WED...VFR. SW WIND LESS THAN 5 KT BECMG NW 5-10 KT.
THU...VFR. NW WIND 10-15 KT.
FRI...VFR. SW WIND 10 KT INCRG TO 15 TO 20 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JPC
LONG TERM...JLT
AVIATION...TDK
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
131 PM CDT SUN OCT 20 2013
.SHORT/LONG TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 433 AM CDT SUN OCT 20 2013
PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE
PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES
FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL
SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK.
ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER
SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES
MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE
HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR
FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT
MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM
IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY
OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES
SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE
ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE
LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA
REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE
BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES
INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING
THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY
SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN
QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF
I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS
MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN
MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE
LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT
RAIN/DRIZZLE SCENARIO.
BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS
COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE
REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST
ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD
SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT
OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE
MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN
BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN
SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS
THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER
MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE
IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC
AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1259 PM CDT SUN OCT 20 2013
THIS TAF CYCLE HAS PROVED DIFFICULT...WITH A FEW AMENDMENTS/
CORRECTIONS REQUIRED WITHIN MINUTES OF THE INITIAL SET BEING
ISSUED. A DRY SLOT ACROSS SOUTH CENTRAL MN HAS BROUGHT VFR
CONDITIONS THERE TEMPORARILY...BUT IT IS ALREADY BEGINNING TO FILL
BACK IN WITH CLOUDS ON THE BACKSIDE OF THE LOW WHICH ARE ACCELERATING
EASTWARD. CIGS WITHIN THIS AREA OF WRAP AROUND CLOUDS ARE SOLIDLY
MVFR...WITH SOME LOCATIONS AS LOW AS IFR...PARTICULARLY OVER
NORTHEASTERN SOUTH DAKOTA AND WEST CENTRAL MN. FURTHER EAST...SNOW
CONTINUES ACROSS EAST CENTRAL MN WHERE VSBYS REMAIN LESS THAN 1
MILE. THE STEADY PRECIPITATION WILL TAPER OFF EARLY THIS
AFTERNOON WITH THE TAF SITES BECOMING MAINLY SPORADIC -RA OR -DZ
FOR THE REST OF THE AFTERNOON. CONFIDENCE REMAINS QUITE LOW WITH
REGARD TO HOW LOW CIGS WILL BECOME THIS EVENING BEFORE DRIER AIR
ARRIVES FROM EASTERN NORTH DAKOTA. MUCH OF THE GUIDANCE APPEARS
TOO OPTIMISTIC GIVEN CURRENT CONDITIONS SO WILL CONTINUE THE TREND
DOWNWARD INTO EARLY EVENING. THE DRIER AIR SHOULD ERODE THE LOWER
CIGS OVERNIGHT AND MONDAY MORNING.
KMSP...THE SHORT STINT OF VFR CIGS IS OVER FOR NOW. CIGS CONTINUE
TO CRASH TO THE WEST WITH MVFR AND SUB 017 CIGS EXPECTED A LITTLE
LATER THIS AFTERNOON. EVENTUALLY DRIER AIR WILL ERODE THE LOWER
CIGS OVERNIGHT...BUT CONFIDENCE IS QUITE LOW AS TO WHEN THIS WILL
OCCUR.
/OUTLOOK FOR KMSP/
MON NIGHT...VFR. WINDS WNW 5-10 KTS.
TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 10 KTS.
WED...MVFR CIGS POSSIBLE. WINDS NW AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JRB
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
654 AM CDT SUN OCT 20 2013
.SHORT/LONG TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 433 AM CDT SUN OCT 20 2013
PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE
PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES
FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL
SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK.
ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER
SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES
MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE
HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR
FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT
MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM
IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY
OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES
SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE
ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE
LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA
REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE
BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES
INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING
THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY
SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN
QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF
I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS
MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN
MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE
LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT
RAIN/DRIZZLE SCENARIO.
BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS
COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE
REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST
ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD
SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT
OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE
MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN
BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN
SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS
THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER
MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE
IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC
AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 621 AM CDT SUN OCT 20 2013
A COMPLEX AND MESSY TAF PERIOD IS AHEAD AS A CLIPPER SYSTEM DIVES
SOUTHEAST ACROSS SOUTHERN MINNESOTA TODAY. PRECIPITATION CONTINUES
TO MOVE EAST AND IS NOW APPROACHING KMSP. IT SHOULD BEGIN AS
SNOW...CHANGE QUICKLY TO RAIN WITH MAYBE SOME SNOW MIXED IN AT THE
TAF SITES FOR AN HOUR OR SO THIS MORNING AS WELL AS SOME
DRIZZLE. DONT REALLY HAVE STRONG UPWARD VERTICAL MOTION SO DO NOT
EXPECT DYNAMIC COOLING OF ANY SORT TO FOUL UP THE PRECIPITATION
TYPE. BOUNDARY LAYER TEMPS WARM THIS MORNING WITH WARM AIR
ADVECTION IN PLACE AND THERMAL PROFILES SUPPORT A QUICK CHANGE
FROM SNOW TO RAIN. QUICK PEEK AT THE KMPX SOUNDING SHOWS A LOT
MORE MOISTURE ABOVE 700MB AS COMPARED TO LAST EVENINGS SOUNDING.
HIGH RES MODELS INDICATE DRY AIR TO WORK IN FROM THE SOUTHWEST
AFTER 20Z AND AS A RESULT PRECIP SHOULD END AROUND 20-21Z IN MOST
AREAS...MAYBE SOME DRIZZLE CONTINUING AT AXN/STC AND OVER INTO
WESTERN WISCONSIN. GUIDANCE WANTS TO RAISE CIGS TOO MUCH FOR THE
EVENING AND OVERNIGHT HOURS. MUCH DRIER AIR COMES IN ALOFT HOWEVER
THE LOWEST 4000 FEET OF THE ATMOSPHERE REMAIN QUITE MOIST SO WILL
HOLD ON TO MVRF CIGS THROUGH THE PERIOD. WINDS WILL BE QUITE GUSTY
AT AXN/RWF THIS AFTERNOON AND EARLY EVENING.
KMSP...ONSET OF PRECIP WILL OCCUR BY 12Z AND THAT SHOULD BE
SNOW PELLETS...SNOW AND OR DRIZZLE. AFTER 13Z WILL SEE A MIX AT
TIMES OF RAIN AND SNOW AND ALL RAIN BY 14Z AS THE BOUNDARY LEVEL
WARMS SLIGHTLY. WARM AIR ADVECTION PATTERN FEATURES A SLOW UPWARD
ASCENT OF AIR HENCE THE OPPORTUNITIES FOR DRIZZLE OR LIGHT RAIN.
BIGGEST UNCERTAINTY WILL BE CIGS TODAY THROUGH MONDAY MORNING. WAS
OPTIMISTIC FOR TODAY AND PESSIMISTIC FOR THE OVERNIGHT HOURS AS
COMPARED TO GUIDANCE. HOWEVER COULD EASILY SEE LOWER CIGS THIS
MORNING AND AFTERNOON AND THAT WILL HAVE TO BE WATCHED CLOSELY AS
THE WARM FRONT WILL BE JUST NORTH OF THE METRO AND MSP WILL BE
SOMEWHERE BETWEEN THE IFR CIGS TO THE NORTH AND VFR OR MVFR CIGS
TO THE SOUTH IN THE WARMER AIR.
/OUTLOOK FOR KMSP/
MON...MVFR IN AM...VFR IN AFTERNOON. WINDS NW AT 10-15KT.
TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 5-10 KTS.
WED...MVFR CIGS POSSIBLE. WINDS W AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JRB
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
435 AM CDT SUN OCT 20 2013
.SHORT/LONG TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 433 AM CDT SUN OCT 20 2013
PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE
PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES
FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL
SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK.
ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER
SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES
MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE
HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR
FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT
MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM
IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY
OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES
SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE
ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE
LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA
REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE
BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES
INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING
THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY
SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN
QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF
I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS
MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN
MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE
LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT
RAIN/DRIZZLE SCENARIO.
BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS
COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE
REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST
ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD
SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT
OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE
MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN
BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN
SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS
THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER
MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE
IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC
AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CDT SAT OCT 19 2013
A COMPLEX TAF PERIOD IS AHEAD AS A CLIPPER SYSTEM DIVES SOUTHEAST
ACROSS SOUTHERN MINNESOTA SUNDAY. PRECIPITATION WILL BEGIN TO
PUSH INTO WESTERN MN LATE TONIGHT AND SPREAD EAST INTO WISCONSIN
LATE SUNDAY MORNING. THERMAL PROFILES INDICATE SNOW FOR MUCH OF
CENTRAL MN...WITH A BIT OF SNOW POSSIBLE AT THE ONSET ACROSS
EASTERN MN AND WESTERN WI. THINK TEMPERATURES ARE OVERDONE ON
MOS...WHICH LEADS TO LOWER RH NEAR THE SURFACE AND THUS HIGHER
CIGS. WENT MUCH MORE PESSIMISTIC WITH THE CIGS NORTH OF THE LOW
TRACK AS INDICATED BY FORECAST SOUNDINGS AND HOPWRF MODEL.
KMSP...ONSET OF PRECIP CONTINUES TO LOOK LIKE 13 OR 14Z WITH SNOW
POSSIBLY MIXED WITH THE RAIN FOR A BRIEF TIME. BIGGEST
UNCERTAINTY WILL BE CIGS SUNDAY. THE WARM FRONT WILL BISECT THE
METRO AND MSP WILL BE SOMEWHERE BETWEEN THE IFR CIGS TO THE NORTH
AND VFR OR MVFR CIGS TO THE SOUTH IN THE WARMER AIR. A SLIGHT
NORTHWARD SHIFT OF THE FORECAST TRACK HAS LED TO A CONTINUATION
OF MVFR CIGS.
/OUTLOOK FOR KMSP/
MON...VFR WITH -RA/SN POSSIBLE. WINDS NW AT 15G25KT.
TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 5-10 KTS.
WED...MVFR CIGS POSSIBLE. WINDS W AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JRB
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
729 PM EDT MON OCT 21 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC
TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE
AREA EARLY TUESDAY MORNING. BEHIND THE FRONT EXPECT MUCH COLDER
AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK.
CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT
RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TUESDAY/...
715 PM UPDATE...
NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN
ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN
IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES
THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY
NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT
UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON
TARGET AT THIS TIME.
PREV DISCUSSION BLO...
BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN
CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT
APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION
VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS
IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS
THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH
PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY
ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS
HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING
ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND
FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS
TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH
OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH
SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY
AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS
IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE
CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE
AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN
FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY
OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE
WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS
DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY.
FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY
ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY
UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE
BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE
40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR
FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING
FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN
COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE
OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE
BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS
OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY.
MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT
ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY
WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD
CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES
LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW
ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS
THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS
RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY
MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM
TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE
TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE
SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS
IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING
OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO
PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT
THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO
DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH
SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
00Z UPDATE...
VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY EVENING AHEAD OF AN
APPROACHING COLD FRONT FROM THE WEST. WINDS WILL WEAKEN QUICKLY
AFTER SUNSET AS WE LOSE MIXING FROM THE SUN AND REMAIN UNDER 12
KNOTS. THE COLD FRONT WILL MOVE FROM W TO E EARLY TUESDAY MORNING
FORCING THE WINDS TO TRANSITION FROM A SOUTHERLY FLOW TO A
WEST/NORTHWESTERLY FLOW. LIGHT RAIN SHOWERS WILL ACCOMPANY THIS
FRONT AND CAUSE RESTRICTIONS OF MVFR CIGS AND VISBYS AT KRME...
KSYR... AND KITH THROUGH 15Z TUESDAY MORNING. THE REMAINING TAFS
SITES ARE EXPECTED TO REMAIN VFR AS THE FRONT PASSES WITH LIGHT RAIN
SHOWERS. WINDS TUESDAY AFTERNOON WILL PICK UP CAUSING LINGERING MVFR
CIGS TO LIFT TO VFR.
OUTLOOK...
TUE NGT...VFR.
WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL
NY AFFECTING RME/SYR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN
SHORT TERM...JAB
LONG TERM...
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
718 PM EDT MON OCT 21 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC
TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE
AREA EARLY TUESDAY MORNING. BEHIND THE FRONT EXPECT MUCH COLDER
AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK.
CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT
RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TUESDAY/...
715 PM UPDATE...
NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN
ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN
IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES
THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY
NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT
UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON
TARGET AT THIS TIME.
PREV DISCUSSION BLO...
BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN
CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT
APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION
VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS
IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS
THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH
PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY
ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS
HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING
ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND
FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS
TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH
OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH
SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY
AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS
IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE
CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE
AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN
FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY
OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE
WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS
DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY.
FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY
ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY
UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE
BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE
40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR
FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING
FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN
COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE
OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE
BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS
OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY.
MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT
ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY
WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD
CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES
LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW
ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS
THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS
RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY
MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM
TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE
TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE
SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS
IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING
OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO
PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT
THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO
DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH
SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
CDFNT OVER THE ERN GTLAKES WILL PASS THRU THE BGM CWA VERY LATE
TNGT/EARLY TUE MRNG. VFR CONDITIONS WILL PREVAIL TIL AFTER MDNGT.
XPCT A NARROW BAND OF -SHRA AND ASSCD MVFR CIGS TO ACCOMPANY THE
FNT...AFFECTING CNTRL NY SITES IN THE 09-13Z TIME FRAME. AT
AVP...IT APPEARS THAT CONDITIONS WILL REMAIN VFR EVEN WITH FROPA.
LATER TMRW MRNG...SCT-BKN CIGS SHUD RISE INTO THE VFR CATEGORY.
GUSTY S TO SW WINDS THIS AFTN 15-25 KTS...BECMG SRLY TNGT 5-15
KTS...THEN WRLY POST FROPA 10-20 KTS.
OUTLOOK...
TUE NGT...VFR.
WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL
NY AFFECTING RME/SYR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN
SHORT TERM...JAB
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
316 PM CDT SUN OCT 20 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 316 PM CDT SUN OCT 20 2013
CHALLENGES THROUGH THE PERIOD INCLUDE LOW END PRECIPITATION CHANCES
AND TEMPERATURES. GFS/NAM/ECMWF/GEM IN REASONABLE AGREEMENT AND
WILL FOLLOW AND BLENDED MODEL SOLUTION.
20 UTC SURFACE ANALYSIS SHOWS THE SURFACE LOW SOUTHWEST OF
MINNEAPOLIS AND MOST OF ITS ASSOCIATED PRECIPITATION ACROSS THE MN
ARROWHEAD INTO NORTHWEST WI. A COUPLE SURFACE OBS ACROSS WEST
CENTRAL MN STILL REPORTING LIGHT RAIN...BUT WITH VISIBILITY OF 10
SM...MOST LIKELY JUST SOME LINGERING SPRINKLES. WILL CONTINUE THIS
DRYING TREND INTO THE EARLY EVENING WITH ONLY SOME 20 POPS ACROSS
THE LAKE OF THE WOODS REGION OVERNIGHT AS THE SURFACE LOW PIVOTS
BACK TO THE NORTH AND ITS INVERTED TROUGH PINWHEELS ABOUT THE
INTERNATIONAL BORDER.
THERE IS ABUNDANT CLOUD COVER UPSTREAM...BUT IT IS MORE CELLULAR
IN NATURE...SO IT/S DIFFICULT TO SAY HOW MUCH CLEARING WILL OCCUR
OVERNIGHT...ESPECIALLY WHEN THE RAP 925 HPA RH SHOWS SATURATED
CONDITIONS THROUGH MONDAY MORNING. WILL SHOW SOME CLEARING WEST OF
THE VALLEY BY 12 UTC MONDAY...BUT THIS MAY BE OVERLY OPTIMISTIC.
EITHER WAY...WITH HIGHS THIS AFTERNOON IN THE 30S...NIGHTTIME
LOWS IN THE 20S SEEM REASONABLE.
BEST CHANCE FOR PRECIPITATION MONDAY WILL CONTINUE ACROSS THE LAKE
OF THE WOODS REGION WITH ALL OTHER AREAS DRY. SHOULD SEE A BIT
MORE SUN TO THE SOUTH AND WEST...BUT COLD AIR MASS WILL KEEP
HIGH TEMPERATURES IN THE 30S. NORTH-NORTHWEST WIND WILL PERSIST...
BUT WITH A WEAKENING PRESSURE GRADIENT...SHOULD BE A BIT LOWER
FROM 10 TO 15 MPH.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 316 PM CDT SUN OCT 20 2013
CANADIAN HIGH PRESSURE DIVES SOUTH ACROSS THE NORTHERN PLAINS
TUESDAY AND WEDNESDAY FOR MOSTLY DRY CONDITIONS. HOWEVER...
PERSISTENT CYCLONIC FLOW ALOFT COMBINED WITH HIGHER MID-LEVEL
MOISTURE WILL RESULT IN QUITE A BIT OF CLOUDS. MID-LEVEL THERMAL
RIDGE WILL NUDGE EASTWARD...ALLOWING FOR A LITTLE WARMING EACH
DAY...SO THAT HIGHS BY WEDNESDAY SHOULD APPROACH 40 DEGREES. THIS
IS STILL 10 TO 15 DEGREES BELOW MID-LATE OCTOBER NORMALS.
WED NIGHT-SUNDAY...NORTHWEST FLOW ALOFT THOUGH THE PERIOD. 12Z
MODELS ARE IN GOOD AGREEMENT INITIALLY...BUT QUICKLY DISAGREE WITH A
STRONGER WAVE FRIDAY INTO SUNDAY. THE GFS/GEM ARE MUCH QUICKER AND
FURTHER WEST WITH THIS WAVE THAN THE ECMWF. THE GFS/GEM BRING PRECIP
INTO NORTHWEST MINNESOTA WITH THIS FEATURE...WHILE THE ECMWF IS
BASICALLY DRY THROUGH THE PERIOD. TEMPERATURES WOULD ALSO BE
AFFECTED WITH EXACTLY WHERE THIS WAVE TRACKS. THE BLEND OF MODELS IS
LIKELY THE BEST COURSE OF ACTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 117 PM CDT SUN OCT 20 2013
THE GENERAL TREND WILL BE IMPROVING CONDITIONS THROUGH THE PERIOD.
FOLLOWED THE 15Z RAP FOR GUIDANCE ON TIMING THE IMPROVEMENT. SITES
ALONG AND WEST OF THE VALLEY EXPECTED TO EVENTUALLY BE VFR BY LATER
THIS EVENING...WHILE SITES EAST OF THE VALLEY WILL LIKELY REMAIN
MVFR. GUSTY NORTHERLY WINDS THIS AFTERNOON WILL SUBSIDE A BIT
TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/TG
AVIATION...TG
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
117 PM CDT SUN OCT 20 2013
.UPDATE...
ISSUED AT 117 PM CDT SUN OCT 20 2013
WILL ALLOW THE REMAINING COUNTIES IN THE WINTER WEATHER ADVISORY
TO EXPIRE AT 1 PM CDT. PERIODS OF LIGHT RAIN OR SNOW ARE POSSIBLE
THIS AFTERNOON MAINLY ACROSS SOUTHEAST ND INTO WEST CENTRAL MN...
BUT NOT EXPECTING MUCH IF ANY ADDITIONAL SNOW ACCUMULATION.
VISIBILITIES HAVE RISEN ABOVE A MILE AND SURFACE TEMPERATURES NOW
IN THE MID TO UPPER 30S ARE HELPING PRECIPITATION CHANGE BACK TO
RAIN. SOME SLICK SPOTS ON AREA ROADWAYS STILL POSSIBLE...SO
MOTORISTS SHOULD DRIVE WITH CAUTION.
CLOUDS ARE STARTING TO BREAK ACROSS THE DEVILS LAKE BASIN AND
PORTIONS OF THE FAR NORTHERN VALLEY...BUT WITH LOW CONVECTIVE
TEMPERATURES AND CYCLONIC FLOW ALOFT...THINK THERE SHOULD BE A
FAIR AMOUNT OF CU TO FILL BACK-IN. NORTHERLY WINDS NOW INCREASING
TO NEAR 20 KTS ALONG AND WEST OF THE RED RIVER VALLEY AND THIS IS
HANDLED WELL IN CURRENT GRIDS. REST OF THE FORECAST IN GOOD SHAPE
WITH NO CHANGES AT THIS TIME.
UPDATE ISSUED AT 1023 AM CDT SUN OCT 20 2013
MAIN QUESTION THIS MORNING IS WHAT TO DO WITH ONGOING WINTER
WEATHER ADVISORY. AREA WEBCAMS SHOW WET ROADWAYS WITH LITTLE TO
NO SNOW ACCUMULATION. THE MAJORITY OF MORNING SNOW REPORTS HAVE
BEEN A HALF INCH OR LESS ON GRASSY SURFACES AND DO NOT ANTICIPATE
MUCH MORE ACCUMULATION WITH CURRENT VISIBILITIES ABOVE ONE MILE.
THE EXCEPTION BEING IN THE PARK RAPIDS/WADENA/DETROIT LAKES AREA
WHERE SOME ACCUMULATION ON ROADWAYS IS VISIBLE ON MNDOT WEBCAMS.
RAP/HRRR/LOCAL WRF SUGGEST THESE AREAS STAND THE BEST CHANCE OF
ADDITIONAL SNOW THROUGH THE MORNING AS THE SURFACE LOW RAPIDLY
MOVES INTO SOUTH-CENTRAL MN. ANOTHER 1-2 INCHES IS NOT OUT OF THE
QUESTION. ALL THIS SAID...WILL CANCEL THE ADVISORY ACROSS ALL OF
EASTERN ND AND MOST OF NORTHWEST MN...LEAVING IT INTACT FOR AREAS
SOUTH AND EAST OF A LINE FROM FERGUS FALLS TO MAHNOMEN TO JUST
SOUTH OF BEMIDJI. ROADS MAY STILL BE SLICK...HOWEVER...WITH
SURFACE TEMPERATURES AT OR JUST ABOVE FREEZING. ADJUSTED POPS TO
FOLLOW THIS THINKING...BUT REST OF FORECAST IS IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
UPDATE ISSUED AT 635 AM CDT SUN OCT 20 2013
THE CHALLENGE FOR THIS UPDATE WILL BE WINTER WEATHER HEADLINES.
THIS VERY CHALLENGING EVENT CONTINUES TO UNFOLD...WITH SNOW NOW
OCCURRING AT THE OFFICE HERE AND SNOW TO THE NORTH OF US. IT IS
STILL RAIN IN THE FARGO AREA...BUT OBS JUST EAST OF FARGO INTO THE
PKD/BJI/FSE AREA ARE ALL SNOW. OVER THE NEXT FEW HOURS...COLDER
AIR SHOULD CHANGE RAIN TO SNOW IN THE FARGO AREA. WE HAVE HAD A
REPORT OF AROUND AN INCH IN NE ND...WITH TEMPS AROUND FREEZING.
NOT EXPECTING TOO MUCH SNOW ACCUMULATION FOR MOST OF ND
COUNTIES WITH WARM GROUND TEMPS AND FAIRLY WEAK SNOW RATES...BUT
AN INCH OF SNOW AND SOME ICY ROADS POSSIBLE THIS MORNING. EXPECT
THE 1-2 INCH AMOUNTS IN THE HIGHER TERRAIN AWAY FROM THE VALLEY
FLOOR IN ND AND MN. THERE SHOULD BE A BETTER CHANCE AT A FEW INCHES
OF SNOW FROM MAHNOMEN TO PKD...AND THE ADVY LOOKS GOOD HERE. CAN/T
EVEN RULE OUT AN INCH OR SO FROM FSE EAST TO BJI...BUT FOR NOW
WON/T EXPAND ADVISORY BUT MONITOR. THEREFORE...FOR NOW WON/T
ADJUST THE ADVISORY AND WE WILL CONTINUE TO MONITOR THROUGH THE
MORNING FOR ANY NEEDED CHANGES.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM CDT SUN OCT 20 2013
THE MAIN CHALLENGE THIS MORNING WILL BE CURRENT HEADLINES AND
PRECIP FOR THE REST OF TONIGHT AND SUNDAY. MODELS HAVE COME INTO
BETTER AGREEMENT WITH THE OVERALL TRACK OF THE QPF BAND...BUT
STILL SOME DIFFERENCES IN THERMAL FIELDS EVEN WITH MESOSCALE
MODELS. THEREFORE...STILL SOME QUESTIONS AS TO WHO ACTUALLY GETS
SOME ACCUMULATION.
FOR THE NEAR TERM...GETTING JUST PLAIN RAIN AT THE OFFICE AND THIS
WILL LIMIT ANY SNOW ACCUMS AT LEAST INITIALLY. THERE IS SOME MINOR
ACCUMS LIKELY NEAR LANGDON SINCE THEY HAVE BEEN 32 FOR THE PAST
FEW HOURS AND VSBYS BELOW 3SM. ALSO...WHEN LOOKING AT DUAL POL
DATA...IT SEEMS THE CHANGEOVER TO SNOW AROUND AND NORTH OF GFK
SHOULD OCCUR BY 9Z. WE WILL MONITOR CLOSELY THROUGH THE MORNING
HOURS...AND MAY NEED TO CANCEL PORTIONS OF THE ADVISORY IF SNOW
ACCUMS DO NOT OCCUR. TEMPS WILL STILL FALL BELOW FREEZING THROUGH
THE PRE DAWN HOURS IN THE NORTHERN VALLEY...AND SOME SLICK SPOTS
ON ROADS ARE POSSIBLE.
EARLY THIS MORNING AND TODAY...EXPECT MOST OF THE PRECIPITATION
TO HAVE CHANGED OVER TO SNOW BY 12Z...EXCEPT PERHAPS IN THE FAR
SOUTH WHERE MAINLY RAIN SHOULD FALL. THERE SHOULD BE A TIME WHERE
SOME SNOW ACCUMULATES MAINLY NORTH OF A DEVILS LAKE TO FARGO TO
PARK RAPIDS LINE FROM AROUND 10Z-15Z. THERE COULD BE A FEW REPORTS
OF AN INCH...PERHAPS 2...BUT WITH WARM BOUNDARY LAYER TEMPS
LIMITING SNOW FALL INITIALLY...ACCUMS SHOULD BE LIGHT. WE WILL
CONTINUE TO MONITOR ANY EXPECTED CHANGES IN THIS THINKING...SINCE
ELEVATION WILL PLAY A ROLE IN SNOW ACCUMS AS THE BAND PROGRESSES
INTO MN EARLY THIS MORNING. THERE IS ALSO AN AREA IN EASTERN POLK
COUNTY INTO SOUTHERN CLEARWATER/BELTRAMI COUNTIES WHERE TEMPS ARE
BELOW FREEZING. IF RAIN OCCURS HERE INITIALLY...COULD BE SOME
ICING...ALTHOUGH LOOKING AT RWIS SITES SHOWS ROAD SFC TEMPS ARE IN
THE MID 30S...SO FOR NOW WON/T EXTEND ADVISORY EAST BUT WILL
MONITOR. NORTHERLY WINDS WILL INCREASE BEHIND THE FRONT AND GUST
OVER 30 MPH IN THE VALLEY...AND IT WILL BE A BLUSTERY DAY. AFTER
18Z...EXPECT MORE OF A RAIN/SNOW MIX IN THE EAST AND ANY POTENTIAL
FOR ACCUMS SHOULD END.
FOR TONIGHT AND MONDAY...EXPECT THE POTENTIAL FOR SOME WRAPAROUND
LIGHT SNOWS MAINLY IN THE EAST. TEMPS WILL CONTINUE TO BE VERY
COLD...WITH WINDS FAIRLY STRONG TONIGHT AND MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 AM CDT SUN OCT 20 2013
FOR MONDAY NIGHT THROUGH TUE NIGHT...IT SHOULD BE MAINLY DRY WITH
PERHAPS A FEW LIGHT SNOW SHOWERS IN THE FAR NORTHEAST MON NIGHT.
IT WILL REMAIN COLD WITH TEMPS WELL BELOW NORMAL.
FOR WEDNESDAY-SATURDAY...LITTLE CHANGE IN THE LONGWAVE PATTERN IS
ANTICIPATED THROUGH NEXT WEEKEND. WITH STRONG POSITIVE 500 MB HEIGHT
ANOMALIES INTO THE NORTHEAST PACIFIC AND TROUGHING INTO THE EASTERN
CONUS...THE NORTHERN PLAINS WILL REMAIN UNDER CHILLY NORTHWEST FLOW
ALOFT. SHORTWAVE TROUGHS RIDING THE PERIPHERY OF THE WESTERN CONUS
RIDGE WILL DIVE SOUTHWARD...ALLOWING REINFORCING SURGES OF COOL AIR
TO SPILL INTO THE REGION...WITH DAY-TO-DAY TEMP VARIATIONS DEPENDENT ON
THE TIMING OF THESE WAVES. HOWEVER...TEMPS LOOK TO REMAIN PRIMARILY
BELOW NORMAL. NO SIGNIFICANT PRECIPITATION IS EXPECTED...WITH ONLY
LOW CHANCES FOR SOME LIGHT RAIN/SNOW ASSOCIATED WITH ANY PROGRESSIVE
SHORTWAVE TROUGHS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 117 PM CDT SUN OCT 20 2013
THE GENERAL TREND WILL BE IMPROVING CONDITIONS THROUGH THE PERIOD.
FOLLOWED THE 15Z RAP FOR GUIDANCE ON TIMING THE IMPROVEMENT. SITES
ALONG AND WEST OF THE VALLEY EXPECTED TO EVENTUALLY BE VFR BY LATER
THIS EVENING...WHILE SITES EAST OF THE VALLEY WILL LIKELY REMAIN
MVFR. GUSTY NORTHERLY WINDS THIS AFTERNOON WILL SUBSIDE A BIT
TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
815 PM EDT MON OCT 21 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT. LOW PRESSURE AT THE
SURFACE WILL CROSS FROM THE UPPER MIDWEST EAST THROUGH THE OHIO
VALLEY ON TUESDAY AND TUESDAY NIGHT AS IT FOLLOWS A STRONG UPPER
LEVEL TROUGH. THE COLDEST AIR OF THE SEASON WILL BE FOUND BEHIND
THESE SYSTEMS AS HIGH PRESSURE IN THE MIDWEST HELPS USHER IN
NORTHERLY WINDS TO THE OHIO VALLEY THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
COLD FRONT HAVE MOVED INTO THE NORTHWEST COUNTIES AND WILL PUSH
EAST OF THE FORECAST AREA BY AROUND 06Z. A BAND OF SHOWERS IS
OCCURRING IN THE WAKE OF THE FRONT BUT THUS FAR ONLY AFFECTING THE
NORTHERN PART OF THE AREA. HOWEVER RECENT HRRR AND RAP RUNS
SUGGEST THAT SHOWERS WILL DEVELOP FURTHER SOUTH LATE IN THE
EVENING AND THEN PROGRESS EAST CLEARING THE REGION BY DAYBREAK.
CLOUDS WILL DECREASE FROM NORTHWEST TO SOUTHEAST LATE AT NIGHT AND
TEMPERATURES WILL BE ABLE TO DROP INTO THE 30S IN ALL BUT THE
SOUTHEAST. IT WILL GET COLD ENOUGH FOR SOME FROST IN THE NORTHWEST
PART OF THE AREA. BUT THERE IS SOME QUESTION WHETHER WINDS WILL
GET LIGHT ENOUGH FOR THIS TO HAPPEN. SO HAVE STAYED WITH PATCHY
WORDING. NO CHANGES TO THE FROST ADVISORY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
COOLER AIR WILL HAVE A CHANCE TO WARM UP ON TUESDAY BUT THAT WILL
BE THE END OF IT AS TUESDAY NIGHT WILL SEE A SURFACE LOW TRACK
EAST THROUGH THE OHIO VALLEY UNDERNEATH A STRONG UPPER TROUGH. THE
TWO WILL PROVIDE ENOUGH WIDESPREAD LIFT TO CREATE SHOWERS
OVERNIGHT AND WITH THE COLD AIR BEING USHERED IN BEHIND THEM...THE
SHOWERS COULD MIX WITH SNOW BEFORE ENDING EARLY WEDNESDAY.
READINGS TUESDAY WILL STRUGGLE TO REACH MUCH PAST 50 DEGREES WHILE
WEDNESDAY WILL BE ENTRENCHED IN THE 40S WITH A TYPICAL NW-SE
GRADIENT FOUND WITH THE COOLEST AIR BEING USHERED IN ON NORTHWEST
WINDS ALOFT AND WESTERLY SURFACE WINDS.
A SECONDARY WAVE OF ENERGY IN THE UPPER MEAN TROUGH WILL CROSS
ESE THROUGH THE REGION WEDNESDAY NIGHT AND COULD RESULT IN
ADDITIONAL SHOWERS OF A MIXED VARIETY.
REGARDLESS OF THE INCREASED POTENTIAL FOR SEEING SNOW IN THE NEXT
FEW DAYS...THERE WILL NOT BE ANY ACCUMULATION TO WORRY ABOUT AS
SURFACE TEMPERATURES WILL BE ABOVE FREEZING OUTSIDE OF THE EARLY
MORNING/DAYBREAK HOURS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
PERIOD BEGINS WITH THE H5 TROF SET UP OVER THE ERN U.S. AND NW
FLOW WORKING ACROSS THE GREAT LAKES. AS EXPECTED IN THE FAST FLOW
THE EXTENDED MODELS ARE SLIGHTLY DIFFERENT WITH STRENGTH AND
PLACEMENT. TRIED TO GO WITH A CONSENSUS FORECAST. SO WENT WITH
SLIGHTLY HIGHER POPS ACROSS THE SRN COUNTIES AT THE BEGINNING OF
THE PERIOD...WITH SLIGHTLY LOWER POPS TO THE N. THERE SHOULD BE
SOME DAYTIME REDEVELOP ON THURSDAY AS COLD AIR ALOFT INCREASES THE
INSTABILITY...BEFORE THE ENERGY WORKS E OF THE FA. DUE TO THE SUB
FREEZING COLD AIR AT H8...SOME SNOW COULD MIX ON THURSDAY.
SFC HIGH PRESSURE BUILDS UP THE OHIO VALLEY THURSDAY NIGHT INTO
FRIDAY...BRINGING AN END TO THE COLD AIR PCPN AND SUNNIER SKIES.
MODELS DROP A WEAK CDFNT DOWN THRU THE LAKES SATURDAY INTO
SATURDAY NIGHT. MOISTURE LOOKS VERY LIMITED. CARRIED A 20 POP WITH
THE FROPA IN OHIO IN CASE A STRAY SHOWER DEVELOPS. HIGH PRESSURE
BUILDS BACK IN FOR SUNDAY AND MONDAY.
AS FOR TEMPERATURES...THE MUCH BELOW NORMAL TEMPERATURES WILL
LINGER INTO THURSDAY WITH HIGHS IN THE MID TO UPPER 40S...BUT ARE
EXPECTED TO WORK INTO THE 50S FOR THE WEEKEND. SUB FREEZING
TEMPERATURES ARE POSSIBLE THURSDAY AND FRIDAY NIGHTS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
COLD FRONT WILL MOVE THROUGH ALL OF THE TERMINALS EARLY IN THE TAF
PERIOD. SHOWERS CAN BE EXPECTED FOR A FEW HOURS AFTER FRONTAL
PASSAGE EXCEPT FOR PERHAPS IN THE CINCINNATI AREA. SHOWERS WILL BE
LIGHT AND SHOULD NOT AFFECT VISIBILITY BUT THERE COULD BE A BRIEF
PERIOD OF MVFR CEILINGS. CLOUDS WILL CLEAR BEFORE 12Z AND
CONDITIONS WILL REMAIN VFR. SOME HIGH AND MID CLOUDS WILL MOVE
BACK IN LATE. HIGH PRESSURE QUICKLY MOVING ACROSS THE REGION WILL
ALLOW WINDS TO BACK DURING THE DAY.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE TUESDAY NIGHT
AND WEDNESDAY. WINDS GUSTING UP TO 30 KT WILL BE POSSIBLE ON
WEDNESDAY AS WELL.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FROST ADVISORY FROM 4 AM TO 9 AM EDT TUESDAY FOR OHZ026-034-
035-042-043.
KY...NONE.
IN...FROST ADVISORY FROM 4 AM TO 9 AM EDT TUESDAY FOR INZ050-058.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
204 AM EDT SUN OCT 20 2013
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION THIS EVENING FOLLOWED
BY A VISIT FROM HIGH PRESSURE ON SUNDAY AND MONDAY. THE PATTERN
WILL TURN NOTICEABLY COOLER AND UNSETTLED NEXT WEEK AS AN UPPER
TROUGH ESTABLISHES ITSELF OVER THE EASTERN UNITED STATES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
REGIONAL RADAR LOOP AT 02Z SHOWS A DWINDLING LINE OF SHOWERS
ASSOC WITH COLD FRONT ENTERING THE SUSQ VALLEY. DESPITE A DECENT
AMT OF MOISTURE POOLING AHEAD OF FRONT...UPPER LVL SHORTWAVE AND
ASSOC LG SCALE FORCING IS LIFTING NORTH OF THE BORDER...SO LITTLE
CHC OF MORE THAN AN ISOLD SHOWER AS FRONT PUSHES THRU THE EASTERN
COUNTIES BTWN 02Z-04Z. LATEST RAP OUTPUT INDICATES CDFRONT WILL
CLEAR THE EASTERNMOST COUNTIES /SCHUYLKILL AND LANCASTER/ BY
MIDNIGHT. BEHIND FRONT...ONLY REMAINING PRECIP WILL BE IN THE
FORM OF LAKE EFFECT RAIN SHOWERS COMING OFF OF LK ERIE. CURRENT
RADAR TRENDS AND RAP/NAM OUTPUT SUGGEST SHOWERS ACROSS
WARREN/MCKEAN COS WILL SHIFT NORTH OF THE BORDER AFTER 06Z...AS
BLYR FLOW BACKS TO THE WSW.
CLEARING SKIES ALREADY DEVELOPING EAST OF THE MTNS AT 02Z AND
EXPECT THAT TREND TO CONTINUE OVERNIGHT...AS DRIER WEST FLOW
OVERSPREADS CENTRAL PA. STRATOCU MAY LINGER FOR A WHILE ACROSS
THE LAUREL HIGHLANDS...BUT EXPECT CLEARING EVEN THERE LATE
TONIGHT. THE INITIALLY GUSTY WEST WINDS SHOULD SLACKEN LATE
TONIGHT...AS HIGH PRES RIDGE BUILDS IN FROM THE OHIO VALLEY. BLEND
OF LATEST LAMP AND RAP GUIDANCE SUGGEST TEMPS WILL BOTTOM OUT IN
THE M30S ACROSS THE ALLEGHENY PLATEAU...TO THE L40S OVR THE SUSQ
VALLEY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
HIGH PRESSURE WILL PASS JUST SOUTH OF THE STATE ON SUNDAY...PROVIDING
THE AREA WITH SEASONABLY COOL AND DRY WX. ALTHOUGH A WSW BLYR FLOW
WILL KEEP LINGERING LAKE EFFECT ACTIVITY NORTH OF THE
BORDER...COLD TEMPS ALOFT SHOULD YIELD A GOOD AMT OF DIURNAL
STRATOCU ACROSS THE NW MTNS. WIND WILL INCREASE A BIT FROM A MORNING
LULL...AS THE ATMOS MIXES. MDL SOUNDINGS SUPPORT AFTN GUSTS BTWN
20-25KTS ACROSS THE NW MTNS...AND BTWN 10-15KTS ACROSS THE LOWER
SUSQ VALLEY.
HIGH TEMPS UNDER THE RATHER HOMOGENEOUS 0C-M2C 8H TEMPS WILL BE
ALMOST ENTIRELY DEPENDENT ON ELEVATION AND DOWNSLOPE WARMING.
MAXES SHOULD BE CLOSE TO 50F IN THE NW MTNS AND NEAR 60F IN THE
VALLEYS/LOWER ELEVS OF THE SUSQ VALLEY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
CENTRAL PA WILL BE ON NORTHERN EDGE OF ERODING HIGH PRESSURE RIDGE
SUN NIGHT INTO MON...WITH A WARM FRONT LIFTING THROUGH OHIO VALLEY
AND SKIRTING W PA. THIS WILL KEEP WEATHER FAIR AND MILD...WITH
HIGHS MONDAY SLIPPING INTO THE 60S /ABOUT 4-8F ABOVE NORMAL/.
THINGS START TO GO DOWNHILL MONDAY NIGHT AS NEW ENERGY STARTS
DIVING OUT OF SOUTHERN CANADA ON THE WAY TO CARVING OUT A LARGE
SCALE PERSISTENT TROF OVER THE EASTERN U.S. A BUILDING RIDGE OVER
THE WEST COAST WILL HELP DEEPEN AN ADVANCING LOW...WHICH WILL
DELIVER A STEADY FEED OF INCREASINGLY MORE CHILLY AIR ACROSS THE
UPPER MIDWEST NEXT WEEK. THIS COLD AIR WILL PROPAGATE INTO THE
LOWER LAKES AND LOCAL AREA IN THE WAKE OF A COLD FRONTAL BOUNDARY
PROGGED FOR TUESDAY...AND REINFORCED BY SECONDARY TROUGH ON
WEDNESDAY /AS ANOTHER LOW FORMS ALONG THE BOUNDARY AND SLIDES
ACROSS MID ATLANTIC STATES JUST TO OUR SOUTH BEFORE SLIDING OFF
THE COAST OF NEW ENGLAND/.
SOME DIFFERENCES CONTINUE IN MODEL SOLUTIONS STARTING AROUND
WEDNESDAY WHEN THE ECMWF BRINGS A STRONG SHORTWAVE OUT OF THE
OHIO VALLEY. THE OPERATIONAL GFS AND THE GEFS /PREVIOUSLY WITH A
FLATTER TROUGH/ ARE COMING MORE IN LINE WITH THE EC...WHICH WILL
INCREASE OUR POP CHANCES FOR WED WITH A STEADY LIGHT RAIN POSS.
AFTER THAT...CYCLONIC FLOW WILL CONTINUE TO ALLOW INCREASINGLY
COOLER AIR TO FILTER IN ON NW FLOW. PLENTY OF COLD ADVECTION
STRATOCU AND LAKE/OROGRAPHIC SHOWERS LOOKING LIKELY IN THE HIGHER
WESTERN TERRAIN MID/LATE WEEK...WITH DOWNSLOPE COMPONENT TO WINDS
KEEPING PRECIP AT A MIN FOR THE SE. LOW LEVEL TEMPS GET COLD
ENOUGH /850MB TEMPS DIP BELOW 0C/ THAT LIGHT SHOWERS COULD BE
MIXED WITH WET SNOW DURING THE CHILLIEST PART OF THE DAY AND
OVERNIGHT.
HIGH PRESSURE BUILDS IN LOW LEVELS FOR THE WEEKEND...BRINGING
QUITE CHILLY MORNING TEMPS. BUT AN OVERALL MORE SETTLED WEATHER
PATTERN. REINFORCING SHOT OF COLDER AIR POSS EARLY NEXT WEEK.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MOST OF THE SHOWERS OFF LAKE ERIE WILL BE NORTH OF OUR AREA...
BUT CLOUDS WILL LINGER INTO LATE MORNING OR EARLY AFT...GIVEN
THE STRONG FLOW OF COLD AIR OVER THE LAKE. THE AIRMASS IS COLD
ENOUGH TO RESLULT IN RADAR RETURNS OF ALMOST 50 DBZ ALONG THE
LAKE ERIE SHORELINE.
ANYWAY...AS WINDS SHIFT MORE TO THE SW THIS AFTERNOON AND
WEAKEN...CLOUDS WILL THIN OUT.
CLOUDS INCREASE ACROSS THE AREA BY MONDAY MORNING...AS ANOTHER
LOW PRESSURE SYSTEM LIFTS NE ACROSS THE LOWER LAKES REGION.
SOME SHOWERS WILL BE POSSIBLE LATER MONDAY AFT INTO TUE...AS
THE NEXT COLD FRONT MOVES ACROSS THE AREA.
OUTLOOK...
TUE...FROPA. MVFR/IFR POSS DUE TO SHOWERS/CLOUDS...ESP NW.
WED...MVFR POSS IN SHRA...ESP NW.
THURS...BREEZY...MVFR CLOUDS/SHRA N/W.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...RXR
AVIATION...JUNG/MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
813 PM CDT MON OCT 21 2013
.UPDATE...
COLD FRONT SHOWING UP WELL ON RADAR IMAGERY THIS EVENING AND IS
CURRENTLY MOVING THROUGH MEMPHIS AND HAS JUST ENTERED NORTHWEST
STEWART COUNTY. POST FRONTAL SHOWERS CONTINUE SPREADING EASTWARD
ACROSS WEST TENNESSEE AND WEST KENTUCKY...AND THIS ACTIVITY WILL
MOVE INTO NORTHWEST ZONES OVER THE NEXT FEW HOURS. HAVE ADJUSTED
GRIDS/ZONES BASED ON LATEST OBS AND TRENDS AND KEPT HIGHEST POPS
OVER THE NORTH. RAINFALL AMOUNTS ARE STILL EXPECTED TO BE LIGHT
AND GENERALLY LESS THAN A TENTH OF AN INCH.
OTHERWISE...LATEST MAV/MET MOS CONTINUES TO SHOW A CHILLY WEEK
AHEAD WITH LOWS BACK INTO THE 30S FOR MOST OF THE MID STATE FROM
WEDNESDAY MORNING ON...WITH HIGHS ONLY IN THE 50S AND EVEN 40S ON
THE PLATEAU. 18Z GUIDANCE ALSO CONTINUES TO SUGGEST A LIGHT FREEZE
FOR MUCH OF THE CWA FRIDAY MORNING AND A POTENTIAL HARD FREEZE
SATURDAY MORNING AS A COLD 1028MB SURFACE HIGH SETTLES DIRECTLY
OVER THE REGION.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 634 PM CDT MON OCT 21 2013/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
ONE OF MULTIPLE COLD FRONTS THAT WILL PASS THROUGH TN THIS WEEK IS
CREEPING UP ON US. THE FRONT IS WEAK...THE RAINS ARE LIGHT AND THE
MOISTURE ISN`T VERY DEEP. THIS SHOULD HELP TO KEEP US VFR
THROUGHOUT THIS FROPA. -RA SHOULD BE NEAR KCKV BY 06 AND KBNA BY
08Z...AND I QUESTION WHETHER OR NOT THE RAIN WILL EVEN OCCUR IN
KCSV. WIND SHIFT SHOULD COME SHORTLY BEFORE THE RAINS...SO KEEP
THAT IN MIND. RAINS SHOULD END FOR TERMINALS BY MID-MORNING AND
RETURN TO JUST HIGH CLOUDS BY THE AFTERNOON.
PREV DISCUSSION... /ISSUED 317 PM CDT MON OCT 21 2013/
SHORT TERM...SATELLITE PICS SHOWED CLOUDS INCREASING OVER SOUTHERN
MIDDLE TENNESSEE THIS AFTERNOON, AS WELL AS OVER THE EXTREME
NORTHWEST. BIG BULGE OF 300-500MB MOISTURE LIFTING NORTHWARD FROM
GULF COASTAL REGION, AHEAD OF MISSISSIPPI VALLEY SHORTWAVE, WAS
RESPONSIBLE FOR THE INCREASE IN CLOUDS OVER THE SOUTH. MEANWHILE,
A BAND OF INCREASED 850-700MB MOISTURE, IMMEDIATELY AHEAD OF THE
SHORTWAVE WAS PRODUCING THE INCREASED CLOUDS OVER THE EXTREME NORTHWEST.
SURFACE COLD FRONT, THAT WAS PUSHING INTO THE MISSOURI BOOTHEEL AT
MID-AFTERNOON, WAS CREATING A BAND OF SHOWERS, EXTENDING FROM
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS UP ACROSS SOUTHERN PARTS
OF MISSOURI. THIS COLD AND BAND OF RAIN IS EXPECTED TO PUSH EASTWARD
OVERNIGHT INTO MIDDLE TENNESSEE, AND BOTH THE HRRR BRINGS THIS
BAND OF LIGHT RAIN INTO AT LEAST NORTHWESTERN AND NORTH-CENTRAL
PARTS OF OUR FA BY 12Z TUE.
EVEN THOUGH PRECIP TOTALS WILL BE LIGHT WITH THIS NEXT COLD FRONT,
BELIEVE AN INCREASE TO "LIKELY POPS" IS WARRANTED OVER MOST
NORTHERN AREAS TONIGHT AND TUESDAY. WILL GO WITH A CHANCE OF SHOWERS
ELSEWHERE. EXPECT FRONT TO BE NEAR A LAFAYETTE-NASHVILLE-WAYNESBORO
LINE AT 06Z AND THEN PUSH TO THE CUMBERLAND PLATEAY BY 12-14Z.
EXPECT POST-FRONTAL SHOWERS TO END OVER EASTERN AREAS BY 18Z TUE.
SURFACE DEW POINTS DON`T DRY OUT MUCH UNTIL PASSAGE OF ANOTHER COLD
FRONT TUESDAY NIGHT...WHICH WILL SEND DEW POINTS TUMBLING INTO THE
UPPER 20S BY WEDNESDAY AFTERNOON. THERE MAY BE A FEW LIGHT SHOWERS
OVER NORTH-CENTRAL AND NORTHEASTERN PARTS OF THE MID STATE TUESDAY
NIGHT AND WEDNESDAY MORNING AS THIS FRONT PASSES THROUGH. HIGHS ON
WEDNESDAY AREN`T EXPECTED TO EVEN GET OUT OF THE 50S!
STILL LOOKS THE COLD AND DRY CANADIAN AIR MASS THAT COMES IN
WEDNESDAY, WILL KEEP DEW POINTS LOW ENOUGH TO PRODUCE THE
LIKELIHOOD FOR SOME FROST AND FREEZING TEMPERATURES OVER MUCH OF
THE MID STATE DURING LATE WEEK...ESPECIALLY DURING THE EARLY
MORNING HOURS ON FRIDAY AND SATURDAY. A HARD FREEZE (I.E., TEMPS
OF AOB 27 DEGS) MAY EVEN OCCUR ALONG THE CUMBERLAND PLATEAU
SATURDAY MORNING. NASHVILLE MAY EVEN FLIRT WITH THE 32 DEG MARK
THAT SAME MORNING.
LONG TERM...LOOKS LIKE OUR CHILLY WEATHER PATTERN MAY RELAX JUST
A BIT EARLY NEXT WEEK, WITH UPPER FLOW BECOMING A BIT MORE ZONAL
AND AFTERNOON HIGHS PERHAPS STARTING TO FLIRT WITH THE 70 DEG MARK
OVER SOME SOUTHERN AND WESTERN COUNTIES BY NEXT MONDAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
634 PM CDT MON OCT 21 2013
.UPDATE...FOR 00Z AVIATION.
&&
.AVIATION...00Z TAF DISCUSSION.
ONE OF MULTIPLE COLD FRONTS THAT WILL PASS THROUGH TN THIS WEEK IS
CREEPING UP ON US. THE FRONT IS WEAK...THE RAINS ARE LIGHT AND THE
MOISTURE ISN`T VERY DEEP. THIS SHOULD HELP TO KEEP US VFR
THROUGHOUT THIS FROPA. -RA SHOULD BE NEAR KCKV BY 06 AND KBNA BY
08Z...AND I QUESTION WHETHER OR NOT THE RAIN WILL EVEN OCCUR IN
KCSV. WIND SHIFT SHOULD COME SHORTLY BEFORE THE RAINS...SO KEEP
THAT IN MIND. RAINS SHOULD END FOR TERMINALS BY MID-MORNING AND
RETURN TO JUST HIGH CLOUDS BY THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 317 PM CDT MON OCT 21 2013/
SHORT TERM...SATELLITE PICS SHOWED CLOUDS INCREASING OVER SOUTHERN
MIDDLE TENNESSEE THIS AFTERNOON, AS WELL AS OVER THE EXTREME
NORTHWEST. BIG BULGE OF 300-500MB MOISTURE LIFTING NORTHWARD FROM
GULF COASTAL REGION, AHEAD OF MISSISSIPPI VALLEY SHORTWAVE, WAS
RESPONSIBLE FOR THE INCREASE IN CLOUDS OVER THE SOUTH. MEANWHILE,
A BAND OF INCREASED 850-700MB MOISTURE, IMMEDIATELY AHEAD OF THE
SHORTWAVE WAS PRODUCING THE INCREASED CLOUDS OVER THE EXTREME NORTHWEST.
SURFACE COLD FRONT, THAT WAS PUSHING INTO THE MISSOURI BOOTHEEL AT
MID-AFTERNOON, WAS CREATING A BAND OF SHOWERS, EXTENDING FROM
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS UP ACROSS SOUTHERN PARTS
OF MISSOURI. THIS COLD AND BAND OF RAIN IS EXPECTED TO PUSH EASTWARD
OVERNIGHT INTO MIDDLE TENNESSEE, AND BOTH THE HRRR BRINGS THIS
BAND OF LIGHT RAIN INTO AT LEAST NORTHWESTERN AND NORTH-CENTRAL
PARTS OF OUR FA BY 12Z TUE.
EVEN THOUGH PRECIP TOTALS WILL BE LIGHT WITH THIS NEXT COLD FRONT,
BELIEVE AN INCREASE TO "LIKELY POPS" IS WARRANTED OVER MOST
NORTHERN AREAS TONIGHT AND TUESDAY. WILL GO WITH A CHANCE OF SHOWERS
ELSEWHERE. EXPECT FRONT TO BE NEAR A LAFAYETTE-NASHVILLE-WAYNESBORO
LINE AT 06Z AND THEN PUSH TO THE CUMBERLAND PLATEAY BY 12-14Z.
EXPECT POST-FRONTAL SHOWERS TO END OVER EASTERN AREAS BY 18Z TUE.
SURFACE DEW POINTS DON`T DRY OUT MUCH UNTIL PASSAGE OF ANOTHER COLD
FRONT TUESDAY NIGHT...WHICH WILL SEND DEW POINTS TUMBLING INTO THE
UPPER 20S BY WEDNESDAY AFTERNOON. THERE MAY BE A FEW LIGHT SHOWERS
OVER NORTH-CENTRAL AND NORTHEASTERN PARTS OF THE MID STATE TUESDAY
NIGHT AND WEDNESDAY MORNING AS THIS FRONT PASSES THROUGH. HIGHS ON
WEDNESDAY AREN`T EXPECTED TO EVEN GET OUT OF THE 50S!
STILL LOOKS THE COLD AND DRY CANADIAN AIR MASS THAT COMES IN
WEDNESDAY, WILL KEEP DEW POINTS LOW ENOUGH TO PRODUCE THE
LIKELIHOOD FOR SOME FROST AND FREEZING TEMPERATURES OVER MUCH OF
THE MID STATE DURING LATE WEEK...ESPECIALLY DURING THE EARLY
MORNING HOURS ON FRIDAY AND SATURDAY. A HARD FREEZE (I.E., TEMPS
OF AOB 27 DEGS) MAY EVEN OCCUR ALONG THE CUMBERLAND PLATEAU
SATURDAY MORNING. NASHVILLE MAY EVEN FLIRT WITH THE 32 DEG MARK
THAT SAME MORNING.
LONG TERM...LOOKS LIKE OUR CHILLY WEATHER PATTERN MAY RELAX JUST
A BIT EARLY NEXT WEEK, WITH UPPER FLOW BECOMING A BIT MORE ZONAL
AND AFTERNOON HIGHS PERHAPS STARTING TO FLIRT WITH THE 70 DEG MARK
OVER SOME SOUTHERN AND WESTERN COUNTIES BY NEXT MONDAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
940 PM CDT MON OCT 21 2013
.UPDATE...
ISSUED AT 938 PM CDT MON OCT 21 2013
HAVE BEEN FOLLOWING THE TRENDS OF THE HRRR AND RAP ALL EVENING
AND THE 22.00Z NAM HAS NOW COME IN AS WELL...ALL WITH THE SNOW
STRIPE FURTHER SOUTH IN IA BY 1-2 COUNTIES. HAVE TRENDED THE
FORECAST THAT WAY WITH REDUCED PRECIPITATION CHANCES...AND LESS
SNOWFALL /NOW ABOUT 0.5 INCHES VERSUS 1 INCH/ IN FAR SOUTH. WITH
CLEAR SKIES AND SOME LOW-LEVEL RIDGING AND LIGHT WIND...HAVE ALSO COOLED
LOW TEMPERATURES ACROSS THE SOUTH TOO.
FORECAST SHOULD BE UP TO THE WEB SITE AND IN PRODUCTS SHORTLY.
UPDATE ISSUED AT 702 PM CDT MON OCT 21 2013
HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO
IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING
THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE
A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY
OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE
SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST
AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z
NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO
AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF
SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z
GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE
BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH
BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN
TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA
CROSSE FORECAST AREA.
FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT
THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING
WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING
AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS
BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND
WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR
AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA.
CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS
NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER
EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF
THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE
STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY
LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER
NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED
TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS
AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME
CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT
SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT.
THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL
DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO
TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY
THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST
SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z
MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS
SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST
IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW
THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE
COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE
SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH
OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD
FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY
MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION.
TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY
AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C
BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN
THE AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE
WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE
NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING
ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH
THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA.
THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN
THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY
THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO
HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN
THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING
THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM
ENOUGH TO CAUSE THAT CHANGE OVER.
THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB
TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW
LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS
DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE
DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A
TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS
TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS
OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE
50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN.
THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD
TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN
ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY
NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A
WIDESPREAD RAIN EVENT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 700 PM CDT MON OCT 21 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A CLEAR PERIOD THIS
EVENING WILL BE FOLLOWED BY INCREASING MID-LEVEL CLOUDS NORTH OF A
WEATHER SYSTEM MOVING FAST OUT OF THE DAKOTAS TO IL. THIS WILL
CAUSE AN IFR SNOW BAND FROM KFSD-KDVN LATE TONIGHT AND INTO
TUESDAY MORNING. THE TAF SITES WILL ONLY SEE SOME VFR CLOUDINESS.
SOME INSTABILITY DEVELOPS IN THE LOW-LEVELS LATE TUESDAY AFTERNOON
WHICH SHOULD BE SEEN AS BKN-OVC VFR CLOUDS. THERE MAY BE SOME
FLURRIES AROUND AS WELL INTO THE EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
702 PM CDT MON OCT 21 2013
.UPDATE...
ISSUED AT 702 PM CDT MON OCT 21 2013
HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO
IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING
THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE
A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY
OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE
SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST
AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z
NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO
AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF
SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z
GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE
BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH
BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN
TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA
CROSSE FORECAST AREA.
FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT
THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING
WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING
AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS
BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND
WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR
AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA.
CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS
NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER
EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF
THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE
STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY
LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER
NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED
TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS
AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME
CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT
SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT.
THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL
DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO
TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY
THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST
SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z
MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS
SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST
IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW
THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE
COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE
SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH
OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD
FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY
MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION.
TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY
AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C
BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN
THE AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE
WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE
NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING
ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH
THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA.
THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN
THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY
THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO
HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN
THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING
THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM
ENOUGH TO CAUSE THAT CHANGE OVER.
THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB
TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW
LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS
DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE
DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A
TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS
TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS
OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE
50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN.
THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD
TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN
ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY
NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A
WIDESPREAD RAIN EVENT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 700 PM CDT MON OCT 21 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A CLEAR PERIOD THIS
EVENING WILL BE FOLLOWED BY INCREASING MID-LEVEL CLOUDS NORTH OF A
WEATHER SYSTEM MOVING FAST OUT OF THE DAKOTAS TO IL. THIS WILL
CAUSE AN IFR SNOW BAND FROM KFSD-KDVN LATE TONIGHT AND INTO
TUESDAY MORNING. THE TAF SITES WILL ONLY SEE SOME VFR CLOUDINESS.
SOME INSTABILITY DEVELOPS IN THE LOW-LEVELS LATE TUESDAY AFTERNOON
WHICH SHOULD BE SEEN AS BKN-OVC VFR CLOUDS. THERE MAY BE SOME
FLURRIES AROUND AS WELL INTO THE EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
716 AM CDT SUN OCT 20 2013
.UPDATE...
DENSE FOG HAS FORMED OVER A FEW OF THE NORTHERN COUNTIES AND IN
SPOTTY LOCATIONS NEAR JANESVILLE AND ALONG THE WISCONSIN RIVER
VALLEY. HRRR HAS FOG LIFTING AROUND 10 AM. GIVEN SUNRISE IS COMING
AND MARGINAL LENGTH OF ABOUT 3 HOURS...DECIDED TO GO WITH SPECIAL
WEATHER STATEMENT RATHER THAN ZERO LEAD TIME DENSE FOG ADVISORY.
TEMPERATURES ARE RIGHT AROUND FREEZING SO SOME RIMING AND SLIPPERY
SPOTS POSSIBLE.
MEANWHILE FROST AND FROZEN DEW DID FORM AT THE BUZZER WITH THE FOG
HELPING THINGS OUT. WILL LET FROST ADVISORY EXPIRE ON TIME.
&&
.PREV DISCUSSION... /ISSUED 336 AM CDT SUN OCT 20 2013/
TODAY...FORECAST CONFIDENCE IS HIGH.
STRONG UPSTREAM SHORTWAVE TROUGH DIGGING INTO LONG WAVE TROUGH
POSITION TODAY. THIS ALLOWS FLOW TO TURN FROM NORTHWEST TO
WESTERLY DURING THE DAY ALOFT.
SURFACE LOW OF CLIPPER LIKE SYSTEM CURRENTLY EAST OF BIS ND
EXPECTED TO MOVE FROM SOUTHEAST SOUTH DAKOTA TO SOUTHERN MINNESOTA
THIS MORNING...THEN MOVE INTO CENTRAL WISCONSIN THIS AFTERNOON.
DECENT BAROCLINIC ZONE WITH THIS FEATURE WITH STRONG WARM
ADVECTION SPREADING ACROSS WISCONSIN DURING THE DAY. THE STRONGEST
WARM ADVECTION AND DEEPEST MOISTURE IS SHOWN TO CLIP THE FAR NORTH
DURING THE DAY...SO MUCH OF THE DAY MAY BE DRY IN THE SOUTH.
THE LACK OF RAIN IN THE SOUTH AND STRONG WARM ADVECTION REGIME
COULD RESULT IN TEMPERATURES WELL INTO THE 50S AND PERHAPS EVEN
LOWER 60S ALONG THE ILLINOIS BORDER.
STRONG MOISTURE TRANSPORT DEVELOPS JUST AHEAD OF SURFACE COLD
FRONT IN THE LATE AFTERNOON...WITH MODELS SHOWING RAPID INCREASE
IN MOISTURE IN THE SOUTHEAST. PRECIPITABLE WATERS RISE TO ABOUT
0.75" AND THE MODELS SHOW ADDITIONAL BANDS OF PRECIPITATION
FORMING AT THE BUZZER BEFORE THE FRONT MOVES THROUGH IN THE
EVENING. TIMING OF THIS WILL BE CRITICAL AS IT WILL RUN ITS COURSE
BETWEEN ABOUT 21-03Z...MAKING POP FORECASTS SOMEWHAT TRICKY.
TONIGHT...FORECAST CONFIDENCE IS HIGH.
DEEP CLOSED LOW DIGS INTO NORTHERN MINNESOTA WITH -34C 500 MB COLD
CORE. THIS RESULTS IN 70 METER HEIGHT FALLS CENTERED NEAR LAKE
SUPERIOR. SURFACE LOW TURNS TO THE NORTHEAST AND DEEPENS AS IT
MOVES ACROSS THE UP INTO EASTERN LAKE SUPERIOR. THIS USHERS IN
SIGNIFICANT COLD ADVECTION...SUBSIDENCE...AND DEEP DRYING.
LINGERING RAIN IN THE EVENING SHOULD QUICKLY MOVE EAST.
MONDAY THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SHORT TERM MODELS IN DECENT AGREEMENT WITH FEATURES DURING THIS
PERIOD...THOUGH THEY DO SHOW SOME DIFFERENCES. DEEP LOW PRESSURE
SHIFTS FROM EASTERN LAKE SUPERIOR INTO ONTARIO CANADA
MONDAY...THEN BRINGS A SURFACE TROUGH SOUTHEAST THROUGH NORTHEAST
WISCONSIN MONDAY NIGHT.
DEEP 500MB LOW SHIFTS FROM NORTHERN/NORTHEAST MINNESOTA TO EASTERN
LAKE SUPERIOR MONDAY...THEN TO THE EAST MONDAY NIGHT.
GFS/ECMWF/CANADIAN BRING STRONG VORTICITY MAXIMUM EASTWARD BUT
JUST NORTH OF THE AREA MONDAY...WITH SHEARED VORTICITY IN THE AREA
MONDAY NIGHT. THE NAM BRINGS THESE FEATURES SOUTHEAST THROUGH THE
AREA LATER MONDAY AND MONDAY NIGHT. SIDED MORE WITH
GFS/ECMWF/CANADIAN MODELS DURING THIS TIME.
AREA FORECAST SOUNDINGS SHOWING DIURNAL CUMULUS CLOUDS
MONDAY...THEN CLEARING OUT SOMEWHAT MONDAY NIGHT. THERE MAY BE
SOME MIDDLE TO HIGH CLOUDS MONDAY NIGHT...THOUGH CONFIDENCE IS LOW
AT THIS TIME. TIGHT PRESSURE GRADIENT MONDAY WILL ALLOW FOR GUSTY
WEST WINDS...WITH GRADIENT REMAINING FAIRLY TIGHT MONDAY NIGHT.
COOL HIGHS IN THE 40S ARE EXPECTED MONDAY PER 925MB TEMPERATURE
FIELDS AND COLD AIR ADVECTION REGIME. THEY SHOULD DROP LOW ENOUGH
MONDAY NIGHT FOR UPPER 20S TO LOWER 30S ACROSS THE ENTIRE
AREA...ALLOWING FOR A KILLING FREEZE ACROSS THE AREA. DAY SHIFT
SHOULD CONSIDER A FREEZE WATCH FOR MONDAY NIGHT...AND WILL
CONTINUE TO HIGHLIGHT IN HAZARDOUS WEATHER OUTLOOK.
GFS HAS TRENDED A BIT SOUTHWARD WITH THE PASSING LOW PRESSURE
SYSTEM TUESDAY INTO TUESDAY EVENING. 00Z ECMWF ALSO IS SHOWING A
SIMILAR LOW TRACK...WITH QPF JUST CLIPPING THE SOUTHWEST COUNTIES
TUESDAY. THEY BOTH BRING A SHORTWAVE TROUGH THROUGH THE AREA AT
00Z WEDNESDAY. THE NAM/CANADIAN MODELS KEEP THE LOW AND ASSOCIATED
QPF TO THE SOUTHWEST OF THE AREA. ADDED LOW POPS IN THE FAR
SOUTHWEST COUNTIES TUESDAY GIVEN THE GFS/ECMWF LOW TRACKS.
KEPT THE DRY FORECAST GOING ELSEWHERE TUESDAY INTO TUESDAY NIGHT.
KEPT ANY POPS WITH POSSIBLE LAKE EFFECT PRECIPITATION OVER THE
NEARSHORE WATERS ONLY TUESDAY NIGHT...AS LOW LEVEL WINDS LOOK TO
REMAIN PARALLEL TO SHORE AT BEST.
COOL HIGHS IN THE 40S LINGER WITH DIURNAL CUMULUS TUESDAY...WITH
ANOTHER COLD NIGHT/KILLING FREEZE TUESDAY NIGHT IN THE UPPER
20S TO LOWER 30S.
WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE IS MEDIUM.
ECMWF/GFS SHOWING SIMILAR GENERAL TRENDS DURING THIS PERIOD...WITH
SOME DIFFERENCES IN SPECIFIC FEATURES. THEY SHOW A GENERAL
NORTHWEST FLOW AT 500MB CONTINUING ACROSS THE REGION WEDNESDAY
INTO FRIDAY...WITH SEVERAL SHEARED VORTICITY MAXIMA PASSING
THROUGH.
HIGH PRESSURE SYSTEMS SHIFT SOUTHEAST ACROSS THE NORTHERN AND
CENTRAL PLAINS DURING THIS TIME...MAINTAINING THE COLD AIRMASS
OVER THE REGION. GFS FORECAST SOUNDINGS SHOWING SOME DIURNAL
CUMULUS DEVELOPMENT EACH DAY...WITH LIMITED MOISTURE.
THUS...PERIOD SHOULD BE FAIRLY DRY.
GFS THEN BRINGS LOW PRESSURE SOUTHEAST ACROSS THE REGION FRIDAY
NIGHT AND SATURDAY...WITH A STRONG SHORTWAVE TROUGH PASSAGE. THE
ECMWF KEEPS THE AREA DRY FRIDAY NIGHT...WITH THE SHORTWAVE TROUGH
PASSING THROUGH THE REGION SATURDAY. THE SURFACE LOW TAKES A
SIMILAR PATH TO THE GFS...BUT IS ABOUT 12 TO 18 HOURS SLOWER. BOTH
SYSTEMS BRING QPF TO THE AREA. GIVEN SOME UNCERTAINTY HERE...USED
CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD.
AVIATION/12Z TAFS/...
PATCHY FOG MAY IMPACT THE TAF SITES BRIEFLY THIS MORNING WITH
LIGHT WINDS UNDER WEAK SURFACE HIGH.
MUCH OF THE RAIN WILL STAY NORTH OF THE TAF SITES THIS AFTERNOON
AND WILL BE DEVELOPING OVER SOUTHERN WISCONSIN AHEAD OF THE COLD
FRONT LATE IN THE AFTERNOON AND EARLY IN THE EVENING. THERE IS
SUFFICIENT LOW LEVEL DRY AIR TO KEEP CEILINGS IN VFR RANGE IF IT
DOES RAIN.
WINDS WILL INCREASE FROM THE SOUTH TODAY AND THEN TURN WESTERLY
TONIGHT AND BECOME GUSTY IN THE WAKE OF THE COLD FRONT.
MARINE...
STRONG PRESSURE FALLS IN THE LATE AFTERNOON AND EVENING AHEAD OF
THE SURFACE LOW WILL USHER IN GUSTY SOUTH TO SOUTHWEST WINDS THAT
WILL RAPIDLY INCREASE LATE IN THE AFTERNOON. THE WINDS WILL TURN
TO THE SOUTHWEST AND THEN WEST TONIGHT AND THEN NORTHWEST MONDAY
AND TUESDAY. THE COLD FRONT WILL CROSS LAKE MICHIGAN LATER
TONIGHT.
IT WILL BE UNSTABLE AS THE COLD AIR POURS IN TONIGHT SO EXPECT
GUSTY WINDS AND HIGH WAVES IN THE COASTAL WATERS REQUIRING THE
ISSUANCE OF SMALL CRAFT ADVISORY FROM TONIGHT INTO TUESDAY
MORNING. GALE FORCE WINDS ARE EXPECTED AND MUCH HIGHER WAVES
TOWARD OPEN WATERS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ046-047-051-
052-056>060-062>072.
LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT TUESDAY
FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...CRAVEN
MONDAY THROUGH SATURDAY...WOOD
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
138 AM EDT TUE OCT 22 2013
.PREV DISCUSSION... /ISSUED 1039 PM EDT MON OCT 21 2013/
UPDATE...
ADJUSTED SLIGHT POPS ONCE AGAIN FARTHER NORTH THROUGH TONIGHT ACROSS
MUCH OF CENTRAL GEORGIA BASED ON COMBINATION OF PROGGED WEAK VORT
MAX LOCATION AND GENERAL CONSENSUS OF MODEL PRECIP...THOUGH A FEW
OUTLIERS INDICATING POTENTIAL ACROSS NORTH GEORGIA AS WELL. NOT
BUYING INTO THIS RIGHT NOW...THOUGH RECENT HISTORY IN A SIMILAR
SYSTEM PROVED OTHERWISE. WILL CONTINUE TO UPDATE AS
NECESSARY...THOUGH ANY RAIN TOTALS ARE EXPECTED TO BE LIGHT.
LATEST NAM CONDENSATION PRESSURE DEFICITS ARE A BIT LOWER AND MORE
EXPANSIVE THAN EARLIER SO HAVE EXPANDED SOUTHEASTERN FOG
POTENTIAL. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS
DISCUSSION FOLLOWS...
BAKER
PREV DISCUSSION... /ISSUED 813 PM EDT MON OCT 21 2013/
PREV DISCUSSION... /ISSUED 232 PM EDT MON OCT 21 2013/
QUICK SHOT OF RAIN TUESDAY BEFORE COLDER AIR ARRIVES...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST STATES SHOWS HIGH
PRESSURE RIDGE REMAINS IN CONTROL BUT INFLUENCE IS WEAKENING. THIS
IS DUE TO THE APPROACH OF AN UPPER LEVEL TROUGH WHICH RUC ANALYSIS
HAS SITUATED FROM EASTERN ILLINOIS THROUGH MISSOURI AND KANSAS AS
WELL AS ADDITIONAL RIPPLES OF UPPER LEVEL ENERGY CLOSER TO HOME
EMBEDDED IN BROADER TROUGH REGIME. AS FAR AS THE SENSIBLE WEATHER
THIS HAS PRODUCED AT THE SURFACE...PRETTY MUCH A MIXED BAG WITH
LOW CLOUDS IN VICINITY OF RIDGE AXIS AROUND ATHENS JUST STARTING
TO BREAK UP AND A MOSTLY SUNNY DAY ELSEWHERE WHICH IS QUICKLY
GIVING WAY TO INCREASED CIRRUS IN SW FLOW ALOFT. SOME LIGHT
RETURNS FORM THIS ON RADAR FOR SOUTHERN SECTIONS BUT NO EVIDENCE
ANY OF THIS IS REACHING THE GROUND JUST YET.
FOR TONIGHT...GULF COAST WAVE AT THE UPPER LEVELS WILL MOVE INTO
SOUTH GEORGIA THIS EVENING ALLOWING FOR INCREASED LIFT AND
MOISTURE BOTH AT THE MID LEVELS AND EVENTUALLY LOW LEVELS BY
DAYBREAK. IN FACT...MODELS INDICATE LOW CLOUDS REDEVELOPING ACROSS
THE SE ZONES WITH SOME POTENTIAL FOR REDUCED VSBY AS WELL PRIOR TO
DAYBREAK. EXPECT THICKENING CLOUD DECK AND AFOREMENTIONED LIFT TO
RESULT IN -RA WITH LOW END CHANCE ADVERTISED FOR NOW. THIS MAY
PROVE TO BE TOO LOW GIVEN THE AMOUNT OF OMEGA INDICATED BY THE
MODELS BUT HAVE AT LEAST RAMPED UP SOME 10 TO 20 PERCENT ABOVE
GUIDANCE.
SAME HOLDS TRUE FOR TUESDAY AS GUIDANCE POPS LOOK MUCH TOO LOW FOR
THE AMOUNT OF MOISTURE AND LIFT INDICATED BY THE
MODELS...ESPECIALLY THE NAM12. SETUP LOOKS AN AWFUL LOT LIKE THIS
PAST SATURDAY WHEN GUIDANCE HAD NO CLUE AND RAIN WAS MUCH MORE
WIDESPREAD THAN EXPECTED. WITH SECONDARY SHOT OF ENERGY COMING
ACROSS LATE IN THE DAY...FEEL LOW END CHANCE POPS AT LEAST ARE
WARRANTED AND THESE MAY NEED TO BE INCREASED FURTHER IF TRENDS
CONTINUE. ALSO WENT ON THE LOW SIDE OF GUIDANCE FOR TUE MAX TEMPS
BASED ON MORE PRECIP AND CLOUD COVER.
DEESE
LONG TERM /WEDNESDAY THROUGH MONDAY/...
VERY LITTLE CHANGES NEEDED TO THE EXTENDED FORECAST. BY WED MORNING
THE MAIN FRONTAL BOUNDARY WILL HAVE MOVED OFF THE GA/SC COAST WITH
HIGH PRESSURE BUILDING INTO THE REGION FROM THE CENTRAL PLAINS. A
COOLER AIRMASS WILL MOVE IN WITH THIS RIDGE AS WE WILL SE SOME OF
THE COOLEST TEMPS SO FAR THIS SEASON. LOW TEMPS THU MORNING EXPECTED
IN THE 30S AND 40S WITH HIGH TEMPS ONLY GETTING UP INTO THE 60S THU.
THIS COOL AIR REMAINS OVER THE REGION THROUGH THE END OF THE WEEK
AND EVEN GETS REINFORCED FRI/SAT AS ANOTHER STRONGER RIDGE MOVES IN
BEHIND A DRY COLD FRONT FROM THE NORTHERN PLAINS. SOME AREAS ACROSS
EXTREME N GA WILL SE BELOW FREEZING TEMPS SAT MORNING. TEMPS WILL
BEGIN TO REBOUND SUN/MON WILL SEE MAINLY BELOW SEASONAL NORMS WED
THROUGH SAT. NO PRECIP EXPECTED THIS WEEK.
01
&&
.AVIATION...
06Z UPDATE...
MAINLY VFR EARLY THIS MORNING...THOUGH EXPECT MVFR FOG TO DEVELOP
AT AHN/MCN. ISOLATED -RA/-SHRA OUT THERE AS WELL BUT NOT ENOUGH TO
INCLUDE IN ANY TAFS AT THIS POINT. CIGS DROP TO LOW VFR THROUGH
THE MORNING HOURS BUT WITH FAIRLY RAPID IMPROVEMENT LATE THIS
AFTERNOON AS THE FRONT PUSHES THROUGH. WINDS SW AND LIGHT TO BEGIN
WITH...VEERING TO W AND REMAINING AROUND 5KT /SLIGHTLY HIGHER AT
ATL/.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON POSSIBILITY OF -SHRA/-RA.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 49 67 40 / 20 5 0 0
ATLANTA 71 49 63 40 / 20 5 0 0
BLAIRSVILLE 67 43 57 33 / 20 5 0 0
CARTERSVILLE 71 45 62 37 / 20 0 0 0
COLUMBUS 75 53 71 44 / 30 5 0 0
GAINESVILLE 70 48 62 38 / 20 5 0 0
MACON 74 48 72 42 / 30 5 0 0
ROME 71 44 62 37 / 20 0 0 0
PEACHTREE CITY 72 46 66 38 / 20 5 0 0
VIDALIA 75 55 75 44 / 40 20 0 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
357 AM CDT TUE OCT 22 2013
.SHORT TERM /TODAY/...
ISSUED AT 341 AM CDT TUE OCT 22 2013
MAIN CONCERN TODAY WILL OBVIOUSLY BE EVOLUTION OF CURRENT SYSTEM
PASSING THROUGH THE MO VALLEY. DAKOTAS SHORT WAVE/PV ANOMALY
CONTINUES TO STRENGTHEN AS IT APPROACHES WRN IA. ASSOCIATED PRECIP
IS CURRENTLY SOMEWHAT PATCHY...LIKELY DUE TO FAIRLY LOW STATIC
STABILITIES...BUT IS EXPECTED TO ORGANIZE SOMEWHAT MORE LATER THIS
MORNING. FORCING IS DEEP...DRIVEN KINEMATICALLY BY DPVA AND
DIVERGENCE IS LEFT EXIT REGION OF SASKATCHEWAN INTO HIGH PLAINS
JET SEGMENT. THERMODYNAMIC FORCING IS CENTERED INTO IA AND
CURRENTLY NOT THAT STRONG HOWEVER BUT MODELS DO STRENGTHEN THE
THETA-E ADVECTION AND FRONTOGENETICAL FORCING INTO THE MORNING.
THIS COUPLED FORCING WILL RESULT IN INCREASED DENDRITIC GROWTH ZONE
/DGZ/ UPWARD MOTION. MODEL DEPICTIONS OF THIS...LOOKING AT
290-300K ISENT LAYER...ARE SOMEWHAT PROBLEMATIC HOWEVER AND
AFOREMENTIONED LOW STATIC STABILITIES HAVE RESULTED IN COMPACT
MODEL BULLSEYES OF LIFT WHICH ARE DIFFICULT TO EASILY TRANSLATE
INTO HIGHER SNOW RATIOS AND RESULTANT SENSIBLE WEATHER. AREAS OF
HIGHER SNOW RATES MAY END UP BEING NEAR CONVECTIVE AND SOMEWHAT
ISOLATED. TO LOWER CONFIDENCE EVEN FURTHER...LOWEST 500M TEMPS
HOVER RIGHT AROUND CRITICAL RAIN/SNOW VALUES WHICH ARE CO-LOCATED
WITH THE DGZ LIFT. THIS MAKES RAIN/SNOW LINE UNCERTAIN AND WHETHER
THE DGZ OMEGA WILL BE REALIZED IN RAIN OR SNOW. TAKING A BLEND OF
THE HIGHER RES RAP AND NAM WOULD SUGGEST THE BEST LOCATION FOR
ACCUMULATING SNOWS WOULD BE SIMILAR TO PREVIOUS TRACK FROM NW IA
SEWD TO NEAR WATERLOO AND MARSHALLTOWN. STILL HAVE ACCUMS OF AN
INCH OR LESS...WITH A POCKET OF HIGHER AMOUNTS NEAR AN IOWA
FALLS/MARSHALLTOWN/WATERLOO TRIANGLE WHERE SNOW MAY BRIEFLY
INTENSIFY AROUND 12Z OR 15Z. CONFIDENCE IN SNOW AMOUNTS IS QUITE
LOW HOWEVER DUE TO CONCERNS ABOVE AND MELTING ISSUES WITH ROAD
SURFACE TEMPS STILL 35F OR HIGHER AND THE GROUND WARM AS WELL.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 341 AM CDT TUE OCT 22 2013
MAIN FORECAST CONCERN IS WITH WEAK SHORTWAVE TO BRING ADDITIONAL
PRECIP CHANCES ON WEDNESDAY AND THEN CONTINUED COLD TEMPERATURES
THROUGH THE END OF THE WORK WEEK AND INTO THE WEEKEND.
TONIGHT THROUGH WEDNESDAY...THE 22.00Z MODELS RUNS IN DECENT
AGREEMENT WITH BRINGING WEAK VORT MAX FURTHER SOUTH AND CAUSED
FOR A SHIFT IN POPS SOUTHWEST LEAVING THE NORTHEAST PORTIONS OF
THE FORECAST AREA DRY TOMORROW. THERE IS A SMALL WINDOW FOR SNOW
POTENTIAL DURING THE MORNING...ROUGHLY BETWEEN 12-15Z WEDNESDAY
WHEN THE COLUMN BECOMES SATURATED AND REMAINS BELOW
FREEZING AND ENOUGH FORCING IN THE SNOW GROWTH ZONE TO GENERATE
SNOW. THIS WILL BE MAINLY OVER WEST CENTRAL TO NORTHWEST IOWA.
HOWEVER...LOW CONFIDENCE WITH MUCH...IF ANY SNOW ACCUMULATION AS
SURFACE TEMPERATURES LOOK TO QUICKLY RISE ABOVE FREEZING AND
FORCING QUICKLY MOVES SOUTH. AS A RESULT...DECREASED SNOW AMOUNTS
TO LESS THAN HALF AN INCH. THETA-E ADVECTION AND ISENTROPIC LIFT
WILL QUICKLY MOVES FROM NORTHWEST IOWA TO SOUTHEAST IOWA DURING
THE DAY WEDNESDAY. NAM/GFS HAVE DECENT FRONTOGENETICAL FORCING
BETWEEN 750-600MB BY 12Z IN NORTHWEST IOWA AND THEN TRANSITION THE
FORCING INTO SOUTH-CENTRAL TO SOUTHEAST PORTIONS OF THE FORECAST
AREA BY 18Z. WITH THE QUICKER MOVEMENT OF THE SYSTEM...DECREASED
POPS OVER THE WEST AND NORTH PAST 21Z.
THURSDAY THROUGH MONDAY....LARGE SURFACE HIGH BUILDS INTO THE
REGION UNDERNEATH NORTHWEST FLOW ALOFT THROUGH SATURDAY BEFORE
THE GFS/ECMWF BRING A DRY COLD FRONT ACROSS THE STATE SOMETIME
SATURDAY. NEXT LONGWAVE TROUGH BEGINS TO DIG INTO THE WESTERN U.S.
BY EARLY NEXT WEEK PLACING AN INVERTED SURFACE TROUGH OVER IOWA BY
MONDAY. THIS WILL BE THE NEXT BEST CHANCE OF PRECIP TO THE
FORECAST AREA.
&&
.AVIATION...22/06Z
ISSUED AT 1158 PM CDT MON OCT 21 2013
STORM SYSTEM STILL ON TRACK TO IMPACT THE AREA TONIGHT INTO
TUESDAY MORNING. KFOD AND KALO STILL HAVE POTENTIAL FOR IFR TO
MVFR CIGS AND VSBYS WITH SNOW. A PERIOD MVFR CIGS AND
PRECIPITATION ARE EXPECTED AT THE OTHER LOCATIONS AS WELL. A
SWITCH TO NORTHWEST WINDS AND RISING CIGS WILL ARRIVE BY THE
AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...PODRAZIK
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS WICHITA KS
334 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
TODAY:
ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE
OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING
ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING.
OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT
RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND
POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS
AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE
FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES
WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY.
TONIGHT:
RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES
EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS
WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR
WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL
LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST
ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF
NEEDED.
WED-THU:
QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD
OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY.
TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN
HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS.
TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT
WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE
TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION
CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF
MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE
TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN
FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW
DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN
TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON
ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE
BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON
MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST
OF THE DAY. -HOWERTON
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1141 PM CDT MON OCT 21 2013
FAIRLY QUIET VFR CONDITIONS ANTICIPATED THE NEXT 24 HOURS...WITH
GUSTY NORTHWEST WINDS TUESDAY THE PRIMARY CONCERN. LIGHT SOUTHWEST
WINDS ANTICIPATED TONIGHT...INCREASING SOME TOWARD DAYBREAK AND
GRADUALLY TURNING MORE WESTERLY. COLD FRONT WILL MOVE SOUTHEAST
ACROSS THE REGION TUESDAY MORNING...WITH STRONG/GUSTY NORTHWEST
WINDS IN ITS WAKE. FURTHERMORE...MID-LEVEL CLOUDS WILL BE ON THE
INCREASE FROM THE NORTHWEST OVERNIGHT...WITH SLIGHT CHANCE FOR A
FEW PASSING SPRINKLES FOR MAINLY RSL-SLN. DIURNAL CUMULUS AROUND
6000 FT AGL SHOULD PREVAIL ACROSS THE AREA BY TUESDAY AFTERNOON AS
COOLER AIR ALOFT SETTLES SOUTH.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 68 39 71 38 / 10 0 0 0
HUTCHINSON 67 38 69 37 / 10 0 0 0
NEWTON 65 38 69 36 / 10 0 0 0
ELDORADO 66 35 69 36 / 10 0 0 0
WINFIELD-KWLD 68 37 73 38 / 10 0 0 0
RUSSELL 66 37 67 34 / 0 0 0 0
GREAT BEND 66 37 68 34 / 0 0 0 0
SALINA 66 36 69 36 / 10 0 0 0
MCPHERSON 66 37 69 36 / 10 0 0 0
COFFEYVILLE 68 36 69 38 / 10 0 0 0
CHANUTE 67 33 65 35 / 10 0 10 0
IOLA 65 32 65 35 / 10 0 10 0
PARSONS-KPPF 67 33 67 34 / 10 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053-
069>072-094>096-099-100.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE OCT 22 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND
A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL
LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE
SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH
EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A
BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL
CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED
BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE
IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE
ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE.
WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE
RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET
BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE
BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE
EAST.
TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS
850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR
MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF
SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE
SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING
JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON.
TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO
THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN
850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND
BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR
LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL
INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR
LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EDT TUE OCT 22 2013
THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE
UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL
REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL
BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE
SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS
WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND
THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT
AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND
8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE
EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO
WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH
WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE
NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF
GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER
THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW
FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST).
WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA
LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE
LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR
THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE
LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO
BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A
QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE
TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED
CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE
EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP
PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO
WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS
AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR).
THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER
SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO
THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT
EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ.
THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN
THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN
ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE
AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO
EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO
1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE
SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL
ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER
BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS.
THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS
IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE
SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL
BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS
SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP.
ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT
PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN
PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT
AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE
EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT
NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA
AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS
TO LESSEN.
THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT
AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER
GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO
EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE
ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND
THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA.
FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH
THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING
SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO
SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE
EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION
OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE
NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT
THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST
WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL
HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN
GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER
TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS
LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A
REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST
TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE
DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST
COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED
FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE
AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES
WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE
TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 123 AM EDT TUE OCT 22 2013
ALTHOUGH THERE MAY BE SOME IFR CONDITIONS AT IWD/CMX EARLY THIS MRNG
WITH UPSLOPE GUSTY NW FLOW IN THE WAKE OF TROF PASSAGE...EXPECT MVFR
WX TO DOMINATE MOST OF THIS FCST PERIOD WITH CHILLY NW FLOW BTWN
DEPARTING LO PRES TROF AND INCOMING HI PRES RDG. CLOSER APRCH OF THE
SFC RDG/WEAKER PRES GRADIENT LATER TODAY WL ALLOW GUSTY NW WINDS TO
DIMINISH. AT SAW...VFR CONDITIONS EARLY WL GIVE WAY TO A PERIOD OF
MVFR CIGS WITH ARRIVAL OF DEEPER MSTR ACCOMPANYING THE TROF...BUT
VFR WX WL RETURN THIS AFTN WITH CLOSER APRCH OF RDG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE OCT 22 2013
NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY
AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH.
HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE
NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE
THROUGH THE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ005.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ264>267.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
347 AM EDT TUE OCT 22 2013
.SHORT TERM... TODAY AND TONIGHT
CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL
MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR
MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED
ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND
POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW
LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM
THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO
SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS
TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE
LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO
THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO
SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT
WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS
RECOVER INTO THE MID AND UPPER 40S.
THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS
BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING
THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE
THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE
SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION
OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A
CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO
SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE
AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING
GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE
SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS
REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH
THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL
DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A
CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF
THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD
ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS
INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY
LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE
EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK
LOOK ON TARGET BY SUNRISE WEDNESDAY.
&&
.LONG TERM...
LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT
LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE
DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE
MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH
PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN
THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C.
IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS
TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN
WILL TEND TO BE SHUNTED TO OUR SOUTHWEST.
THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED
TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE
HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH
ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST
INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED
AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL
FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV
ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED
WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT
POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE
OHIO VALLEY.
MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE
SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER
CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO
PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS
NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR
CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING
WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S.
SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK
INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT
RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH
PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK
UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN
REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS
GRIP ON THE AREA.
&&
.MARINE...
A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY
WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL
LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT
GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN
THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE
SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP
WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE
WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON
TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH
TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND
WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE
WEEK.
&&
.AVIATION...ISSUED 1152 PM EDT MON OCT 21 2013
//DISCUSSION...
LAKE EFFECT STRATUS WILL BE THE PREDOMINANT CHALLENGE THIS FORECAST
AS THE SEASON GETS OFF TO A BIT OF AN EARLY START AS COLD...WESTERLY
FLOW BECOMES ESTABLISHED AROUND BASE OF EXPANSIVE UPPER TROUGH OVER
THE AREA. THE LOW LEVEL FLOW WILL BE SOUTHWEST OVERNIGHT IN ADVANCE
OF NEXT EMBEDDED SHORTWAVE TROUGH...WHICH WILL TEND TO FOCUS CIGS
FROM PTK NORTH WITH SCT STRATUS MUCH OF THE TIME YIP/DTW/DET. WITH
FLOW VEERING TO WEST AND THEN NORTHWEST TUESDAY INTO TUESDAY EVENING
WITH THE PASSAGE OF THIS SURFACE TROUGH...MVFR/LOWER VFR CIGS WILL
EXPAND BACK SOUTH TO COVER ALL TERMINALS.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS AOB 5000 FEET AFTER 15Z TUESDAY WITH
HIGHER CONFIDENCE AFTER 00Z.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM
TUESDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8
AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
SANILAC...UNTIL 8 AM WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...BT
LONG TERM....JVC
MARINE.......BT
AVIATION.....DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
319 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT TUE OCT 22 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE UPPER
LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA BEING SHUNTED
INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES DROP SOUTHEAST
THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE MAIN SHORTWAVE OF
INTEREST FOR THE SHORT TERM CAN BE SEEN OVER EASTERN SOUTH DAKOTA...
AND IS HELPING TO GENERATE THE LIGHT PCPN SEEN ON RADAR AND SURFACE
OBS OVER FAR SOUTHWEST MINNESOTA... EASTERN SOUTH DAKOTA... AND
NORTHERN IOWA. MOST OF THIS ACTIVITY LOOKS LIKE IT WILL REMAIN SOUTH
OF OUR AREA THIS MORNING... SO MAINLY JUST MENTIONED SOME FLURRIES
OR LOW POPS WITH NO SNOWFALL ACCUMULATIONS. OTHERWISE... TODAY LOOKS
BENIGN ACROSS THE FORECAST AREA... WITH SOME PEAKS OF SUN
INTERSPERSED WITH LINGERING STRATOCU. WE MAINTAIN SOMEWHAT OF A
925-850MB THERMAL TROUGH OVER THE AREA TODAY... WHICH SHOULD KEEP
PLENTY OF CLOUDS IN PLACE... AND LATEST 11-3.9 MICRON IMAGERY SHOWS
PLENTY OF CLOUDS TO THE NORTH DROPPING SOUTH WITH TIME. HOWEVER...
THERE ARE INDICATIONS THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE
ANTICYCLONIC THIS AFTERNOON... WHICH COULD WORK TO GENERATE SOME
DECENT BREAKS IN THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY
FOR NOW GIVEN SATELLITE TRENDS AND FORECAST PROFILES... AND WENT
WITH MOSTLY CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT
SHORTWAVE OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS
MORNING/S... AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT
INTO WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN
WILL ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL
MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER
THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND
FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY
SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH WILL
ONCE AGAIN BE QUITE A BIT BELOW NORMAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE OCT 22 2013
EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS
IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST COAST
OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES REGION.
THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP A CYCLONE
ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY COLD AIR WILL
CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST FOR THE NEXT
COUPLE OF DAYS.
MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN
MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY
THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN STREAM
TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE COAST OF NEW
FOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE NORTHERLY WINDS
CURRENTLY IN PLACE ACROSS THE REGION TO BECOME MORE WESTERLY BY THE
END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE WILL LEAD LEE SIDE
WARMING ON THE FOOTHILLS OF THE ROCKIES...AND THIS WARM AIR WILL
MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. IN
FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE
SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850. NOT EXACTLY
A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS. THIS WARM UP WILL
BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS LOW LEVEL WARM AIR
ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS SOUTHERN CANADA...AND
DRIVE A WEAK COLD FRONT THROUGH THE REGION. THIS FRONTAL BOUNDARY
WILL EVENTUALLY BECOME ORIENTED EAST/WEST...AND SET THE STAGE FOR A
POTENTIALLY SIGNIFICANT STORM SYSTEM TO DEVELOP NEXT WEEK OVER THE
MIDWEST.
IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP
MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO
MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE
SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW CLIMATOLOGY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1057 PM CDT MON OCT 21 2013
SKIES HAVE CLEARED ACROSS A GOOD PART OF WEST CENTRAL AND CENTRAL
MN INTO SOUTHERN MN AND WISCONSIN...BUT NEXT SOUTHWARD SURGE OF
CLOUDS SEEMS TO BE TAKING PLACE PER SATELLITE AND OBS. LAMP DATA
SUGGEST SOME POTENTIAL FOR MVFR CEILINGS INTO OUR NORTHERN AND
EASTERN TAF SITES AFTER 09Z-10Z... AND ESPECIALLY AT KRNH AND
KEAU. OBS FROM PARK RAPIDS...BRAINERD INTO NWRN WISC DO SHOW A
BROAD AREA OF CEILINGS AROUND O15-025. HAVE ALSO ADDED SOME MVFR
AT KAXN BASEED ON OBS EVEN THOUGH MODEL DATA ARE NOT AS BULLISH ON
IT. NOT SURE WHAT TO MAKE OF EXPANSIVE MOISTURE TUESDAY
EVENING...PATTERN DOES NOT SEEM CONDUCIVE AS SHOULD BE SOME MODEST
SUBSIDENCE LATER TUESDAY AFTERNOON INTO THE EVENING.
AND IN SW MN...CLIPPER MENTIONED IN SHORT-TERM WILL LIKELY PASS
FAR ENOUGH WEST AND SOUTH OF KRWF TO ONLY BRING SOME OVC MID LEVEL
CLOUDS. LIGHT SNOW SHOULD BE FARTHER SOUTH AND WEST. FEW FLURRIES
AT BEST AT KRWF.
KMSP...MOSTLY CLEAR SHORTLY AFTER MIDNIGHT BUT THEN CEILINGS AROUND
045 SHOULD DROP SOUTHWARD AND MAY WELL CLIP KMSP. THIS WILL MOST
LIKELY ARRIVE AFTER 11Z. THERE ARE A COUPLE HINTS IN SOME MODEL
DATA THAT CEILINGS MAY EVEN DROP TO 2500 OR SO AROUND 11Z...BUT
NOT AT ALL CONFIDENT IN THIS...AND HAVE NOT ADDED ANY MVFR CEILINGS.
BUT IT IS SOMETHING TO WATCH FOR.
/OUTLOOK FOR KMSP/
WED...VFR. SW WIND LESS THAN 5 KT BECMG NW 5-10 KT.
THU...VFR. NW WIND 10-15 KT.
FRI...VFR. SW WIND 10 KT INCRG TO 15 TO 20 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...99
LONG TERM...JRB
AVIATION...TDK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT TUE OCT 22 2013
MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS
MORNING AND TEMPERATURES.
CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS
HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA
EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE
CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS
HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE.
MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH
THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE
THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID
DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS
THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE
AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF
THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM
MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE
MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND
PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL
BE THE EXTENT OF THE PRECIPITATION.
THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING
AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND
INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS
DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH
AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT
IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP
TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER
TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE
SOUTHWEST.
SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT
TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL
BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN
THE CLOUDS MOVE THROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 425 AM CDT TUE OCT 22 2013
BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES.
THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE
BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A
BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE
WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA
COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE
LONG TERM.
THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH
FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR
NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS
TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS
MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE
EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT
OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE
JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND
THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE
INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH
TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED
TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD
BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST
HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD
BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE
TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY
SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS
WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW
TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO
NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID
TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY
RISING BY THE OVERNIGHT HOURS.
TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE
REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE
ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL
SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN
ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT
SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A
NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED
SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST
TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY
STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR
ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD
FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG
IT TO OUR EAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1225 AM CDT TUE OCT 22 2013
LOW TO MID LEVEL CLOUDS WILL MOVE THROUGH THE KGRI TERMINAL AREA
THROUGH THE PERIOD. CEILINGS SHOULD REMAIN VFR. THE MAIN QUESTION
IS WHETHER THE LIGHT SHOWERS OR SPRINKLES WILL FALL AT THE KGRI
TERMINAL. THERE ARE A FEW OUT THERE EARLY THIS MORNING AND THERE
COULD BE A FEW DROPS THAT FALL...BUT THAT WOULD BE THE MOST. WINDS
WILL BE GUSTY DURING THE MORNING BUT START TO DIMINISH DURING THE
LATE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
305 AM EDT TUE OCT 22 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC
TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE
AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL
SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY
AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN
MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW
YORK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING
EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT
RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO
REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z,
CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE
WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR
NE PA.
715 PM UPDATE...
NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS
SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO.
PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES
NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT
06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT
UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY
TEMPS RIGHT ON TARGET AT THIS TIME.
PREV DISCUSSION BLO...
BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN
CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT
APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION
VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS
IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS
THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH
PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY
ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS
HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING
ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND
FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS
TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH
OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH
SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY
AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS
IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE
CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE
AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN
FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY
OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE
WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS
DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY.
FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY
ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY
UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE
BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE
40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR
FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING
FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN
COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE
OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE
BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS
OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY.
MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT
ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY
WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD
CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES
LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW
ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS
THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS
RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY
MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM
TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
3 AM UPDATE...
GRIDS ADJUSTED TO ACCOUNT FOR WPC AND MODEL TRENDS. LITTLE CHANGE.
UPPER TROUGH PATTERN LATE WEEK INTO WEEKEND...LOOKS TO SHIFT
TEMPORARILY INTO A FLATTER W OR WSW FLOW ALOFT BY EARLY NEXT WEEK.
THIS WILL ALLOW TEMPERATURES TO EDGE UP CLOSER TO CLIMATOLOGY...AND
A BREAK IN PRECIPITATION CHANCES SUNDAY NIGHT THROUGH AT LEAST
MONDAY NIGHT. UNTIL THEN...UNSETTLED CHILLY CYCLONIC FLOW WITH
GREAT LAKES HELPING TO YIELD SCATTERED -SHRA/-SHSN MAINLY IN
CENTRAL NY.
PREVIOUS DISCUSSION...
LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE
TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE
SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS
IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING
OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO
PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT
THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO
DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH
SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...
MAIN WEATHER FEATURE OF INTEREST IS A COLD FRONT SET TO MOVE WEST
TO EAST ACROSS THE TERMINALS 10Z-15Z...AND A VFR CIG HAS ALREADY
FORMED AHEAD OF IT. FRONT WILL COME THROUGH WITH LIMITED
MOISTURE...THUS ONLY KNOCKING TERMINALS /EXCEPT KAVP/ DOWN
TEMPORARILY INTO MVFR WITH FRONTAL PASSAGE AND LIGHT SHOWERS. SEE
TAFS FOR SPECIFIC TIMING. BRIEF FUEL ALTERNATE MVFR ALSO POSSIBLE
HILLTOP TERMINALS KBGM-KITH. WINDS TO VEER FROM S-SSW TO W-WNW AS
FRONT PASSES. 4-5 KFT AGL CIG LATE MORNING-EARLY AFTERNOON...THEN
DRYNESS OF AIR MASS WILL SCATTER THINGS OUT BY LATE AFTERNOON INTO
EVENING.
OUTLOOK...
LATE TUE NGT...VFR.
WED/THU/FRI/SAT...TIMES OF MVFR CIGS AND SCT -SHRA MAINLY CENTRAL
NY TERMINALS WITH MOISTURE OFF OF GREAT LAKES. -SHSN MAY MIX IN AT
TIMES LATE NIGHT-EARLY MORNING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN/RRM
SHORT TERM...JAB
LONG TERM...MDP
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
149 AM EDT TUE OCT 22 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC
TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE
AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL
SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY
AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN
MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING
EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT
RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO
REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z,
CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE
WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR
NE PA.
715 PM UPDATE...
NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS
SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO.
PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES
NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT
06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT
UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY
TEMPS RIGHT ON TARGET AT THIS TIME.
PREV DISCUSSION BLO...
BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN
CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT
APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION
VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS
IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS
THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH
PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY
ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS
HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING
ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND
FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS
TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH
OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH
SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY
AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS
IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE
CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE
AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN
FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY
OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE
WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS
DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY.
FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY
ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY
UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE
BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE
40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR
FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING
FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN
COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE
OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE
BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS
OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY.
MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT
ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY
WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD
CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES
LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW
ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS
THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS
RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY
MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM
TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE
TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE
SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS
IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING
OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO
PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT
THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO
DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH
SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...
MAIN WEATHER FEATURE OF INTEREST IS A COLD FRONT SET TO MOVE WEST
TO EAST ACROSS THE TERMINALS 10Z-15Z...AND A VFR CIG HAS ALREADY
FORMED AHEAD OF IT. FRONT WILL COME THROUGH WITH LIMITED
MOISTURE...THUS ONLY KNOCKING TERMINALS /EXCEPT KAVP/ DOWN
TEMPORARILY INTO MVFR WITH FRONTAL PASSAGE AND LIGHT SHOWERS. SEE
TAFS FOR SPECIFIC TIMING. BRIEF FUEL ALTERNATE MVFR ALSO POSSIBLE
HILLTOP TERMINALS KBGM-KITH. WINDS TO VEER FROM S-SSW TO W-WNW AS
FRONT PASSES. 4-5 KFT AGL CIG LATE MORNING-EARLY AFTERNOON...THEN
DRYNESS OF AIR MASS WILL SCATTER THINGS OUT BY LATE AFTERNOON INTO
EVENING.
OUTLOOK...
LATE TUE NGT...VFR.
WED/THU/FRI/SAT...TIMES OF MVFR CIGS AND SCT -SHRA MAINLY CENTRAL
NY TERMINALS WITH MOISTURE OFF OF GREAT LAKES. -SHSN MAY MIX IN AT
TIMES LATE NIGHT-EARLY MORNING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN/RRM
SHORT TERM...JAB
LONG TERM...
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1232 AM EDT TUE OCT 22 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC
TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE
AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL
SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY
AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN
MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING
EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT
RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO
REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z,
CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE
WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR
NE PA.
715 PM UPDATE...
NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS
SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO.
PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES
NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT
06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT
UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY
TEMPS RIGHT ON TARGET AT THIS TIME.
PREV DISCUSSION BLO...
BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN
CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT
APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION
VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS
IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS
THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH
PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY
ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS
HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING
ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND
FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS
TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH
OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH
SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY
AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS
IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE
CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE
AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN
FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY
OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE
WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS
DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY.
FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY
ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY
UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE
BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE
40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR
FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING
FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN
COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE
OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE
BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS
OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY.
MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT
ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY
WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD
CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES
LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW
ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS
THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS
RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY
MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM
TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE
TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE
SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS
IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING
OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO
PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT
THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO
DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH
SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
00Z UPDATE...
VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY EVENING AHEAD OF AN
APPROACHING COLD FRONT FROM THE WEST. WINDS WILL WEAKEN QUICKLY
AFTER SUNSET AS WE LOSE MIXING FROM THE SUN AND REMAIN UNDER 12
KNOTS. THE COLD FRONT WILL MOVE FROM W TO E EARLY TUESDAY MORNING
FORCING THE WINDS TO TRANSITION FROM A SOUTHERLY FLOW TO A
WEST/NORTHWESTERLY FLOW. LIGHT RAIN SHOWERS WILL ACCOMPANY THIS
FRONT AND CAUSE RESTRICTIONS OF MVFR CIGS AND VISBYS AT KRME...
KSYR... AND KITH THROUGH 15Z TUESDAY MORNING. THE REMAINING TAFS
SITES ARE EXPECTED TO REMAIN VFR AS THE FRONT PASSES WITH LIGHT RAIN
SHOWERS. WINDS TUESDAY AFTERNOON WILL PICK UP CAUSING LINGERING MVFR
CIGS TO LIFT TO VFR.
OUTLOOK...
TUE NGT...VFR.
WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL
NY AFFECTING RME/SYR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN/RRM
SHORT TERM...JAB
LONG TERM...
AVIATION...KAH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
422 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE
ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION
GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR
AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN
SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD
EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A
HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES
EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE
MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES
BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON
HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS
UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S.
ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER
TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM
WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING
HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES
WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT
BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER
THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE
TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF
AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD
THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE
CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF
HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q
VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY
OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF
AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN
ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA
OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY
LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW
WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING
TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST
OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST
CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR
TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA
OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE
AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME
TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP
WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND
11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL
REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF
HIGHS ONLY IN THE 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS
TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO
WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY.
ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST
THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS
SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION
AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY
LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL...
WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE
PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND
THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH
HIGHS THURSDAY AGAIN IN THE 40S.
LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE
NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY
NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS
SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT
OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL
CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A
COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING
BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF
OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A
FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA
TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD
HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS
AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK.
MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN
ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER
PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1006 PM CDT MON OCT 21 2013
DEVELOPMENT OF MVFR CEILINGS ON TRACK AS PRECIPITATION BAND WORKS
INTO THE AREA LATE EVENING. WILL CONTINUE TO SEE SOUTHEAST SPREAD
IN MVFR CEILINGS...AND WITH RAIN MIXING WITH OR CHANGING TO SNOW FOR
KHON/KFSD AREAS EASTWARD...WILL SEE PERIODS OF IFR VISIBILITIES
AND CEILINGS AS WELL. EVENTUALLY...CEILINGS WILL BEGIN TO LIFT AS
FLOW TURNS NORTHERLY AND DRIVES LOWER LEVEL DRY AIR SOUTHWARD
DURING THE MORNING HOURS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JH
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT TUE OCT 22 2013
AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA
NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED
IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD
OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO
MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K
ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST
AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS
RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES
IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A
VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DEDRITIC
GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF
DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS
SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT
CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT
COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE
BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH
OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF
A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN.
FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5
C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS
WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 AM CDT TUE OCT 22 2013
ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE
TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A
RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC
LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH
LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN
30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF
NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND
THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER
EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT
THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN.
AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF
COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES
TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK
TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE
OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO
KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR
FRIDAY NIGHT INTO SATURDAY.
LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT
THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE
TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS...
THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS
WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS
COULD BE OUR FIRST TASTE OF INDIAN SUMMER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CDT MON OCT 21 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS A WEATHER SYSTEM
TRAVELS SOUTH OF THE TAFS. PROLONGED NORTHWEST FLOW AND THE
WEATHER SYSTEM IN IOWA WILL WILL BRING CLOUDS OF THE VFR VARIETY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1152 PM CDT MON OCT 21 2013
.UPDATE...
ISSUED AT 938 PM CDT MON OCT 21 2013
HAVE BEEN FOLLOWING THE TRENDS OF THE HRRR AND RAP ALL EVENING
AND THE 22.00Z NAM HAS NOW COME IN AS WELL...ALL WITH THE SNOW
STRIPE FURTHER SOUTH IN IA BY 1-2 COUNTIES. HAVE TRENDED THE
FORECAST THAT WAY WITH REDUCED PRECIPITATION CHANCES...AND LESS
SNOWFALL /NOW ABOUT 0.5 INCHES VERSUS 1 INCH/ IN FAR SOUTH. WITH
CLEAR SKIES AND SOME LOW-LEVEL RIDGING AND LIGHT WIND...HAVE ALSO COOLED
LOW TEMPERATURES ACROSS THE SOUTH TOO.
FORECAST SHOULD BE UP TO THE WEB SITE AND IN PRODUCTS SHORTLY.
UPDATE ISSUED AT 702 PM CDT MON OCT 21 2013
HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO
IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING
THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE
A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY
OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE
SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST
AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z
NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO
AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF
SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z
GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE
BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH
BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN
TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA
CROSSE FORECAST AREA.
FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT
THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING
WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING
AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS
BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND
WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR
AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA.
CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS
NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER
EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF
THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE
STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY
LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER
NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED
TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS
AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME
CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT
SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT.
THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL
DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO
TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY
THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST
SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z
MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS
SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST
IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW
THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE
COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE
SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH
OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD
FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY
MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION.
TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY
AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C
BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN
THE AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 307 PM CDT MON OCT 21 2013
ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE
WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE
NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING
ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH
THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA.
THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN
THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY
THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO
HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN
THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING
THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM
ENOUGH TO CAUSE THAT CHANGE OVER.
THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB
TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW
LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS
DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE
DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A
TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS
TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS
OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE
50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN.
THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD
TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN
ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY
NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A
WIDESPREAD RAIN EVENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM CDT MON OCT 21 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS A WEATHER SYSTEM
TRAVELS SOUTH OF THE TAFS. PROLONGED NORTHWEST FLOW AND THE
WEATHER SYSTEM IN IOWA WILL WILL BRING CLOUDS OF THE VFR VARIETY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1031 AM EDT TUE OCT 22 2013
...FOGGY MORNING TRANSITIONS TO A SOGGY EVENING AS A COLD FRONT
APPROACHES...
.UPDATE...
MOIST AIRMASS AHEAD OF AN APPROACHING COLD FRONT PRODUCED PATCHES
OF DENSE FOG FOR PORTIONS OF THE EASTERN TAMPA BAY AREA THIS
MORNING...WITH AREAS OF FOG OVER MUCH OF WEST CENTRAL AND
SOUTHWEST FLORIDA THIS MORNING. AS THE DAYTIME HEATING
CONTINUES...EXPECT THE FOG TO IMPROVE AND THE LOW STRATUS CLOUDS
TO LIFT. ALLOWED DENSE FOG ADVISORY TO EXPIRE AT 10 AM...AND ISSUED
UPDATED ZONES TO REMOVE MENTIONS OF FOG.
OTHERWISE...06Z MAV GUIDANCE IS TRENDING TOWARDS THE RAINS AHEAD
OF THE FRONT ARRIVING FASTER AND AFFECTING THE TAMPA BAY AREA
SOUTHWARD SOONER. HAVE UPDATED THE FORECAST TO SHOW THESE ELEVATED
RAIN CHANCES. LINE OF RAIN CAN BE SEEN ON RADAR IN THE GULF ABOUT
TO ENTER THE TBW OUTER WATERS AND 07Z HRRR GUIDANCE SHOWS THE
POTENTIAL FOR A LINE OF SHOWERS FROM TAMPA BAY NORTHWARD LATE
AFTERNOON INTO THE EARLY EVENING. RAISED POPS AFTER 00Z AS
WELL...TO ACCOUNT FOR THE INCREASING CHANCE OF SOME RAIN OVERNIGHT
AS THE MAIN LINE MOVES THROUGH. WILL CONTINUE TO KEEP AN EYE ON
THESE TRENDS FOR THE NEXT FORECAST PACKAGE ISSUANCE LATER THIS
AFTERNOON.
&&
.AVIATION...
IFR/LIFR CIGS AND VSBYS AT KLAL AND MVFR VSBYS AT KTPA WILL ERODE
AWAY BY 15Z THIS MORNING WITH VFR EXPECTED AT ALL TERMINAL SITES
THE REMAINDER OF TODAY WITH AN INCREASE IN MID AND HIGH LEVEL CLOUDS
DURING THE AFTERNOON WITH SOME VCSH FROM KSRQ NORTH TO KTPA...KPIE
AND KLAL AFTER 22Z. CIGS AND VSBY WILL BEGIN TO LOWER TONIGHT WITH
CLOUDS THICKEN AND RAIN CHANCES INCREASE ACROSS THE REGION AHEAD OF
COLD FRONT...WITH MVFR CIGS DEVELOPING AT ALL SITES AFTER 23/09Z.
LIGHT AND VARIABLE WINDS WILL BECOME SOUTHWEST TO WEST AROUND 10 KNOTS
AFTER 15Z.
&&
.MARINE...
LINE OF RAIN MOVING INTO THE WATERS IN THE NEXT FEW HOURS. EXPECT
CONDITIONS TO DETERIORATE THROUGHOUT THE DAY. NO MAJOR CHANGES TO
THE FORECAST...EXPECTING STRONGER WINDS AND WAVES BEHIND THE FRONT
THAT COULD REACH CAUTIONARY...AND POSSIBLY ADVISORY...CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 86 74 84 63 / 50 70 40 10
FMY 89 75 87 68 / 30 60 60 40
GIF 89 72 84 62 / 50 60 40 10
SRQ 86 73 85 64 / 40 70 50 20
BKV 86 71 83 54 / 60 70 30 10
SPG 86 76 84 69 / 50 70 40 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...02/GARCIA
AVIATION...57/MCMICHAEL
AREA FORECAST DISCUSSION
NWS MIAMI FL
958 AM EDT TUE OCT 22 2013
.UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A FRONTAL BOUNDARY EXTENDING
WSW FROM CENTRAL FLORIDA TO THE SOUTHWEST GULF OF MEXICO AND A
WEAK RIDGE AXIS EXTENDING WWD ACROSS THE BAHAMAS. OBSERVATIONS
AROUND THE LOCAL AREA SHOWED LIGHT SSE WINDS AROUND THIS RIDGE
AXIS WITH DEWPOINTS IN THE MID 70S. ALTHOUGH THERE WERE SOME SMALL
PATCHES OF FOG AROUND AND JUST BEFORE DAYBREAK...THE LATEST
SATELLITE IMAGERY INDICATED THOSE AREAS HAVE BURNED OFF WITH
MOSTLY CLEAR SKIES. THE MORNING SOUNDING AT MIA SHOWED SSE LOW-
LEVEL WINDS VEERING TO THE SW ABOVE 850 MB AND A PWAT OF 1.75".
THE LATEST RUC ANALYSIS LINES UP WELL WITH THE CURRENT SYNOPTIC
PATTERN AND GENERALLY INDICATES THE DEEP LAYER MOISTURE INCREASING
THROUGH THE DAY AS AN UPPER TROUGH AND FRONTAL BOUNDARY APPROACH
THE AREA. THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY
SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS INITIATING ACROSS
PORTIONS OF THE AREA...THEN BECOMING CONCENTRATED OVER THE
NORTHEASTERN SECTIONS OF THE AREA OR AROUND THE LAKE REGION TO THE
PALM BEACH COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS.
THE CURRENT FORECAST PACKAGE REMAINS ON TRACK WITH NO MAJOR UPDATES
NECESSARY AT THIS TIME. 85/AG
&&
.PREV DISCUSSION... /ISSUED 751 AM EDT TUE OCT 22 2013/
AVIATION...
TERMINAL KAPF COULD EXPERIENCE BRIEF PERIODS OF MINOR VISIBILITY
RESTRICTIONS AND SCT002 IN THE EARLY MORNING HOURS DUE TO FOG/LOW
STRATUS. BY 12Z- 13Z THE FOG/STRATUS SHOULD DISSIPATE BUT
REMAINING VFR. THUNDERSTORM ACTIVITY THIS AFTERNOON IS EXPECTED TO
BE ISOLATED AND MAINLY IN THE VICINITY OF TERMINAL KPBI BUT VCTS
NOT ASSIGNED WITH COVERAGE EXPECTED TO BE LOW.
BD/KOB
PREV DISCUSSION... /ISSUED 400 AM EDT TUE OCT 22 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS FROM LAST EVENING HAVE DISSIPATED AND
GIVEN WAY TO MOSTLY CLEAR SKIES ACROSS THE AREA. DUE TO THE WET
GROUND AND A DIFFUSE BOUNDARY DRAPED ACROSS THE CENTRAL FLORIDA
PENINSULA...AREAS OF FOG WILL BE POSSIBLE THIS MORNING MAINLY
ACROSS INTERIOR AREAS.
MOISTURE RICH SOUTHWEST FLOW WILL CONTINUE THROUGH THE DAY WITH
CHANCES FOR AFTERNOON SHOWERS AND A FEW THUNDERSTORMS AGAIN MAINLY
ACROSS THE INTERIOR. HUMIDITY LEVELS WILL ALSO INCREASE AS A
RESULT WITH PWAT VALUES APPROACHING 2 INCHES.
THE FORECAST FOCUS WILL THEN TURN TO THE APPROACHING COLD FRONT
THAT IS EXPECTED TO ENTER THE AREA WEDNESDAY AFTERNOON. AS THE
FRONT PUSHES THROUGH...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE BOUNDARY. WITH PWATS NEARING 2.25 INCHES BY
WEDNESDAY EVENING...THE MAIN THREAT AT THIS TIME WITH ANY STORMS
WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WEDNESDAY
AFTERNOON AND EVENING.
AS THE FRONT CLEARS THE AREA LATE WEDNESDAY NIGHT...MODELS STILL
INDICATE DEEP MOISTURE OVERRUNNING THE BOUNDARY WITH CONTINUED
SOUTHWEST FLOW ALOFT THROUGH THURSDAY. THIS WILL KEEP RAINFALL
CHANCES THROUGH THURSDAY WITH BETTER CHANCES TO THE SOUTH. MODELS
THEN STAY IN AGREEMENT WITH A SECONDARY FRONT SURGING THROUGH THE
AREA FRIDAY BRINGING A MUCH DRIER AIR MASS INTO SOUTH FLORIDA
ALONG WITH BELOW NORMAL TEMPERATURES. FAIRLY WIDESPREAD 50S SHOULD
BE SEEN ACROSS INTERIOR AREAS BOTH SATURDAY AND SUNDAY MORNINGS
WITH HIGHS EACH DAY IN THE LOW 80S ACROSS THE EAST COAST.
LONG RANGE MODELS INDICATE THAT THE DRY PATTERN WILL CONTINUE
ACROSS THE AREA INTO THE FIRST PART OF NEXT WEEK WITH NORTHEAST
SURFACE FLOW PREVAILING.
MARINE...
LIGHT SOUTH-SOUTHWEST WINDS WILL CONTINUE THROUGH TONIGHT AHEAD OF
AN APPROACHING COLD FRONT. SCATTERED SHOWERS DEVELOPING OUT AHEAD
OF THIS BOUNDARY WILL REMAIN POSSIBLE THROUGH THE MID-WEEK TIME
FRAME. DRIER AIR ALONG WITH INCREASING WINDS AND SEAS ARE FORECAST
TO SPREAD SOUTH OVER THE MARINE AREAS IN THE WAKE OF THE FRONT
BEGINNING THURSDAY AND CONTINUING INTO THE UPCOMING WEEKEND.
AVIATION...
MAINLY VFR CONDITIONS ARE EXPECTED FOR ALL SOUTH FLORIDA
TERMINALS EARLY THIS MORNING. THERE COULD BE SOME PATCHY
FOG OR AREAS OF FOG EARLY THIS MORNING...BUT MAINLY EXPECTED IN
THE INTERIOR REGIONS. BUT WILL AMEND AS NECESSARY. LIGHT
SOUTHEASTERLY FLOW PREVAILS ACROSS THE REGION BUT COULD BE LIGHT
AND VARIABLE AT THE TERMINALS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 72 87 73 / 30 30 50 30
FORT LAUDERDALE 87 76 87 74 / 20 20 50 40
MIAMI 88 75 87 75 / 20 20 50 40
NAPLES 88 73 87 71 / 20 30 50 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS WICHITA KS
712 AM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 712 AM CDT TUE OCT 22 2013
THIS MORNING:
THE PURPOSE FOR THE UPDATE IS TWO-FOLD:
1) TO REMOVE SPRINKLES FROM PARTS OF CENTRAL & SOUTH-CENTRAL KS.
2) TO ADJUST CLOUD COVER TO REFLECT SATELLITE TRENDS TO FOCUS
CLOUD COVER OVER SE KS THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
TODAY:
ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE
OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING
ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING.
OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT
RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND
POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS
AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE
FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES
WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY.
TONIGHT:
RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES
EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS
WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR
WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL
LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST
ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF
NEEDED.
WED-THU:
QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD
OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY.
TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN
HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS.
TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT
WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE
TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION
CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF
MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE
TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN
FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW
DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN
TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON
ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE
BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON
MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST
OF THE DAY. -HOWERTON
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 712 AM CDT TUE OCT 22 2013
EXCEPT FOR NW WINDS THAT WILL INCREASE TO 15-20KTS ~18Z ALL AREAS
TO SHOULD GOOD WEATHER WITH CLOUDINESS LIMITED TO ~8,000FT ALTOCU.
THE NW WINDS WILL QUICKLY DIMINISH EARLY THIS EVENING AS THEY SHIFT
SLOWLY TO THE N.
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 68 39 71 38 / 0 0 0 0
HUTCHINSON 67 38 69 37 / 0 0 0 0
NEWTON 65 38 69 36 / 0 0 0 0
ELDORADO 66 35 69 36 / 10 0 0 0
WINFIELD-KWLD 68 37 73 38 / 0 0 0 0
RUSSELL 66 37 67 34 / 0 0 0 0
GREAT BEND 66 37 68 34 / 0 0 0 0
SALINA 66 36 69 36 / 0 0 0 0
MCPHERSON 66 37 69 36 / 0 0 0 0
COFFEYVILLE 68 36 69 38 / 10 0 0 0
CHANUTE 67 33 65 35 / 10 0 10 0
IOLA 65 32 65 35 / 10 0 10 0
PARSONS-KPPF 67 33 67 34 / 10 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053-
069>072-094>096-099-100.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
747 AM EDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE OCT 22 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND
A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL
LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE
SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH
EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A
BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL
CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED
BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE
IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE
ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE.
WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE
RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET
BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE
BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE
EAST.
TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS
850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR
MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF
SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE
SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING
JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON.
TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO
THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN
850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND
BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR
LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL
INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR
LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EDT TUE OCT 22 2013
THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE
UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL
REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL
BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE
SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS
WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND
THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT
AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND
8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE
EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO
WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH
WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE
NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF
GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER
THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW
FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST).
WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA
LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE
LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR
THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE
LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO
BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A
QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE
TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED
CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE
EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP
PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO
WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS
AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR).
THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER
SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO
THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT
EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ.
THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN
THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN
ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE
AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO
EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO
1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE
SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL
ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER
BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS.
THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS
IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE
SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL
BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS
SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP.
ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT
PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN
PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT
AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE
EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT
NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA
AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS
TO LESSEN.
THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT
AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER
GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO
EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE
ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND
THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA.
FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH
THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING
SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO
SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE
EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION
OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE
NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT
THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST
WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL
HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN
GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER
TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS
LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A
REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST
TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE
DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST
COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED
FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE
AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES
WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE
TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 746 AM EDT TUE OCT 22 2013
EXPECT MVFR WX TO DOMINATE MOST OF THIS FCST PERIOD WITH COLD NW
FLOW BETWEEN A DEPARTING LOW PRESSURE TROOUGH AND AN INCOMING RIDGE.
THE CLOSER APPROACH OF THE SFC RIDGE AND WEAKER PRES GRADIENT LATER
TODAY WILL ALLOW GUSTY NW WINDS TO DIMINISH. AT SAW LAKE EFFECT SNOW
SHOWERS WILL DIMINISH EARLY TODAY AND THEN VFR WX WILL RETURN THIS
AFTERNOON AS THE RIDGE APPROACHES WHILE LAKE MOISTURE KEEPS MVFR
CIGS AT CMX/IWD WITH PREVAILING NW WINDS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE OCT 22 2013
NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY
AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH.
HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE
NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE
THROUGH THE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ005.
LAKE SUPERIOR...
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ264>267.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
713 AM EDT TUE OCT 22 2013
.AVIATION...
//DISCUSSION...
DRY WESTERLY FLOW SCOURED OUT EVEN THE LAKE EFFECT STRATOCU FROM
LAKE MICHIGAN BEFORE SUNRISE LEAVING CLEAR CONDITIONS TO START THE
DAY. SUNSHINE AND SURFACE HEATING WILL THEN HELP CLOUDS REDEVELOP
DURING THE LATE MORNING WITH A VFR CEILING BACK IN PLACE FOR THE
AFTERNOON. A FAST MOVING LOW PRESSURE SYSTEM WILL ARRIVE FROM THE
CENTRAL PLAINS OVER INDIANA AND OHIO BY LATE AFTERNOON THROUGH
THIS EVENING. THIS SYSTEM COULD PRODUCE LIGHT RAIN IN THE DTW
TERMINAL CORRIDOR THROUGH LATE EVENING BUT NO RESTRICTION IS
EXPECTED OTHER THAN A CEILING BELOW 5000 FEET. BACKING LOW LEVEL
FLOW AFTER MIDNIGHT WILL THEN HELP STRATOCU DIMINISH AGAIN TOWARD
SUNRISE WEDNESDAY OVER ALL TERMINAL SITES.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FEET AFTER 15Z TUESDAY
WITH HIGHER CONFIDENCE AFTER 00Z.
&&
.PREV DISCUSSION...ISSUED 347 AM EDT TUE OCT 22 2013
SHORT TERM... TODAY AND TONIGHT
CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL
MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR
MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED
ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND
POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW
LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM
THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO
SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS
TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE
LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO
THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO
SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT
WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS
RECOVER INTO THE MID AND UPPER 40S.
THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS
BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING
THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE
THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE
SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION
OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A
CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO
SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE
AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING
GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE
SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS
REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH
THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL
DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A
CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF
THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD
ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS
INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY
LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE
EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK
LOOK ON TARGET BY SUNRISE WEDNESDAY.
LONG TERM...
LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT
LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE
DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE
MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH
PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN
THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C.
IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS
TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN
WILL TEND TO BE SHUNTED TO OUR SOUTHWEST.
THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED
TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE
HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH
ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST
INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED
AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL
FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV
ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED
WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT
POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE
OHIO VALLEY.
MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE
SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER
CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO
PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS
NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR
CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING
WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S.
SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK
INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT
RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH
PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK
UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN
REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS
GRIP ON THE AREA.
MARINE...
A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY
WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL
LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT
GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN
THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE
SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP
WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE
WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON
TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH
TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND
WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE
WEEK.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM
TUESDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8
AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
SANILAC...UNTIL 8 AM WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....BT
SHORT TERM...BT
LONG TERM....JVC
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
611 AM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 611 AM CDT TUE OCT 22 2013
UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT TUE OCT 22 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE UPPER
LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA BEING SHUNTED
INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES DROP SOUTHEAST
THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE MAIN SHORTWAVE OF
INTEREST FOR THE SHORT TERM CAN BE SEEN OVER EASTERN SOUTH DAKOTA...
AND IS HELPING TO GENERATE THE LIGHT PCPN SEEN ON RADAR AND SURFACE
OBS OVER FAR SOUTHWEST MINNESOTA... EASTERN SOUTH DAKOTA... AND
NORTHERN IOWA. MOST OF THIS ACTIVITY LOOKS LIKE IT WILL REMAIN SOUTH
OF OUR AREA THIS MORNING... SO MAINLY JUST MENTIONED SOME FLURRIES
OR LOW POPS WITH NO SNOWFALL ACCUMULATIONS. OTHERWISE... TODAY LOOKS
BENIGN ACROSS THE FORECAST AREA... WITH SOME PEAKS OF SUN
INTERSPERSED WITH LINGERING STRATOCU. WE MAINTAIN SOMEWHAT OF A
925-850MB THERMAL TROUGH OVER THE AREA TODAY... WHICH SHOULD KEEP
PLENTY OF CLOUDS IN PLACE... AND LATEST 11-3.9 MICRON IMAGERY SHOWS
PLENTY OF CLOUDS TO THE NORTH DROPPING SOUTH WITH TIME. HOWEVER...
THERE ARE INDICATIONS THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE
ANTICYCLONIC THIS AFTERNOON... WHICH COULD WORK TO GENERATE SOME
DECENT BREAKS IN THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY
FOR NOW GIVEN SATELLITE TRENDS AND FORECAST PROFILES... AND WENT
WITH MOSTLY CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT
SHORTWAVE OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS
MORNING/S... AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT
INTO WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN
WILL ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL
MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER
THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND
FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY
SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH WILL
ONCE AGAIN BE QUITE A BIT BELOW NORMAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE OCT 22 2013
EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS
IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST COAST
OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES REGION.
THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP A CYCLONE
ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY COLD AIR WILL
CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST FOR THE NEXT
COUPLE OF DAYS.
MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN
MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY
THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN STREAM
TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE COAST OF NEW
FOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE NORTHERLY WINDS
CURRENTLY IN PLACE ACROSS THE REGION TO BECOME MORE WESTERLY BY THE
END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE WILL LEAD LEE SIDE
WARMING ON THE FOOTHILLS OF THE ROCKIES...AND THIS WARM AIR WILL
MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. IN
FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE
SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850. NOT EXACTLY
A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS. THIS WARM UP WILL
BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS LOW LEVEL WARM AIR
ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS SOUTHERN CANADA...AND
DRIVE A WEAK COLD FRONT THROUGH THE REGION. THIS FRONTAL BOUNDARY
WILL EVENTUALLY BECOME ORIENTED EAST/WEST...AND SET THE STAGE FOR A
POTENTIALLY SIGNIFICANT STORM SYSTEM TO DEVELOP NEXT WEEK OVER THE
MIDWEST.
IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP
MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO
MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE
SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW CLIMATOLOGY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 611 AM CDT TUE OCT 22 2013
MAIN AVIATION CONCERN IS STRATOCU ATTEMPTING TO SLIDE SOUTH INTO
THE AREA... WHICH IS CURRENTLY PRODUCING WIDESPREAD MVFR CEILINGS.
THE SHORTWAVE TO OUR SOUTHWEST IS PRODUCING SOME LIGHT PCPN... BUT
IT WILL STAY SOUTH OF TAF SITES... WITH SOME VFR CEILINGS BEING
THE ONLY THING IT SHOULD PRODUCE. CURRENT THINKING IS THAT THE
MVFR CEILINGS WILL DROP SOUTH ACROSS ALL BUT KRWF... BUT WILL THEN
START TO RISE THROUGH THE DAY... AND PROBABLY SCATTER OUT DURING
THE EVENING HOURS. HOWEVER... THERE IS A FAIR DEGREE OF
UNCERTAINLY ON HOW STUBBORN THE CLOUDS WILL BE... AND THERE/S A
CHANCE FOR SOME DECENT BREAKS TODAY BUT ALSO FOR THINGS TO STICK
AROUND LONGER TONIGHT.
KMSP...MAIN CONCERN IS WITH CEILINGS DROPPING IN FROM THE NORTH.
IT APPEARS THEY WILL PRODUCE MVFR CONDITIONS FOR A GOOD PART OF
THE DAY... BUT WILL BE ABOVE 017 SO IMPACTS SHOULD BE MINIMAL. THE
SCATTERING OUT ADVERTISED FOR TONIGHT COULD EASILY OCCUR SOONER OR
LATER BY SEVERAL HOURS WITH MUCH DEPENDING UPON HOW MUCH RESIDUAL
MOISTURE WINDS UP TRAPPED BENEATH A SUBSIDENCE INVERSION AND AT
WHAT LEVEL THAT INVERSION MANIFESTS.
/OUTLOOK FOR KMSP/
WEDNESDAY AFTERNOON THROUGH THURSDAY...VFR. NORTHWEST WIND AROUND 10KT.
THURSDAY NIGHT...VFR. NORTHWEST WIND AROUND 10 KT BECOMING WEST.
FRIDAY...VFR. WEST WIND 5 TO 10 KT BECOMING SOUTHWEST 15 TO 20 KT.
FRIDAY NIGHT...MVFR CEILINGS POSSIBLE LATE. SOUTHWEST WIND 10 TO
20 KT BECOMING WEST.
SATURDAY...MVFR CEILINGS POSSIBLE EARLY. NORTHWEST WIND 15 TO 20
KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...
SHORT TERM...
LONG TERM...JRB
AVIATION...
AREA FORECAST DISCUSSION
NWS HASTINGS NE
620 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT TUE OCT 22 2013
MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS
MORNING AND TEMPERATURES.
CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS
HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA
EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE
CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS
HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE.
MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH
THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE
THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID
DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS
THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE
AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF
THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM
MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE
MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND
PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL
BE THE EXTENT OF THE PRECIPITATION.
THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING
AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND
INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS
DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH
AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT
IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP
TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER
TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE
SOUTHWEST.
SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT
TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL
BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN
THE CLOUDS MOVE THROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 425 AM CDT TUE OCT 22 2013
BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES.
THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE
BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A
BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE
WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA
COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE
LONG TERM.
THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH
FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR
NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS
TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS
MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE
EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT
OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE
JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND
THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE
INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH
TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED
TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD
BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST
HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD
BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE
TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY
SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS
WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW
TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO
NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID
TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY
RISING BY THE OVERNIGHT HOURS.
TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE
REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE
ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL
SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN
ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT
SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A
NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED
SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST
TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY
STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR
ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD
FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG
IT TO OUR EAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM CDT TUE OCT 22 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH MAINLY MID
LEVEL CLOUDS IN AND OUT. WINDS ARE EXPECTED TO INCREASE DURING THE
DAY WITH THE STRONGEST WINDS LATE THIS MORNING INTO EARLY THIS
AFTERNOON. BY EVENING THE WINDS WILL START TO DIMINISH.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1026 AM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 952 AM CDT TUE OCT 22 2013
UPDATE FOR MINOR ADJUSTMENTS TO POPS THIS AFTERNOON AND TONIGHT.
HAVE DELAYED LIGHT RAIN IN THE FAR NORTHWEST UNTIL LATE AFTERNOON.
THE BULK OF THE PRECIPITATION IS EXPECTED AFTER 00Z THIS EVENING.
THE FAR SOUTHWEST SHOULD BE WARM ENOUGH IN THE LOW LEVELS TO
REMAIN MOSTLY RAIN...WHILE A SWATH OF LIGHT SNOW IS EXPECTED
MAINLY EAST OF HIGHWAY 22. ACCUMULATIONS SHOULD BE UNDER AN INCH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT TUE OCT 22 2013
MAIN CONCERN IN THE SHORT TERM FORECAST PERIOD WILL BE MORE
PRECIPITATION CHANCES LATER THIS AFTERNOON / TONIGHT.
EARLY MORNING RADAR MOSAIC SHOWED LIGHT RETURNS MOVING ACROSS
SOUTH CENTRAL NORTH DAKOTA. THE OVERALL TREND HAS BEEN FOR THE
AREA OF PRECIPITATION TO DIMINISH OVER THE PAST COUPLE HOURS AND
THIS IS IN LINE WITH MOST SHORT TERM MODEL SOLUTIONS.
THE NEXT UPPER WAVE ARRIVES LATER THIS AFTERNOON / TONIGHT.
THE NAM / GFS SUGGEST THE STRONGER FORCING WILL NOT ARRIVE UNTIL
AFTER 18Z AND WILL DELAY POPS ACCORDINGLY. THE PRECIPITATION CHANCES
SHOULD SPREAD FROM NORTHWEST TO SOUTHEAST IN CONCERT WITH THE BEST
FORCING / VERTICAL MOTION...AND THIS TREND IS ALREADY WELL COVERED
IN THE POP GRIDS. THERMAL PROFILES AGAIN SUGGEST EITHER RAIN OR
SNOW WILL BE THE MAIN PRECIPITATION TYPES. SIMILAR TO MONDAY...HAVE
USED 35F AS THE ALL SNOW THRESHOLD TRANSITIONING TO RAIN AT 38F.
SNOW AMOUNTS WILL GENERALLY STAY LESS THAN HALF AN INCH.
LOOKING AT TEMPERATURES...HAVE KEPT HIGHS FOR TODAY WELL BELOW
NORMAL AGAIN. WILL GO WITH MID 30S TO NEAR 40 EAST...TO MID 40S TO
LOW 50S WEST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 309 AM CDT TUE OCT 22 2013
THE PERSISTENT NORTHWEST FLOW ALOFT INDUCED BY AN UPPER RIDGE ACROSS
THE ROCKIES AND A LONGWAVE TROUGH IN SOUTHEAST CANADA AND INTO THE
GREAT LAKES/OHIO VALLEY WILL LIFT NORTHEAST THROUGH THE PERIOD. THIS
WILL SHIFT THE MAIN JET AND PROLONGED PERIOD OF UPPER SHORTWAVES
FURTHER EAST THURSDAY THROUGH SATURDAY. WARM AIR ADVECTION WILL
INCREASE FRIDAY AND SATURDAY...AHEAD OF THE NEXT ALBERTA CLIPPER
WHICH IS SLATED FOR SUNDAY AFTERNOON INTO MONDAY. MUCH COLDER
TEMPERATURES BEHIND THE CLIPPER ARE FORECAST FOR MONDAY AND TUESDAY.
FOR WEDNESDAY...A SHORTWAVE WILL SLIDE SOUTHEAST ACROSS THE TURTLE
MOUNTAINS AND INTO THE JAMES RIVER VALLEY BY AFTERNOON. A CHANCE FOR
MAINLY SNOW SHOWERS IN THE MORNING AND A RAIN/SNOW MIX POSSIBLE IN
THE AFTERNOON IN THE FAR SOUTH AS THE WAVE DEPARTS. COLD H85 AIR IN
THE TURTLE MOUNTAINS AND ACROSS EAST CENTRAL NORTH DAKOTA MAY YIELD
FLURRIES OR A SNOW SHOWER WEDNESDAY AFTERNOON.
FOR THURSDAY THROUGH SATURDAY...NORTHWEST FLOW RELAXES AS THE
STRONGEST HEIGHT GRADIENT SHIFTS EAST. A BRIEF TRANSITION TO WARM
AIR ADVECTION COMMENCES FRIDAY AND MAINTAINS A PRESENCE INTO SUNDAY.
WILL MAINTAIN A DRY FORECAST DURING THIS TIME WITH A MODERATING
TREND FRIDAY AS HIGHS WILL RISE INTO THE 50S MOST AREAS EXCEPT IN
THE TURTLE MOUNTAINS. EXPECT HIGHS IN THE 40S TO LOWER 50S SATURDAY
AND SUNDAY.
FOR SUNDAY AFTERNOON THROUGH MONDAY...A POTENT ALBERTA CLIPPER WILL
MAKE ITS WAY INTO WESTERN/CENTRAL NORTH DAKOTA. H85 TEMPS TAKE A
DIGGER FROM AROUND +8C SUNDAY AFTERNOON TO -10C MONDAY AFTERNOON.
UNCERTAINTY AT THIS TIME REVOLVES AROUND PRECIPITATION TOTALS. BOTH
THE GFS AND ECMWF ADVERTISE MOSTLY POST FRONTAL PRECIPITATION/SNOW.
THE DIFFERENCE IS THAT THE ECMWF IS MORE AGGRESSIVE IN AMOUNTS AND
IS SLOWEST TO MOVE THROUGH...WHILE THE GFS IS QUICKEST AND LESS
ROBUST. AT THIS TIME...JUST LOOKING AT SNOWFALL AMOUNTS THE GFS
WOULD PROBABLY NOT WARRANT WINTER WEATHER HEADLINES BUT THE ECMWF
WOULD. CONSIDERING OVERALL IMPACTS...ENOUGH EVIDENCE IN BOTH MODELS
FOR A WINTER HEADLINE. WILL TAKE A SLOW APPROACH AND BEGIN TO
ADVERTISE THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. WILL MONITOR
AND ADJUST IN THE COMING DAYS AS THE LONG RANGE MODELS COME INTO
BETTER AGREEMENT. TUESDAY LOOKS DRY BUT REMAINS COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 615 AM CDT TUE OCT 22 2013
A WIDE VARIETY OF CONDITIONS EXIST EARLY THIS MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. EVERYTHING FROM IFR TO VFR IS
BEING REPORTED. IT APPEARS THE IFR CONDITIONS ARE TIED TO A
FRONTAL BOUNDARY LOCATED FROM NORTHWEST NORTH DAKOTA INTO CENTRAL
SOUTH DAKOTA. THE LATEST HRRR SUGGESTS A MAJORITY OF THE IFR
CONDITIONS SHOULD NOT MOVE MUCH THIS MORNING BEFORE A GRADUAL
IMPROVING TREND TAKES HOLD. WILL STAY WITH MVFR OR VFR THIS
MORNING...AND SHOW SOME IMPROVEMENT INTO THE AFTERNOON. ANOTHER
CHANCE OF PRECIPITATION ARRIVES THIS AFTERNOON NEAR KISN...THEN
SPREADS SOUTHEAST TONIGHT. WILL TREND TO MVFR AGAIN AS THE
PRECIPITATION SPREADS ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RP KINNEY
SHORT TERM...CK
LONG TERM...KS
AVIATION...CK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
615 AM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 615 AM CDT TUE OCT 22 2013
LATEST FOG/STRATUS SHOWS IFR/MVFR CIGS WITH PATCHY FOG ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. STATIONARY FRONTAL SYSTEM
STRETCHED FROM NEAR MOOSE JAW CANADA...TO TIOGA AND GLEN ULLIN
AND INTO PIERRE SOUTH DAKOTA. VERY WEAK RADAR RETURNS SHOWING UP
NEAR AND ALONG THIS CONVERGENCE ZONE. THE CURRENT FORECAST HAS
THIS HANDLED WELL AND ONLY MINOR UPDATES TO HOURLY SENSIBLE
WEATHER ELEMENTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT TUE OCT 22 2013
MAIN CONCERN IN THE SHORT TERM FORECAST PERIOD WILL BE MORE
PRECIPITATION CHANCES LATER THIS AFTERNOON / TONIGHT.
EARLY MORNING RADAR MOSAIC SHOWED LIGHT RETURNS MOVING ACROSS
SOUTH CENTRAL NORTH DAKOTA. THE OVERALL TREND HAS BEEN FOR THE
AREA OF PRECIPITATION TO DIMINISH OVER THE PAST COUPLE HOURS AND
THIS IS IN LINE WITH MOST SHORT TERM MODEL SOLUTIONS.
THE NEXT UPPER WAVE ARRIVES LATER THIS AFTERNOON / TONIGHT.
THE NAM / GFS SUGGEST THE STRONGER FORCING WILL NOT ARRIVE UNTIL
AFTER 18Z AND WILL DELAY POPS ACCORDINGLY. THE PRECIPITATION CHANCES
SHOULD SPREAD FROM NORTHWEST TO SOUTHEAST IN CONCERT WITH THE BEST
FORCING / VERTICAL MOTION...AND THIS TREND IS ALREADY WELL COVERED
IN THE POP GRIDS. THERMAL PROFILES AGAIN SUGGEST EITHER RAIN OR
SNOW WILL BE THE MAIN PRECIPITATION TYPES. SIMILAR TO MONDAY...HAVE
USED 35F AS THE ALL SNOW THRESHOLD TRANSITIONING TO RAIN AT 38F.
SNOW AMOUNTS WILL GENERALLY STAY LESS THAN HALF AN INCH.
LOOKING AT TEMPERATURES...HAVE KEPT HIGHS FOR TODAY WELL BELOW
NORMAL AGAIN. WILL GO WITH MID 30S TO NEAR 40 EAST...TO MID 40S TO
LOW 50S WEST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 309 AM CDT TUE OCT 22 2013
THE PERSISTENT NORTHWEST FLOW ALOFT INDUCED BY AN UPPER RIDGE ACROSS
THE ROCKIES AND A LONGWAVE TROUGH IN SOUTHEAST CANADA AND INTO THE
GREAT LAKES/OHIO VALLEY WILL LIFT NORTHEAST THROUGH THE PERIOD. THIS
WILL SHIFT THE MAIN JET AND PROLONGED PERIOD OF UPPER SHORTWAVES
FURTHER EAST THURSDAY THROUGH SATURDAY. WARM AIR ADVECTION WILL
INCREASE FRIDAY AND SATURDAY...AHEAD OF THE NEXT ALBERTA CLIPPER
WHICH IS SLATED FOR SUNDAY AFTERNOON INTO MONDAY. MUCH COLDER
TEMPERATURES BEHIND THE CLIPPER ARE FORECAST FOR MONDAY AND TUESDAY.
FOR WEDNESDAY...A SHORTWAVE WILL SLIDE SOUTHEAST ACROSS THE TURTLE
MOUNTAINS AND INTO THE JAMES RIVER VALLEY BY AFTERNOON. A CHANCE FOR
MAINLY SNOW SHOWERS IN THE MORNING AND A RAIN/SNOW MIX POSSIBLE IN
THE AFTERNOON IN THE FAR SOUTH AS THE WAVE DEPARTS. COLD H85 AIR IN
THE TURTLE MOUNTAINS AND ACROSS EAST CENTRAL NORTH DAKOTA MAY YIELD
FLURRIES OR A SNOW SHOWER WEDNESDAY AFTERNOON.
FOR THURSDAY THROUGH SATURDAY...NORTHWEST FLOW RELAXES AS THE
STRONGEST HEIGHT GRADIENT SHIFTS EAST. A BRIEF TRANSITION TO WARM
AIR ADVECTION COMMENCES FRIDAY AND MAINTAINS A PRESENCE INTO SUNDAY.
WILL MAINTAIN A DRY FORECAST DURING THIS TIME WITH A MODERATING
TREND FRIDAY AS HIGHS WILL RISE INTO THE 50S MOST AREAS EXCEPT IN
THE TURTLE MOUNTAINS. EXPECT HIGHS IN THE 40S TO LOWER 50S SATURDAY
AND SUNDAY.
FOR SUNDAY AFTERNOON THROUGH MONDAY...A POTENT ALBERTA CLIPPER WILL
MAKE ITS WAY INTO WESTERN/CENTRAL NORTH DAKOTA. H85 TEMPS TAKE A
DIGGER FROM AROUND +8C SUNDAY AFTERNOON TO -10C MONDAY AFTERNOON.
UNCERTAINTY AT THIS TIME REVOLVES AROUND PRECIPITATION TOTALS. BOTH
THE GFS AND ECMWF ADVERTISE MOSTLY POST FRONTAL PRECIPITATION/SNOW.
THE DIFFERENCE IS THAT THE ECMWF IS MORE AGGRESSIVE IN AMOUNTS AND
IS SLOWEST TO MOVE THROUGH...WHILE THE GFS IS QUICKEST AND LESS
ROBUST. AT THIS TIME...JUST LOOKING AT SNOWFALL AMOUNTS THE GFS
WOULD PROBABLY NOT WARRANT WINTER WEATHER HEADLINES BUT THE ECMWF
WOULD. CONSIDERING OVERALL IMPACTS...ENOUGH EVIDENCE IN BOTH MODELS
FOR A WINTER HEADLINE. WILL TAKE A SLOW APPROACH AND BEGIN TO
ADVERTISE THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. WILL MONITOR
AND ADJUST IN THE COMING DAYS AS THE LONG RANGE MODELS COME INTO
BETTER AGREEMENT. TUESDAY LOOKS DRY BUT REMAINS COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 615 AM CDT TUE OCT 22 2013
A WIDE VARIETY OF CONDITIONS EXIST EARLY THIS MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. EVERYTHING FROM IFR TO VFR IS
BEING REPORTED. IT APPEARS THE IFR CONDITIONS ARE TIED TO A
FRONTAL BOUNDARY LOCATED FROM NORTHWEST NORTH DAKOTA INTO CENTRAL
SOUTH DAKOTA. THE LATEST HRRR SUGGESTS A MAJORITY OF THE IFR
CONDITIONS SHOULD NOT MOVE MUCH THIS MORNING BEFORE A GRADUAL
IMPROVING TREND TAKES HOLD. WILL STAY WITH MVFR OR VFR THIS
MORNING...AND SHOW SOME IMPROVEMENT INTO THE AFTERNOON. ANOTHER
CHANCE OF PRECIPITATION ARRIVES THIS AFTERNOON NEAR KISN...THEN
SPREADS SOUTHEAST TONIGHT. WILL TREND TO MVFR AGAIN AS THE
PRECIPITATION SPREADS ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...CK
LONG TERM...KS
AVIATION...CK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
618 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE
ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION
GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR
AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN
SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD
EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A
HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES
EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE
MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES
BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON
HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS
UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S.
ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER
TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM
WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING
HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES
WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT
BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER
THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE
TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF
AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD
THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE
CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF
HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q
VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY
OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF
AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN
ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA
OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY
LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW
WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING
TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST
OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST
CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR
TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA
OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE
AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME
TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP
WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND
11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL
REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF
HIGHS ONLY IN THE 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS
TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO
WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY.
ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST
THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS
SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION
AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY
LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL...
WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE
PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND
THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH
HIGHS THURSDAY AGAIN IN THE 40S.
LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE
NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY
NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS
SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT
OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL
CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A
COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING
BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF
OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A
FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA
TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD
HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS
AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK.
MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN
ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER
PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 612 AM CDT TUE OCT 22 2013
AREA OF LIGHT RAIN AND SNOW WILL DISSIPATE AND EXIT THE AREA BY LATE
MORNING. CIGS IN THE LIFR TO MVFR RANGE WILL SLOWLY LIFT THROUGH THE
MORNING...AND SHOULD BECOME VFR BY MID TO LATE AFTERNOON. BRIEF
VISIBILITY REDUCTIONS INTO THE 2SM TO 4SM RANGE WILL BE POSSIBLE IN
SNOW THROUGH MID MORNING AS WELL. VFR CONDITIONS SHOULD PREVAIL MOST
OF TONIGHT. HOWEVER...ANOTHER LOW PRESSURE SYSTEM WILL BRING A RETURN
TO THE LIGHT RAIN OR SNOW THREAT LATE TONIGHT INTO WEDNESDAY MORNING.
AGAIN WOULD EXPECT CIGS TO DROP WITH THIS FEATURE. FOR NOW KEPT THE
TAFS MVFR AT KHON AND VFR AT KFSD AND KSUX GIVEN UNCERTAINTY OF
TIMING AND PLACEMENT OF PRECIPITATION SHIELD. ALTHOUGH WOULD EXPECT
CIGS TO LOWER INTO THE MVFR TO IFR RANGE AT SOME POINT LATE TONIGHT OR
EARLY WEDNESDAY WHERE THE AREA OF PRECIPITATION MOVES ACROSS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JH
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
609 AM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT TUE OCT 22 2013
AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA
NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED
IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD
OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO
MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K
ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST
AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS
RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES
IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A
VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DEDRITIC
GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF
DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS
SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT
CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT
COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE
BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH
OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF
A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN.
FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5
C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS
WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 AM CDT TUE OCT 22 2013
ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE
TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A
RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC
LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH
LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN
30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF
NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND
THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER
EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT
THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN.
AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF
COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES
TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK
TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE
OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO
KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR
FRIDAY NIGHT INTO SATURDAY.
LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT
THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE
TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS...
THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS
WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS
COULD BE OUR FIRST TASTE OF INDIAN SUMMER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 608 AM CDT TUE OCT 22 2013
CLOUD SHIELD ASSOCIATED WITH THE AREA OF LOW PRESSURE OVER
NEBRASKA HAS FOR THE MOST PART STAYED TO THE SOUTH OF BOTH TAF
SITES. HIGHER LEVEL CLOUDS ARE MAKING SLOW EASTWARD PROGRESS AND
ARE EXPECTED TO SPREAD ACROSS BOTH TAF SITES THROUGH THE MORNING.
AS THE DAY PROGRESSES AND THE SURFACE LOW MOVES ACROSS IOWA TOWARD
ILLINOIS...IT IS EXPECTED TO START PULLING DOWN THE LOW LEVEL
MOISTURE IN PLACE OVER NORTHERN MINNESOTA AND WISCONSIN. THIS
SHOULD INITIALLY RESULT IN VFR CEILINGS THIS AFTERNOON AND
EVENTUALLY GOING TO MVFR DURING THE EVENING. SOMEWHAT CONCERNED
THAT THE CEILINGS COULD GO MVFR THIS AFTERNOON AS THESE CURRENTLY
RESIDE OVER NORTHERN WISCONSIN INTO CENTRAL MINNESOTA.
HOWEVER...THINK THE MIXED LAYER WILL GET DEEP ENOUGH BEFORE THE
MOISTURE ARRIVES TO MAKE THE INITIAL CEILINGS BE VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1035 AM MDT TUE OCT 22 2013
.UPDATE...
&&
.SHORT TERM...ONGOING FORECASTS LOOK GOOD. BATCH OF MID LEVEL
CLOUD OVER FAR NORTHEAST COLORADO MOVING SOUTHEAST. NEXT BATCH
OVER EASTERN WYOMING AND WESTERN NEBRASKA ALSO HEADING
SOUTHEAST...SHOULD BE CLIPPING THE NORTHEAST CORNER AROUND 18Z.
OTHERWISE...MAINLY CLEAR SKIES TO PREVAIL THROUGH THE AFTERNOON
AND EVENING. FORECAST SOUNDINGS AND THICKNESS PROGS SUGGEST HIGHS
ACROSS PLAINS TO WARM INTO THE 60S. ONLY MINOR TWEAKS TO
TEMPERATURE GRIDS AT THIS TIME.
.AVIATION...CURRENT TAF TRENDS SEEM ON TRACK. LIGHT SOUTHEAST
WINDS TO SHIFT TO THE NORTHEAST AROUND 19Z...THEN BACK TO
SOUTHEAST AT 23Z. SLIGHT CHANCE OF AN ANTICYCLONE DEVELOPING NEAR
THE DENVER AREA WHICH MAY KEEP WINDS SOUTHEAST THROUGH THE
AFTERNOON...LATEST HRRR AND RAP SHOW THIS FEATURE FAIRLY WEAK.
WILL MAINTAIN THE CURRENT TAF SOLUTION. VFR CONTINUES.
&&
.PREV DISCUSSION... /ISSUED 403 AM MDT TUE OCT 22 2013/
SHORT TERM...CURRENT SATELLITE IMAGERY SHOWS MID LEVEL CLOUD DECK
STILL HOLDING OVER THE NORTHEAST PLAINS. HOWEVER...THERE ARE SIGNS
OF EROSION FROM THE NORTHWEST AS UPSTREAM CLOUD BAND EXTENDING
INTO WYOMING WAS BEGINNING TO BREAK UP. AS A RESULT...EXPECT THE
NEARLY OVERCAST SKIES OVER THE NORTHEASTERN PLAINS TO SEE A
GRADUAL EROSION THROUGH THE MORNING HOURS LEAVING BEHIND MOSTLY
SUNNY SKIES BY AFTERNOON. FROM THE FRONT RANGE URBAN CORRIDOR
WESTWARD ACROSS THE MOUNTAINS...SKIES WILL BE MOSTLY SUNNY
THROUGH THE ENTIRE DAY. WARM ADVECTION WAS UNDERWAY AND WE EXPECT
ABOUT 4C WARMING FROM YESTERDAY. THIS ALONG WITH A WARMER START TO
THE DAY WILL HELP PUSH HIGHS CLOSE TO 10 DEGREES F WARMER. TODAY
WILL BE OUR FIRST DAY WITH AN ABOVE NORMAL HIGH SINCE OCT 13TH.
FOR TONIGHT...MOSTLY CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW FOR
BETTER RADIATIONAL COOLING AND LOW TEMPS CLOSER TO NORMAL.
LONG TERM...A VERY STABLE RIDGE/TROUGH UPPER AIR PATTERN WILL
REMAIN IN POSITION OVER THE COUNTRY THROUGH THE END OF THE WEEK...
LEAVING COLORADO HIGH AND DRY THROUGH THE FORECAST PERIOD. LIGHT
TO MODERATE NORTHWESTERLY FLOW ALOFT WILL CONTINUE AS THE WESTERN
U.S. UPPER RIDGE IS HELD IN PLACE BY A DEEP TROUGH OVER THE GREAT
LAKES AND EASTERN CANADA. FOR WEDNESDAY AND THURSDAY...
TEMPERATURES WILL BE AROUND SEASONAL NORMALS...BUT THEN WARMER
TEMPERATURES ARE EXPECTED FOR THE WEEKEND. DRY CONDITIONS WILL
PREVAIL ACROSS THE FORECAST AREA.
A CHANGE IN THE UPPER PATTERN LOOKS TO BE IN THE OFFING FOR THE
FIRST PART OF NEXT WEEK. MODELS ARE OFFERING A PLETHORA OF
SOLUTIONS FOR NEXT MONDAY AFTERNOON. THE GFS OPERATIONAL RUN
SPREADS A STRONG PUSH OF CANADIAN AIR ACROSS THE NORTHERN AND
CENTRAL ROCKIES...WHILE THE ECMWF DEVELOPS A MORE CLOSED SYSTEM
OVER THE GREAT BASIN WHICH WOULD DELAY ANY COLD AIR MOVING INTO
COLORADO UNTIL THE UPPER LOW MOVES OVER THE STATE. IT IS HARD TO
TELL WHICH SOLUTION IS GOING TO BE RIGHT...SO FOR THE TIME BEING
WILL STICK WITH A SLIGHT CHANCE OF RAIN AND SNOW OVER THE FORECAST
AREA ON MONDAY WITH COOLER TEMPERATURES THAN OVER THE WEEKEND.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. SLIGHTLY
ENHANCED DRAINAGE WEST/SOUTHWEST WINDS THIS MORNING WILL MOST
LIKELY TRANSITION TO LIGHT/VARIABLE BY 15Z-17Z...NORTHEAST BY
19Z-20Z...AND THEN SOUTHEAST BY 23Z-01Z. SPEEDS AFTER 15Z WILL BE
AROUND 10KTS OR LESS. THERE IS A CHANCE OF AN ANTICYCLONE
DEVELOPING WHICH WOULD PRODUCE A MORE SOUTHEASTERLY COMPONENT
DURING THE AFTERNOON. KBJC MAY SEE A FEW WESTERLY GUSTS TO AROUND
20KTS TIL 15Z.
HYDROLOGY...NO PRECIPITATION WILL OCCUR THROUGH THIS WEEKEND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MIAMI FL
246 PM EDT TUE OCT 22 2013
.SHORT TERM (TONIGHT-THURSDAY NIGHT)...
THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY
SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS CONTINUING TO INITIATE
ACROSS PORTIONS OF THE AREA...THEN BECOMING CONCENTRATED OVER THE
NORTHEASTERN SECTIONS OF THE AREA OR AROUND THE LAKE REGION TO THE
PALM BEACH COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS
BEFORE DIMINISHING. THE LATEST SHORT-RANGE MODEL GUIDANCE HAS
INITIALIZED WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY
INDICATES THE ABOVE AVERAGE TEMPERATURES PERSISTING THROUGH
WEDNESDAY AS A COLD FRONT APPROACHES AND MOVES INTO THE LOCAL AREA.
OVERNIGHT LOWS ARE FORECAST TO DROP INTO THE 70S TONIGHT AND RETURN
TO THE MID TO UPPER 80S THROUGH THE AFTERNOON PERIOD
WEDNESDAY...WHICH IS AROUND 3-5 DEGREES WARMER THAN AVERAGE FOR THIS
PERIOD. MODEL SOUNDINGS AROUND THE LOCAL AREA INDICATE THE DEEP
SOUTHWEST FLOW ALONG WITH INCREASING DEEP LAYER MOISTURE CONTINUING
AHEAD OF THE SHORTWAVE TROUGH CURRENTLY MOVING OVER THE MS VALLEY
REGION. UPPER HEIGHTS WILL BEGIN TO FALL LATER TONIGHT THROUGH THE
END OF THE PERIOD AS THIS UPPER TROUGH APPROACHES AND MOVES OVER THE
EAST COAST. THE FRONTAL BOUNDARY IS FORECAST TO PUSH THROUGH THE
LOCAL AREA THROUGH THE DAY WEDNESDAY WITH THE LOW-LEVEL WINDS
FORECAST TO QUICKLY VEER AND INCREASE OUT OF THE NORTHEAST WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT. NORTHEAST WINDS WILL LIKELY BECOME
GUSTY THROUGH THIS TIME THURSDAY...ESPECIALLY OVER THE ADJACENT
MARINE AREAS AND ALONG THE EAST COAST. ALTHOUGH MUCH DRIER AND
COOLER AIR WILL BEGIN TO SPREAD SOUTH INTO PORTIONS OF THE AREA
THROUGH THE DAY THURSDAY...THE RAIN CHANCES WILL REMAIN UP OVER THE
SOUTHERN HALF OF THE LOCAL AREA WHERE MODEL PWATS REMAIN AROUND THE
2" MARK. IN ADDITION TO THE RAIN CHANCES THURSDAY...SOME TSTMS WILL
REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY OVER THESE
SOUTHERN AREAS.
.LONG TERM (FRIDAY-MONDAY)...
MODELS REMAIN IN AGREEMENT WITH A SECONDARY FRONT SURGING THROUGH
THE AREA FRIDAY BRINGING A MUCH DRIER AIR MASS INTO SOUTH FLORIDA
ALONG WITH BELOW NORMAL TEMPERATURES. FAIRLY WIDESPREAD 50S SHOULD
BE SEEN ACROSS INTERIOR AREAS BOTH SATURDAY AND SUNDAY MORNINGS
WITH HIGHS EACH DAY IN THE LOW 80S ACROSS THE EAST COAST.
LONG-RANGE MODELS INDICATE THAT THE DRY PATTERN WILL CONTINUE
ACROSS THE AREA INTO THE FIRST PART OF NEXT WEEK WITH NORTHEAST
SURFACE FLOW PREVAILING.
&&
.AVIATION...18Z TAFS OCT. 13 2013
CURRENTLY HAVE A FEW SHRA MOVING NNE ALONG THE EAST COAST SEA BREEZE
AND THIS TREND WILL LIKELY TO CONTINUE THROUGH THE AFTERNOON WITH
ADDITIONAL DEVELOPMENT OVER INLAND AREAS. THERE COULD ALSO BE A TSRA
OR TWO BUT OVERALL CONFIDENCE AND COVERAGE TOO LOW TO PLACE IN THE
FORECAST AT THIS TIME. SOME OF THE ACTIVITY COULD PERSIST INTO THE
EVENING, HOWEVER THE HRRR HINTS AT LITTLE ACTIVITY PAST 00Z. SOME
LOCATIONS COULD HAVE VERY BRIEF MVFR OR EVEN IFR BUT TIMING AND
EXACT LOCATION WITH LOW COVERAGE ALWAYS DIFFICULT TO FORECAST SO
LEFT LIMITED RESTRICTIONS FOR NOW AND WILL AMEND IF NECESSARY. MOST
OF THE CONVECTION WILL BE WELL EAST OF KAPF UNTIL LATER IN THE
FORECAST WHEN THE FRONT SHIFTS SOUTH AND MAY HAVE AN INCREASE IN
SHRA OVER THE GULF WATERS AFT 06Z.
KOB
&&
.MARINE...
LIGHT SOUTH-SOUTHEAST WINDS WILL SHIFT TO THE SOUTH-
SOUTHWEST LATER TONIGHT AHEAD OF AN APPROACHING COLD FRONT.
SCATTERED SHOWERS DEVELOPING OUT AHEAD OF THIS BOUNDARY WILL
REMAIN POSSIBLE THROUGH THE MID-WEEK TIME FRAME. DRIER AIR ALONG
WITH INCREASING WINDS AND SEAS ARE FORECAST TO SPREAD SOUTH OVER
THE MARINE AREAS IN THE WAKE OF THE FRONT BEGINNING THURSDAY AND
CONTINUING INTO THE UPCOMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 70 81 / 30 50 40 20
FORT LAUDERDALE 77 87 73 82 / 30 40 40 30
MIAMI 75 88 72 82 / 30 40 40 40
NAPLES 74 87 66 84 / 30 40 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
238 PM CDT TUE OCT 22 2013
.DISCUSSION...
1035 AM CDT
RATHER IMPRESSIVE SYSTEM CONTINUES TO PUSH PRECIP TOWARD THE
FORECAST AREA LATE THIS MORNING. SURFACE ANALYSIS SHOWS LOW
PRESSURE CENTERED NEAR OR JUST NORTH OF KIRKSVILLE MISSOURI WITH
PRESSURE FALLS SUPPORTING A EAST-SOUTHEAST MOVEMENT OVER THE NEXT
FEW HOURS. WATER VAPOR IMAGERY SHOWS THE UPPER TROUGH/VORT MOVING
EASTWARD INTO NORTH CENTRAL ILLINOIS WHILE RADAR IMAGERY SHOWS A
BAND OF PRECIP WORKING EASTWARD ACROSS THE QUAD CITIES AND
EXTENDING SOUTHWARD DOWN THE MISSISSIPPI RIVER VALLEY. THE BULK OF
THE PRECIP SHIELD LINES UP WITH WITH NEAR TERM DEPICTIONS OF
850-700 MB FRONTOGENESIS ACROSS FAR EASTERN IOWA INTO WESTERN
ILLINOIS. RECENT OBS/WEBCAMS/REPORTS SHOW THAT MODERATE TO EVEN
HEAVY SNOW IS FALLING OVER THE QUAD CITIES WITH SEVERAL INCHES
QUICKLY ACCUMULATING ON GRASSY SURFACES/CARS/ROOFTOPS. THE CUTOFF
TO RAIN OCCURS PRETTY QUICKLY JUST SOUTH AND EAST OF THE QUAD
CITIES. ANOTHER BAND OF LIGHTER REFLECTIVITY EXTENDS FROM VINTON
IOWA EAST TO SAVANNA TO ROCHELLE AND NEAR DEKALB WHICH HAS BEEN A
MIX OF SNOW TO THE WEST WITH ROCHELLE NOW COMING IN WITH LIGHT
RAIN. THIS AREA IS FORCED FROM A HIGHER LEVEL...LINING UP WELL
WITH 700-600 MB FGEN. CLOUD BASES ARE STILL PRETTY HIGH WITH THIS
AREA SUGGESTING DRY AIR IS INHIBITING PRECIP FROM MAKING IT TO THE
GROUND BUT THIS FORCING IS EXPECTED TO REMAIN ORGANIZED AS IT
SHIFTS EASTWARD AND EVENTUALLY SLIGHTLY NORTHEASTWARD OVER
SOUTHERN LAKE MICHIGAN BY LATE AFTERNOON. EXPECT THAT SOME LIGHT
PRECIP...PROBABLY MOSTLY RAIN WILL FALL FROM THIS AREA INTO THE
MID AFTERNOON AFFECTING AREAS ALONG/NORTH OF THE INTERSTATE
88/INTERSTATE 290 CORRIDOR.
AS FOR THE MAIN BAND OF PRECIP...FGEN WILL CONTINUE TO SHIFT
EASTWARD AND FOCUS OVER THE CENTRAL/SOUTHERN CWA THROUGH THE
AFTERNOON. OVERALL AREA OF POPS FROM THE EARLIER FORECAST STILL
LOOKS GOOD FOCUSING THEM ALONG AND SOUTH OF INTERSTATE 80 WHICH
LATEST RADAR TRENDS ALSO SUPPORT. PRECIP TYPE WILL REMAIN THE
CHALLENGE WITH THE NARROW CORRIDOR OF MODERATE/HEAVY SNOW
CURRENTLY OCCURRING LIKELY TRANSLATING EASTWARD TOWARD THE WESTERN
CWA TOWARD EARLY AFTERNOON. TEMPS HAVE WARMED TO AROUND 40 BUT
WITH EVAPORATIVE COOLING AND THE INTENSE PRECIP TEMPS WILL LIKELY
FALL BACK INTO THE LOW/MID 30S AS THE BAND ARRIVES ASSUMING IT
MAINTAINS INTENSITY. THE MOST LIKELY AREA FOR SNOW LOOKS TO BE
RIGHT ALONG AND JUST SOUTH OF INTERSTATE 80 ACROSS SOUTHERN
LASALLE AND GRUNDY COUNTIES AND ALONG THE WILL/KANKAKEE BORDER
AREA GIVEN THAT TEMPS MAY REMAIN JUST COLD ENOUGH WITH PRECIP
INDUCED COOLING TO MAINTAIN SNOW. GRASSY AREAS WOULD BE THE MAIN
AREA OF ACCUMULATION WITH SOME BRIEF SLUSH ACCUMULATION ON LESS
TRAVELLED ROADWAYS POSSIBLE. UNFORTUNATELY...THERE IS STILL MUCH
UNCERTAINTY IN IF ALL SNOW WILL OCCUR FOR ANY LENGTH OF TIME GIVEN
THE MARGINAL TEMPS ETC. AHEAD OF THE PRECIP BUT THE ABOVE OUTLINED
AREA LOOKS MOST SUSCEPTIBLE. AREAS FURTHER SOUTH LOOK TO BE RAIN.
MDB
//PREV DISCUSSION...
343 AM CDT
USUALLY IT WOULD BE ANOTHER FEW WEEKS OR EVEN LONGER IN OUR
FORECAST AREA BEFORE INTERROGATING SEVERAL OF THE FORECAST
INGREDIENTS THAT WERE THE FOCUS THIS MORNING. CHALLENGES WERE
LOOKING AT PRECIP TYPE AND INTENSITY TODAY...TO SEE IF SOME PLACES
COULD GET SOME BRIEF ACCUMULATION NAMELY NEAR THE I-80 /FIRST SUCH
ACCUMULATION IN OVER 15 YEARS AND LONGER FOR SOME/...AND THEN
LOOKING AT LAKE EFFECT PRECIP POTENTIAL AND TYPE FOR MAINLY PORTER
COUNTY INDIANA LATE TONIGHT AND WEDNESDAY MORNING.
SYNOPSIS...VIGOROUS SHORT WAVE ENTERING WESTERN IA EARLY THIS
MORNING ON A 120+ JET IS BEGINNING TO CURL MORE SE AROUND THE BASE
OF THE LONG WAVE TROUGH RESPONSIBLE FOR OUR COLD LATE OCTOBER
SNAP. A SURFACE REFLECTION IS DEPICTED IN OBSERVATIONS WITH A
BROAD LOW ACROSS WESTERN IA WHICH WILL TIGHTEN AND DEEPEN THROUGH
THIS MORNING. SOME LIGHT RAIN IS SEEN ACROSS PARTS OF CENTRAL AND
WESTERN IA IN THE WARM AIR ADVECTION FLANK OF THIS CLIPPER.
MODEL PREFERENCE...MODEL GUIDANCE IS IN GOOD GENERAL AGREEMENT
OF THIS WAVE TRANSITIONING EAST SOUTHEAST THIS AFTERNOON ACROSS
CENTRAL IL WITH SOME VARIABILITY IN LATITUDE OF ITS KEY
FEATURES...WHICH OF COURSE DICTATE ALL THE KEY ELEMENTS SUCH AS
PLACEMENT OF HEAVIER PRECIP AND SUBTLE THERMAL DIFFERENCES THAT
INFLUENCE WHERE TRANSITION TO RA/SN MIGHT OCCUR. HAD LEANED A
LITTLE MORE TO THE 00Z NAM WHICH HAS VERY CLOSE SUPPORT BY THE 00Z
EC AND THE 03Z SREF MEAN. IT SHOULD BE NOTED THIS 00Z NAM HAD
SHIFTED SLIGHTLY FURTHER SOUTH THAN ITS PRECEDING 18Z RUN...AND
NOW THE 06Z SOLUTION HAS EVEN SHIFTED A BIT FURTHER SOUTH. THE
TREND FROM THAT OF TIGHTENING THE PRECIP GRADIENT ON THE NORTH
SIDE HAS ALSO BEEN NOTED WHICH MAKES GOOD SENSE WITH HOW THIS
SYSTEM IS ORIENTED AND ITS GENERALLY COMPACT NATURE AND QUICK
MOVEMENT. THE MAIN POINT WITH THIS IS IT BASICALLY KEEPS PRECIP
OUT OF CHICAGO. HAVE NOT GONE THAT SHARP BUT HAVE TIGHTENED THAT
NORTHERN GRADIENT.
TODAY AND TONIGHT...THE UPPER WARM AND MOIST ASCENT AHEAD OF THE
CLIPPER SHOULD LEAD TO A BLOSSOMING OF RADAR ECHOES ACROSS THE
WESTERN FORECAST AREA BY LATER THIS MORNING. GOOD CONVERGENCE AND
THERMAL GRADIENT TIGHTENING IN THE MID-LEVELS...WITH SUPPORTIVE
LAPSE RATES...WILL LIKELY CREATE SOME TEMPORARY MORE INTENSE WEST-
TO-EAST CORRIDORS. MOST HIGH RESOLUTION GUIDANCE BOTH LOCALLY AND
NATIONALLY TEND TO INDICATE THIS...ALTHOUGH AGAIN WITH
DISCREPANCIES IN HOW FAR NORTH...SOME AS FAR NORTH AS AROUND
I-88...OTHERS TOWARD PEORIA TO BLOOMINGTON/NORMAL. THIS HEAVIER
PRECIP IS IMPORTANT BECAUSE MARGINAL THERMAL PROFILES WOULD NEED
THE DIABATIC COOLING TO THE WET BULB /OR COOLER/ TO ENABLE SNOW TO
MIX IN TO THE SURFACE. HAVE GENERALLY FAVORED THE
LEE/LASALLE/LIVINGSTON COUNTIES THE MOST THIS AFTERNOON...AS THAT
CORRIDOR OF WET BULB COOLING AT THE SURFACE /TEMPS DROPPING INTO
THE MID 30S/ SHOULD BE SHIFTING SOUTHEAST THROUGH THOSE COUNTIES.
IF SNOW CAN MATERIALIZE...TEMPORARY RATES COULD CERTAINLY BE
ENOUGH TO BRING DOWN VISIBILITY QUICKLY...AND ITS POSSIBLE THOUGH
NOT REALLY FAVORED TO SEE SOME LIGHT SLUSHY ACCUMULATION. LATE IN
THE DAY AND THIS EVE THE PROFILES BECOME MORE SUPPORTIVE TO SEE A
MIX ACROSS THE WHOLE AREA...BUT THE OVERALL STRONGER FORCING IS
WEAKENING AS THE CLIPPER TRANSITIONS AWAY. SO REALLY NOT EXPECTING
ANY ACCUMULATION ELSEWHERE IF ANY OTHER PLACES CAN ACTUALLY CHANGE
OVER. IN MUCH OF THE CHICAGO METRO /OUTSIDE OF THE FAR SOUTHWEST
AND SOUTH/ THE PROFILES JUST APPEAR TOO WARM TO SUPPORT A LONG
CHANGEOVER IF ANY GIVEN MORNING MODERATION IN TEMPS.
LAKE EFFECT...IN THE WAKE OF THE CLIPPER AND ITS SURFACE LOW
REFLECTION MOVING INTO INDIANA...WINDS WILL TURN MORE NORTHERLY
AND DOWN THE FETCH OF THE LAKE. IT APPEARS THEIR IS A 6 TO 12 HOUR
WINDOW OF GOOD N-S CONVERGENCE INTO MAINLY NW IN. MODERATE TO
EXTREME LOW-LEVEL INSTABILITY WILL BE IN PLACE OVER THE LAKE
GIVEN 850MB TEMPERATURES OF -4C TO -6C. NAM PROFILES OVER THE LAKE
GIVEN MODIFIED PARCELS NEAR THE SURFACE LAKE TEMPERATURES SUPPORT
CLOUD DEPTHS OF 15K FT. ITS NOTED THIS MORNING THAT THE AIR
TEMPERATURE AT THE SOUTH BUOY IS ONLY 42 DESPITE A WATER
TEMPERATURE OF 60. SO THE INSTABILITY MAY NOT BE AS EXTREME AS SOME
MODIFIED GUIDANCE SHOWS...BUT STILL AMPLE FOR DECENT SHOWERS.
PRECIP TYPE IS A REAL CHALLENGE AND AGAIN BASED ON INTENSITY. IT
WOULD SEEM ALONG THE IMMEDIATE LAKE SHORE WITH ONSHORE FLOW IT
WOULD BE TOUGH TO GET EVEN A CHANGEOVER. INLAND THERE IS CERTAINLY
THAT CHANCE AND IF THE CONVERGENCE IS STRONG...THEN THAT
INSTABILITY WILL TRAIN INLAND POTENTIALLY CREATING A PROBLEM FOR
QUICK ACCUMULATION IF COLD ENOUGH WITH HEAVY SUSTAINED RATES.
HAVE ADDED UNDER AN INCH OF ACCUMULATION IN EASTERN PORTER
COUNTY...BUT CERTAINLY THE CHANCE IS THERE FOR MORE. FOR NOW
THOUGH...THERMAL PROFILES ARE AWFULLY MARGINAL AND WITH THE CAVEAT
OF ONSHORE FLOW POTENTIALLY LEADING TO RAIN SHOWERS FOR MUCH OF
THAT TIME.
BEYOND...MORE TRANQUIL CONDITIONS PREVAIL HOWEVER STILL UNDER
NORTHWEST FLOW ALOFT...SO BELOW NORMAL TEMPERATURES CONTINUE. THE
BACK SIDE OF THE TROUGH SHIFTS EAST AS DOES ITS JET...SO THE PATH
FOR SHORT WAVES WILL BE MORE TO THE NORTH AND EAST BY
THURSDAY...MEANING LESS OF A CHANCE FOR PRECIP. LAKE EFFECT
ORIENTATION LOOKS TO BE EAST OF OUR INDIANA COUNTIES ON MOST OF
THESE DAYS.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RAIN MIXING WITH AND CHANGING OVER TO WET SNOW THIS AFTERNOON
AFTER 19 UTC.
* VIS TO DROP AS LOW AS 1-2 MILES AND CIGS AROUND 1,000 FT FOR A
PERIOD. BETTER CHANCES WILL BE AT MDW.
KJB
//DISCUSSION...UPDATED 18Z...
THE MAIN FORECAST CONCERNS THIS AFTERNOON IS THE SNOW THAT WILL BE
AFFECTING THE EASTERN TERMINALS THROUGH THE AFTERNOON. ALTHOUGH THE
SNOW SHOULD NOT RESULT IN ACCUMULATIONS ON RUNWAYS...IT COULD REDUCE
THE VISIBILITIES DOWN TO 1 TO 2 MILES FOR A PERIOD THIS
AFTERNOON...ALONG WITH CIGS AROUND 1,000 FEET...ESPECIALLY AT KMDW
AND KGYY.
IT STILL APPEARS THE HEAVIEST PRECIP WILL BE FAVORED SOUTH WITH THIS
SYSTEM. HOWEVER...THERE IS A BAND OF LIGHTER PRECIP MOVING ACROSS
NORTHERN ILLINOIS AND THIS WILL LIKELY AFFECT ALL THE TERMINALS TO
SOME POINT THIS AFTERNOON. I WENT WITH LOWER VIS AND CIGS AT KMDW
AND KGYY AS THEY STAND THE BEST CHANCES FOR SOME SLIGHTLY HEAVIER
PRECIP. IT COULD BEGIN AS SOME LIGHT RAIN INITIAL...BUT AS
EVAPORATION COOLING TAKES OVER IT SHOULD MIX WITH AND CHANCE OVER
THE SNOW. WITH SNOW LIKELY BECOMING THE MAIN PRECIP TYPE...THIS
SHOULD LEAD TO LOWER VISIBILITIES THAN PREVIOUSLY FORECAST.
WIND DIRECTIONS WILL BE A CHALLENGE THIS AFTERNOON...WITH THE LOW
MOVING TO THE SOUTH. IT APPEARS THEY WILL BE OUT OF THE SOUTHWEST
THROUGH THE AFTERNOON...THEN SHIFTING MORE NORTHWEST TONIGHT. WIND
SPEEDS SHOULD REMAIN AT OR LESS THEN 10KT.
CONDITIONS SHOULD IMPROVE THIS EVENING AS THE SYSTEM SHIFTS EAST OF
THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN PRECIP AFFECTING THE TERMINALS WITH RAIN/SNOW
* MEDIUM CONFIDENCE IN PERIOD OF 1 TO 2 SM VIS RANGE THIS
AFTERNOON IN -SN...ESPECIALLY AT KMDW.
* LOW TO MEDIUM CONFIDENCE IN LOW MVFR CIGS AROUND 1,000 FT
THROUGH THE AFTERNOON...WITH IFR POSSIBLE.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH FRIDAY...VFR.
SATURDAY...MVFR POSSIBLE LATE.
SUNDAY...VFR.
MONDAY...CHANCE OF RAIN.
JEE
&&
.MARINE...
237 PM CDT
FAIRLY STEADY STATE CONDITIONS EXPECTED THROUGH THE REMAINDER OF THE
WEEK. LOW PRESSURE WILL CONTINUE TO SPIN AND GRADUALLY SHIFT EAST
OVER EASTERN CANADA WHILE HIGH PRESSURE BUILDS SOUTHEAST FROM THE
NORTHERN PLAINS TODAY TO THE LOWER TO MID MISSISSIPPI VALLEY BY
FRIDAY. THE PERSISTENT MODERATE NORTHWESTERLY GRADIENT THROUGH THE
PERIOD WILL RESULT IN NORTHWEST WINDS OF 15 TO 25 KT OVER MOST OF
THE LAKE THROUGH FRIDAY...WITH SOME MINOR UNDULATIONS AS WEAK
PERTURBATIONS MOVE THROUGH THE REGION. WITH TEMPORARY WEAKER WINDS
TODAY OVER THE SOUTHERN PORTIONS OF THE LAKE...WILL ALLOW THE SMALL
CRAFT ADVISORY TO EXPIRE FOR THIS AFTERNOON...BUT NORTHERLY WINDS
PICKING UP AGAIN OVERNIGHT WILL ALLOW WAVES TO ONCE AGAIN
GROW...THUS WILL HOIST A NEW SMALL CRAFT ADVISORY GOING INTO EFFECT
EARLY WEDNESDAY MORNING. LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE
CANADIAN PRAIRIES AND OVER LAKE SUPERIOR EARLY SATURDAY WITH WINDS
AT LEAST BRIEFLY RETURNING TO SOUTHWEST FRIDAY NIGHT THROUGH LATE
MORNING SATURDAY. A FRONT SWEEPING ACROSS THE LAKE SATURDAY
AFTERNOON WILL THEN TURN WINDS BACK TO THE NORTHWEST THROUGH THE
REMAINDER OF THE WEEKEND. TRANSIENT HIGH PRESSURE QUICKLY MOVES
ACROSS THE LAKE MONDAY ALLOWING WINDS TO DIMINISH...BEFORE TURNING
SOUTHEASTERLY AGAIN AHEAD OF A BROAD AREA OF LOW PRESSURE DEVELOPING
OVER THE PLAINS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...5 AM WEDNESDAY
TO 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...5 AM WEDNESDAY TO
10 PM WEDNESDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
222 PM CDT Tue Oct 22 2013
.DISCUSSION...
ISSUED 210 PM CDT Tue Oct 22 2013
Latest surface analysis has low pressure just north of Quincy with
a warm front extending from the low over extreme southwest Illinois.
A large area of rain extended mainly north and east of the surface
low with a narrow band of snow falling just north of our forecast
area to the Quad Cities where a couple of inches of wet snow
accumulated thru the morning hours. We did receive a report of some
snow in Altona in northern Knox county this morning but temperatures
were well into the 30s at that time.
The main forecast concern in the short term will be overnight low
temps the next several nights with the potential for widespread
freezing temperatures by tomorrow morning, and especially late Thu
night into Friday morning when surface high pressure will be
approaching our area. In the longer range...our cold pattern will
begin to break down as the deep vortext north of the Great Lakes
shifts off the north and east of the region by late in the weekend
and into early next week with our 500 mb flow turning more southwesterly
increasing not only our temperatures but also our rain chances.
SHORT TERM...Tonight through Friday
Surface low forecast by models to track east-southeast to near
Mattoon by early this evening, and then finally east of our forecast
area by midnight. With the track a bit further north than previous
forecasts had indicated, the low levels look to stay too warm to
support any snow before we lose the ice crystals in the upper portions
of the cloud. The better 700-500 mb QG forcing shifts off to our east
rather quickly early this evening with quite a bit of wrap around
moisture/clouds in the wake of the system. Forecast soundings and
time-height cross sections indicate some clearing taking place by
midnight over our northwest and then working east and south later
tonight. The NAM-WRF 850 temps showing some decent cold air advection
overnight as the surface wave shifts into Kentucky by Wednesday morning.
With the clear sky and diminishing winds overnight, it appears the setup
would support more widespread freezing temperatures than what was
experienced last night so went ahead and issued a Freeze Warning for
areas north of I-70. Morning lows will range from roughly 25 to 30
degrees over a larger area and for a longer duration than last night.
Cloud cover will be slower to clear out along and south of I-70 so
will hold off any headlines in that area tonight as lows dip into
the lower to middle 30s. Next fast moving clipper will track southeast
into the region by late Wednesday morning into the afternoon hours
with an increase in clouds during the day. However, the moisture and
lift associated with this upper wave is not nearly as strong as today`s
forcing, as a result, will continue with only slight chance pops during
the late morning thru the early evening hours. As far as overnight
temps late Wed night into Thursday morning, forecast soundings continue
to indicate quite a bit of low level moisture in the wake of the clipper
system on Wednesday, so guid temps not as cold as tonight across the
southeast with lows in the low to mid 30s once again. It appears the
better chance for widespread freezing temperatures in the southeast
would be on Friday morning as another cold high pressure area approaches
from the west. Morning lows will drop to between 27 and 30 degrees in
areas along and south of I-70, as a result, a Freeze Watch has been
issued for the far southeast for the early morning hours of Friday.
After a cold start on Friday, high pressure will keep the weather
cool and dry across the entire area as we head into the weekend.
LONG TERM...Saturday through Tuesday
Medium range models continue to suggest a major pattern change to
take place early next week as the deep vortex north of the Great
Lakes shifts off to our east and north. 500 mb heights will be on
the rise across our area in response to a trof that is forecast to
develop to our west and close off a low in the Rockies by late
Tuesday and track SSE into the southern Plains. This will bring in
much warmer air to the region with afternoon temperatures approaching
60 on Monday and well into the 60s by Tuesday. Shower chances will
begin to increase, especially Monday night through Tuesday as a
series of shortwaves are forecast to eject from the trof to our
southwest and track northeast into forecast area.
Smith
&&
.AVIATION...
ISSUED 1237 PM CDT Tue Oct 22 2013
Main aviation forecast challenges will be timing of potential IFR
ceilings into the area later this afternoon and evening...and
timing the clearing trend later tonight.
Low pressure currently over southeast Iowa will track E/SE across
central Illinois this afternoon...accompanied by a band of light
rain. Once the low passes, winds will swing around to the N/NE and
should pull IFR ceilings currently in place across much of Iowa
and northwest Illinois into the area. Model guidance is in
disagreement, with the GFS and NAM indicating MVFR or even VFR
ceilings persisting. Given latest satellite trends, prefer the
more pessimistic HRRR which brings the lower ceilings into central
Illinois behind the departing low. Based on HRRR timing, have
introduced IFR ceiling at KPIA by 21z, then further east to KCMI
by 02z. Clouds will be rather slow to clear tonight, with the HRRR
hanging on to IFR conditions until around midnight. Skies should
scatter at KPIA by 05z, then eastward to KCMI by around 10z.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH from late Thursday night through Friday morning FOR
ILZ062-063-066>068-071>073.
FREEZE WARNING from 1 AM to 8 AM CDT Wednesday FOR ILZ027>031-
036>038-040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1220 PM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 1215 PM CDT TUE OCT 22 2013
DESPITE WEAK FORCING...PRECIPITATION HAS LINGERED ACROSS MUCH OF
CWA THROUGH THE MORNING. THIS WILL CONTINUE TO PUSH SLOWLY
SOUTHEAST THROUGH THE REMAINDER OF THE AFTERNOON. HAVE THEREFORE
INCREASED POPS THROUGH THE AFTERNOON. IN ADDITION...WITH COLDER
AIR WORKING IN BEHIND SYSTEM PRECIPITATION HAS CHANGED TO SNOW
ACROSS MUCH OF CENTRAL IOWA...AND HAVE INTRODUCED POSSIBLE
ACCUMULATIONS NEAR 0.1 OF AN INCH A FEW COUNTIES FURTHER SOUTH.
&&
.SHORT TERM /TODAY/...
ISSUED AT 341 AM CDT TUE OCT 22 2013
MAIN CONCERN TODAY WILL OBVIOUSLY BE EVOLUTION OF CURRENT SYSTEM
PASSING THROUGH THE MO VALLEY. DAKOTAS SHORT WAVE/PV ANOMALY
CONTINUES TO STRENGTHEN AS IT APPROACHES WRN IA. ASSOCIATED PRECIP
IS CURRENTLY SOMEWHAT PATCHY...LIKELY DUE TO FAIRLY LOW STATIC
STABILITIES...BUT IS EXPECTED TO ORGANIZE SOMEWHAT MORE LATER THIS
MORNING. FORCING IS DEEP...DRIVEN KINEMATICALLY BY DPVA AND
DIVERGENCE IS LEFT EXIT REGION OF SASKATCHEWAN INTO HIGH PLAINS
JET SEGMENT. THERMODYNAMIC FORCING IS CENTERED INTO IA AND
CURRENTLY NOT THAT STRONG HOWEVER BUT MODELS DO STRENGTHEN THE
THETA-E ADVECTION AND FRONTOGENETICAL FORCING INTO THE MORNING.
THIS COUPLED FORCING WILL RESULT IN INCREASED DENDRITIC GROWTH ZONE
/DGZ/ UPWARD MOTION. MODEL DEPICTIONS OF THIS...LOOKING AT
290-300K ISENT LAYER...ARE SOMEWHAT PROBLEMATIC HOWEVER AND
AFOREMENTIONED LOW STATIC STABILITIES HAVE RESULTED IN COMPACT
MODEL BULLSEYES OF LIFT WHICH ARE DIFFICULT TO EASILY TRANSLATE
INTO HIGHER SNOW RATIOS AND RESULTANT SENSIBLE WEATHER. AREAS OF
HIGHER SNOW RATES MAY END UP BEING NEAR CONVECTIVE AND SOMEWHAT
ISOLATED. TO LOWER CONFIDENCE EVEN FURTHER...LOWEST 500M TEMPS
HOVER RIGHT AROUND CRITICAL RAIN/SNOW VALUES WHICH ARE CO-LOCATED
WITH THE DGZ LIFT. THIS MAKES RAIN/SNOW LINE UNCERTAIN AND WHETHER
THE DGZ OMEGA WILL BE REALIZED IN RAIN OR SNOW. TAKING A BLEND OF
THE HIGHER RES RAP AND NAM WOULD SUGGEST THE BEST LOCATION FOR
ACCUMULATING SNOWS WOULD BE SIMILAR TO PREVIOUS TRACK FROM NW IA
SEWD TO NEAR WATERLOO AND MARSHALLTOWN. STILL HAVE ACCUMS OF AN
INCH OR LESS...WITH A POCKET OF HIGHER AMOUNTS NEAR AN IOWA
FALLS/MARSHALLTOWN/WATERLOO TRIANGLE WHERE SNOW MAY BRIEFLY
INTENSIFY AROUND 12Z OR 15Z. CONFIDENCE IN SNOW AMOUNTS IS QUITE
LOW HOWEVER DUE TO CONCERNS ABOVE AND MELTING ISSUES WITH ROAD
SURFACE TEMPS STILL 35F OR HIGHER AND THE GROUND WARM AS WELL.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 341 AM CDT TUE OCT 22 2013
MAIN FORECAST CONCERN IS WITH WEAK SHORTWAVE TO BRING ADDITIONAL
PRECIP CHANCES ON WEDNESDAY AND THEN CONTINUED COLD TEMPERATURES
THROUGH THE END OF THE WORK WEEK AND INTO THE WEEKEND.
TONIGHT THROUGH WEDNESDAY...THE 22.00Z MODELS RUNS IN DECENT
AGREEMENT WITH BRINGING WEAK VORT MAX FURTHER SOUTH AND CAUSED
FOR A SHIFT IN POPS SOUTHWEST LEAVING THE NORTHEAST PORTIONS OF
THE FORECAST AREA DRY TOMORROW. THERE IS A SMALL WINDOW FOR SNOW
POTENTIAL DURING THE MORNING...ROUGHLY BETWEEN 12-15Z WEDNESDAY
WHEN THE COLUMN BECOMES SATURATED AND REMAINS BELOW
FREEZING AND ENOUGH FORCING IN THE SNOW GROWTH ZONE TO GENERATE
SNOW. THIS WILL BE MAINLY OVER WEST CENTRAL TO NORTHWEST IOWA.
HOWEVER...LOW CONFIDENCE WITH MUCH...IF ANY SNOW ACCUMULATION AS
SURFACE TEMPERATURES LOOK TO QUICKLY RISE ABOVE FREEZING AND
FORCING QUICKLY MOVES SOUTH. AS A RESULT...DECREASED SNOW AMOUNTS
TO LESS THAN HALF AN INCH. THETA-E ADVECTION AND ISENTROPIC LIFT
WILL QUICKLY MOVES FROM NORTHWEST IOWA TO SOUTHEAST IOWA DURING
THE DAY WEDNESDAY. NAM/GFS HAVE DECENT FRONTOGENETICAL FORCING
BETWEEN 750-600MB BY 12Z IN NORTHWEST IOWA AND THEN TRANSITION THE
FORCING INTO SOUTH-CENTRAL TO SOUTHEAST PORTIONS OF THE FORECAST
AREA BY 18Z. WITH THE QUICKER MOVEMENT OF THE SYSTEM...DECREASED
POPS OVER THE WEST AND NORTH PAST 21Z.
THURSDAY THROUGH MONDAY....LARGE SURFACE HIGH BUILDS INTO THE
REGION UNDERNEATH NORTHWEST FLOW ALOFT THROUGH SATURDAY BEFORE
THE GFS/ECMWF BRING A DRY COLD FRONT ACROSS THE STATE SOMETIME
SATURDAY. NEXT LONGWAVE TROUGH BEGINS TO DIG INTO THE WESTERN U.S.
BY EARLY NEXT WEEK PLACING AN INVERTED SURFACE TROUGH OVER IOWA BY
MONDAY. THIS WILL BE THE NEXT BEST CHANCE OF PRECIP TO THE
FORECAST AREA.
&&
.AVIATION...22/18Z
ISSUED AT 1215 PM CDT TUE OCT 22 2013
LIGHT PRECIPITATION WILL LINGER WITH MVFR CEILING AND VISIBILITIES
AT SITES...WITH EXCEPTION OF KMCW WHICH WILL REMAIN NORTH AND IN
VFR CONDITIONS. BEHIND PRECIPITATION CEILINGS WILL SLOWLY LIFT BACK
TO VFR CEILINGS...GENERALLY NEAR 00Z AT SITES. WINDS WILL SHIFT TO
THE WEST THROUGH THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...AWB
SHORT TERM...SMALL
LONG TERM...PODRAZIK
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS WICHITA KS
1154 AM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 712 AM CDT TUE OCT 22 2013
THIS MORNING:
THE PURPOSE FOR THE UPDATE IS TWO-FOLD:
1) TO REMOVE SPRINKLES FROM PARTS OF CENTRAL & SOUTH-CENTRAL KS.
2) TO ADJUST CLOUD COVER TO REFLECT SATELLITE TRENDS TO FOCUS
CLOUD COVER OVER SE KS THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
TODAY:
ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE
OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING
ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING.
OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT
RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND
POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS
AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE
FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES
WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY.
TONIGHT:
RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES
EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS
WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR
WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL
LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST
ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF
NEEDED.
WED-THU:
QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD
OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY.
TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN
HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS.
TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT
WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE
TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION
CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF
MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE OCT 22 2013
MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE
TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN
FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW
DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN
TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON
ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE
BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON
MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST
OF THE DAY. -HOWERTON
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1150 AM CDT TUE OCT 22 2013
NORTHWESTERLY WINDS WILL GUST TO 24-30 KT THIS AFTERNOON...BEFORE
DIMINISHING AND BECOMING LIGHT NORTHEASTERLY THIS EVENING. WINDS
WILL THEN BECOME SOUTH-SOUTHWESTERLY BY LATE WEDNESDAY MORNING.
SOME MID-LEVEL ALTOCUMULUS MAY AFFECT ESPECIALLY NORTHEASTERN KS
TONIGHT IN THE NORTHWEST FLOW ALOFT.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 70 39 71 38 / 0 0 0 0
HUTCHINSON 70 38 69 37 / 0 0 0 0
NEWTON 69 38 69 36 / 0 0 0 0
ELDORADO 69 35 69 36 / 10 0 0 0
WINFIELD-KWLD 71 37 73 38 / 0 0 0 0
RUSSELL 67 37 67 34 / 0 0 0 0
GREAT BEND 68 37 68 34 / 0 0 0 0
SALINA 67 36 69 36 / 0 0 0 0
MCPHERSON 69 37 69 36 / 0 0 0 0
COFFEYVILLE 69 36 69 38 / 10 0 0 0
CHANUTE 67 33 65 35 / 10 0 10 0
IOLA 65 32 65 35 / 10 0 10 0
PARSONS-KPPF 67 33 67 34 / 10 0 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053-
069>072-094>096-099-100.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
610 PM EDT TUE OCT 22 2013
.SYNOPSIS...
A COLD FRONT WILL PUSH EAST OF THE AREA TONIGHT THEN A SMALL AREA
OF LOW PRESSURE WILL SLIDE SOUTH OF THE REGION ON WEDNESDAY. A
LARGE TROUGH OF LOW PRESSURE WILL BUILD INTO THE EAST THURSDAY
INTO FRIDAY AS CHILLY AIR PUSHES DOWN FROM CANADA.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
610 PM UPDATE...LOW PRES JUST EAST OF JAMES BAY WILL REMAIN
QUASI-STATIONARY TONIGHT AND CONTINUE TO DEEPEN TO AROUND 985 MB
BY 12Z WED. A PRE-FRONTAL TROUGH STRETCHES FROM ERN AROOSTOOK
COUNTY TO NEAR BANGOR AT 22Z. THERE IS A LINE OF SHOWERS
ASSOCIATED WITH THIS TROUGH. THERE IS A SECOND LINE OF SHOWERS
WHICH ARE ASSOCIATED WITH A STRONG COLD THAT EXTENDS FROM AROUND
FT KENT TO GREENVILLE. THIS FRONT WILL SWEEP ACROSS THE REMAINDER
OF THE CWA THIS EVENING LIKELY MERGING WITH THE PRE-FRONTAL
TROUGH. THE LAST OF THE SHOWERS SHOULD EXIT SOUTHEAST WASHINGTON
COUNTY BY AROUND MIDNIGHT. IN THE WAKE OF THE FRONT A MUCH COLDER
AIR MASS WILL SPREAD ACROSS THE REGION OVERNIGHT. MADE SOME TWEAKS
TO POP/WX GRIDS BASED ON THE LATEST RADAR RETURNS. ALSO REMOVED
THE MENTION OF THUNDER FOR THIS EVENING AS THERE HAVE NOT BEEN ANY
CLOUD TO GROUND STRIKES NOR ANY IN CLOUD LIGHTNING.
PREVIOUS DISCUSSION...
AREA OF SHOWERS SETTING UP AHEAD OF THE APCHG COLD
FRONT PER THE 18Z RADAR TREND. 18Z SFC ANALYSIS SHOWS A PRE-
FRONTAL TROF OUR AHEAD OF THE COLD FRONT W/THE SHOWERS ALIGNED
W/THE BOUNDARY. THE LATEST HRRR WAS DOING QUITE WELL W/THE
PLACEMENT AND MOVEMENT OF THE PRECIP SHIELD. LAPS SOUNDINGS SHOWED
SOME DESTABILIZATION MAINLY ACROSS THE CENTRAL HIGHLANDS AND
INTERIOR DOWNEAST WHERE SOME HEATING AND THE BEST 0-6KM SHEAR
EXISTS. CONTINUED TO CARRY ISOLD TSTMS IN THESE AREAS THROUGH 00Z.
OTRW, SHOWERS AND GUSTY WINDS OF UP TO 35 MPH AREA POSSIBLE.
LATEST RADAR VELOCITY DID SHOW 40 KTS AT 6K FT ACROSS THE CENTRAL
HIGHLANDS AT 18Z. TEMPERATURES ARE PEAKED AND NOW WILL BEGIN TO
FALL BACK AFTER 00Z WHEN THE COLD FRONT ARRIVES. SHOWERS WILL BE
INTO NEW BRUNSWICK BY 02Z OR SO AND THEN PARTIAL CLEARING WILL
BEGIN LATER THIS EVENING INTO THE OVERNIGHT HOURS. CAA WILL BRING
BREEZY CONDITIONS FOR A WHILE UP THROUGH 06Z AND THEN WINDS WILL
DROP OFF AS THE GRADIENT LOOSENS. COLD AIR TO ARRIVE BY WEDNESDAY
MORNING W/READINGS BY 7 AM IN THE UPPER 20S TO AROUND 30 ACROSS
THE NORTH AND WEST AND LOW/MID 30S INTERIOR DOWNEAST AND THE
COAST. COLLABORATED W/NERFC AND LOWERED QPF AMOUNTS TO 0.15-0.30
ACROSS THE NORTHERN 1/2 OF THE CWA W/0.10 OR LESS FOR THE CENTRAL
HIGHLANDS AND INTERIOR DOWNEAST.
A CHILLY DAY ON WEDNESDAY W/SOME BRIEF RIDGING AND SUNSHINE. IT
WILL FEEL SOMEWHAT LIKE A SHOCK TO THE SYSTEM AS DAYTIME HIGHS ARE
EXPECTED TO BE IN THE UPPER 40S TO AROUND 50 NORTH AND WEST TO
LOWER 50S DOWNEAST. DECIDED ON THE ECMWFMOS/GMOS BLEND FOR
TEMPERATURES.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
A DEEP TROUGH MOVING INTO THE EAST WILL USHER IN SOME VERY CHILLY
AIR FOR THE LATTER PART OF THIS WEEK. A SMALL WAVE OF LOW PRESSURE
TRACKING OFF THE MID ATLANTIC COAST AND SLIDING WELL SOUTH OF THE
REGION MAY BRING SOME LIGHT RAIN TO DOWNEAST LOCATIONS EARLY
WEDNESDAY EVENING. OTHERWISE, WEDNESDAY NIGHT WILL BE PARTLY CLOUDY
AND BECOMING BREEZY AS THE GRADIENT SOUTH OF A LARGE LOW PRESSURE
SYSTEM MOVING INTO EASTERN CANADA BEGINS TO EFFECT THE REGION. THIS
WILL GIVE WAY TO A WINDY AND CHILLY DAY ON THURSDAY AS COLD AIR
PULLING AROUND THE LOW FLOWS INTO THE STATE. SKIES WILL RANGE FROM
PARTLY CLOUDY DOWNEAST TO OVERCAST IN STRATOCUMULUS CLOUDS ACROSS
THE NORTH AND SOME LIGHT RAIN, OR POSSIBLY SNOW SHOWERS, MAY AFFECT
NORTHERN AREAS ESPECIALLY OVER HIGHER ELEVATIONS. BREEZY AND CHILLY
CONDITIONS WITH A MOSTLY CLOUDY SKY NORTH AND PARTIAL CLOUDINESS
DOWNEAST WILL CONTINUE THURSDAY NIGHT INTO FRIDAY. SOME PATCHY LIGHT
SHOWERS OR FLURRIES ARE POSSIBLE IN THE HIGHER ELEVATIONS IN THE
WEST THURSDAY NIGHT OR FRIDAY. OTHERWISE, MAINLY DRY WEATHER WILL
CONTINUE OVER THE AREA INTO FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A SHORTWAVE CASCADING INTO THE TROUGH FRIDAY NIGHT WILL DEVELOP LOW
PRESSURE IN THE GREAT LAKES ON SATURDAY. CHILLY AIR WILL BE IN PLACE
SATURDAY INTO SATURDAY EVENING AS THIS LOW APPROACHES WITH
INCREASING CLOUDS. PRECIPITATION WILL SPREAD ACROSS THE REGION
SATURDAY EVENING. CURRENT GUIDANCE INCLUDING THE GFS AND ECMWF ARE
INDICATING THE AIR WILL LIKELY BE COLD ENOUGH TO SUPPORT SOME WET
SNOW ACROSS THE NORTH AS THE PRECIPITATION MOVES IN SATURDAY EVENING.
THE ECMWF HAS LOW LEVEL CRITICAL THICKNESSES BELOW 1300 AT 1000-850
MB, COLD ENOUGH TO SUPPORT SNOW, ACROSS THE NORTHERN HALF OT THE
STATE SATURDAY EVENING. THE GFS HAS THE NORTHERN THIRD OF THE STATE
COLD ENOUGH FOR SNOW. ALL OF THE GFS ENSEMBLE MEMBERS SUPPORT
THICKNESSES COLD ENOUGH FOR SNOW OVER THE NORTH. THE CANADIAN MODEL,
HOWEVER, INDICATES THICKNESSES WILL BE TOO WARM FOR SNOW. THE AIR IS
EXPECTED TO WARM A BIT LATE SATURDAY NIGHT INTO SUNDAY MORNING AS
THE LOW CENTER TRACKS ACROSS THE NORTHERN PART OF THE STATE SO ANY
SNOW WOULD LIKELY TURN OVER TO RAIN. AN INCH OR TWO OF SNOW MAY FALL
ACROSS THE NORTHERN PART OF THE STATE BEFORE THE CHANGE OVER WITH
THE GREATEST CHANCES FOR SOME ACCUMULATION OVER ELEVATIONS ABOVE 700
FT. PRECIPITATION WILL END SUNDAY MORNING. ANOTHER SURGE OF CHILLY
AIR WILL FOLLOW THE SYSTEM EARLY NEXT WEEK AS HIGH PRESSURE BUILDS
IN FROM CANADA.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA
AND THEN VFR RIGHT INTO WEDNESDAY.
SHORT TERM: CONDITIONS ARE EXPECTED TO IMPROVE TO VFR WEDNESDAY
NIGHT THEN BE VFR ON THURSDAY. CONDITIONS MAY LOWER TO MVFR IN
STRATOCUMULUS CLOUDS ACROSS THE NORTH LATE THURSDAY INTO THURSDAY
NIGHT AND REMAIN VFR DOWNEAST. VFR CONDITIONS ARE EXPECTED FRIDAY
INTO SATURDAY. CONDITIONS WILL THEN LOWER TO IFR IN PRECIPITATION
SATURDAY NIGHT.
&&
.MARINE...
NEAR TERM: SEAS HAVE CONTINUED TO BUILD THIS AFTERNOON AND ARE NOW
RUNNING AROUND 5 FT AT THE EASTERN MAINE SHELF AS OF 5 PM EDT. THE
SCA TO STAY UP THROUGH MIDNIGHT. EXPECTING GUSTS TO 25KT THROUGH
MIDNIGHT AND THEN GRADIENT IS EXPECTED TO WEAKEN AS THE COLD FRONT
PASSES THROUGH THE WATERS. SW WINDS EXPECTED TO SHIFT TO THE WNW
LATER TONIGHT INTO WEDNESDAY. WINDS WILL DROP OFF TO 10 KT BY 12Z
WEDNESDAY W/SEAS DROPPING OFF TO LESS THAN 3 FT.
SHORT TERM: A STRONG SCA OR POSSIBLY A GALE WILL BE NEEDED FOR
GUSTY WEST WINDS ON THURSDAY. AN SCA WILL LIKELY BE NEEDED
THURSDAY NIGHT. WINDS SHOULD THEN BE BELOW SCA FRIDAY AND
SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...CB/HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...CB/HEWITT/BLOOMER
MARINE...CB/HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
336 PM EDT TUE OCT 22 2013
.SYNOPSIS...
A COLD FRONT WILL PUSH EAST OF THE AREA TONIGHT THEN A SMALL AREA
OF LOW PRESSURE WILL SLIDE SOUTH OF THE REGION ON WEDNESDAY. A
LARGE TROUGH OF LOW PRESSURE WILL BUILD INTO THE EAST THURSDAY
INTO FRIDAY AS CHILLY AIR PUSHES DOWN FROM CANADA.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AREA OF SHOWERS SETTING UP AHEAD OF THE APCHG COLD FRONT PER THE
18Z RADAR TREND. 18Z SFC ANALYSIS SHOWS A PRE-FRONTAL TROF OUR
AHEAD OF THE COLD FRONT W/THE SHOWERS ALIGNED W/THE BOUNDARY. THE
LATEST HRRR WAS DOING QUITE WELL W/THE PLACEMENT AND MOVEMENT OF
THE PRECIP SHIELD. LAPS SOUNDINGS SHOWED SOME DESTABILIZATION
MAINLY ACROSS THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST WHERE
SOME HEATING AND THE BEST 0-6KM SHEAR EXISTS. CONTINUED TO CARRY
ISOLD TSTMS IN THESE AREAS THROUGH 00Z. OTRW, SHOWERS AND GUSTY
WINDS OF UP TO 35 MPH AREA POSSIBLE. LATEST RADAR VELOCITY DID
SHOW 40 KTS AT 6K FT ACROSS THE CENTRAL HIGHLANDS AT 18Z. TEMPERATURES
ARE PEAKED AND NOW WILL BEGIN TO FALL BACK AFTER 00Z WHEN THE COLD
FRONT ARRIVES. SHOWERS WILL BE INTO NEW BRUNSWICK BY 02Z OR SO AND
THEN PARTIAL CLEARING WILL BEGIN LATER THIS EVENING INTO THE OVERNIGHT
HOURS. CAA WILL BRING BREEZY CONDITIONS FOR A WHILE UP THROUGH 06Z
AND THEN WINDS WILL DROP OFF AS THE GRADIENT LOOSENS. COLD AIR TO
ARRIVE BY WEDNESDAY MORNING W/READINGS BY 7 AM IN THE UPPER 20S TO
AROUND 30 ACROSS THE NORTH AND WEST AND LOW/MID 30S INTERIOR
DOWNEAST AND THE COAST. COLLABORATED W/NERFC AND LOWERED QPF
AMOUNTS TO 0.15-0.30 ACROSS THE NORTHERN 1/2 OF THE CWA W/0.10 OR
LESS FOR THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST.
A CHILLY DAY ON WEDNESDAY W/SOME BRIEF RIDGING AND SUNSHINE. IT
WILL FEEL SOMEWHAT LIKE A SHOCK TO THE SYSTEM AS DAYTIME HIGHS ARE
EXPECTED TO BE IN THE UPPER 40S TO AROUND 50 NORTH AND WEST TO
LOWER 50S DOWNEAST. DECIDED ON THE ECMWFMOS/GMOS BLEND FOR
TEMPERATURES.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
A DEEP TROUGH MOVING INTO THE EAST WILL USHER IN SOME VERY CHILLY
AIR FOR THE LATTER PART OF THIS WEEK. A SMALL WAVE OF LOW PRESSURE
TRACKING OFF THE MID ATLANTIC COAST AND SLIDING WELL SOUTH OF THE
REGION MAY BRING SOME LIGHT RAIN TO DOWNEAST LOCATIONS EARLY
WEDNESDAY EVENING. OTHERWISE, WEDNESDAY NIGHT WILL BE PARTLY CLOUDY
AND BECOMING BREEZY AS THE GRADIENT SOUTH OF A LARGE LOW PRESSURE
SYSTEM MOVING INTO EASTERN CANADA BEGINS TO EFFECT THE REGION. THIS
WILL GIVE WAY TO A WINDY AND CHILLY DAY ON THURSDAY AS COLD AIR
PULLING AROUND THE LOW FLOWS INTO THE STATE. SKIES WILL RANGE FROM
PARTLY CLOUDY DOWNEAST TO OVERCAST IN STRATOCUMULUS CLOUDS ACROSS
THE NORTH AND SOME LIGHT RAIN, OR POSSIBLY SNOW SHOWERS, MAY AFFECT
NORTHERN AREAS ESPECIALLY OVER HIGHER ELEVATIONS. BREEZY AND CHILLY
CONDITIONS WITH A MOSTLY CLOUDY SKY NORTH AND PARTIAL CLOUDINESS
DOWNEAST WILL CONTINUE THURSDAY NIGHT INTO FRIDAY. SOME PATCHY LIGHT
SHOWERS OR FLURRIES ARE POSSIBLE IN THE HIGHER ELEVATIONS IN THE
WEST THURSDAY NIGHT OR FRIDAY. OTHERWISE, MAINLY DRY WEATHER WILL
CONTINUE OVER THE AREA INTO FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A SHORTWAVE CASCADING INTO THE TROUGH FRIDAY NIGHT WILL DEVELOP LOW
PRESSURE IN THE GREAT LAKES ON SATURDAY. CHILLY AIR WILL BE IN PLACE
SATURDAY INTO SATURDAY EVENING AS THIS LOW APPROACHES WITH
INCREASING CLOUDS. PRECIPITATION WILL SPREAD ACROSS THE REGION
SATURDAY EVENING. CURRENT GUIDANCE INCLUDING THE GFS AND ECMWF ARE
INDICATING THE AIR WILL LIKELY BE COLD ENOUGH TO SUPPORT SOME WET
SNOW ACROSS THE NORTH AS THE PRICIPIATION MOVES IN SATURDAY EVENING.
THE ECMWF HAS LOW LEVEL CRITICAL THICKNESSES BELOW 1300 AT 1000-850
MB, COLD ENOUGH TO SUPPORT SNOW, ACROSS THE NORTHERN HALF OT THE
STATE SATURDAY EVENING. THE GFS HAS THE NORTHERN THIRD OF THE STATE
COLD ENOUGH FOR SNOW. ALL OF THE GFS ENSEMBLE MEMBERS SUPPORT
THICKNESSES COLD ENOUGH FOR SNOW OVER THE NORTH. THE CANADIAN MODEL,
HOWEVER, INDICATES THICKNESSES WILL BE TOO WARM FOR SNOW. THE AIR IS
EXPECTED TO WARM A BIT LATE SATURDAY NIGHT INTO SUNDAY MORNING AS
THE LOW CENTER TRACKS ACROSS THE NORTHERN PART OF THE STATE SO ANY
SNOW WOULD LIKELY TURN OVER TO RAIN. AN INCH OR TWO OF SNOW MAY FALL
ACROSS THE NORTHERN PART OF THE STATE BEFORE THE CHANGE OVER WITH
THE GREATEST CHANCES FOR SOME ACCUMULATION OVER ELEVATIONS ABOVE 700
FT. PRECIPITATION WILL END SUNDAY MORNING. ANOTHER SURGE OF CHILLY
AIR WILL FOLLOW THE SYSTEM EARLY NEXT WEEK AS HIGH PRESSURE BUILDS
IN FROM CANADA.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA
AND THEN VFR RIGHT INTO WEDNESDAY.
SHORT TERM: CONDITIONS ARE EXPECTED TO IMPROVE TO VFR WEDNESDAY
NIGHT THEN BE VFR ON THURSDAY. CONDITIONS MAY LOWER TO MVFR IN
STRATOCUMULUS CLOUDS ACROSS THE NORTH LATE THURSDAY INTO THURSDAY
NIGHT AND REMAIN VFR DOWNEAST. VFR CONDITIONS ARE EXPECTED FRIDAY
INTO SATURDAY. CONDITIONS WILL THEN LOWER TO IFR IN PRECIPITATION
SATURDAY NIGHT.
&&
.MARINE...
NEAR TERM: SCA TO STAY UP THROUGH MIDNIGHT. GUSTS ARE UP TO 20KT
ATTM W/SEAS NOW UP TO 4 FT AS OF 18Z OBS. EXPECTING GUSTS TO 25KT
THROUGH MIDNIGHT AND THEN GRADIENT IS EXPECTED TO WEAKEN AS THE
COLD FRONT PASSES THROUGH THE WATERS. SW WINDS EXPECTED TO SHIFT
TO THE WNW LATER TONIGHT INTO WEDNESDAY. WINDS WILL DROP OFF TO 10
KT BY 12Z WEDNESDAY W/SEAS DROPPING OFF TO LESS THAN 3 FT.
SHORT TERM: A STRONG SCA OR POSSIBLY A GALE WILL BE NEEDED FOR
GUSTY WEST WINDS ON THURSDAY. AN SCA WILL LIKELY BE NEEDED
THURSDAY NIGHT. WINDS SHOULD THEN BE BELOW SCA FRIDAY AND
SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HEWITT/BLOOMER
MARINE...HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
126 PM EDT TUE OCT 22 2013
.SYNOPSIS...
A COLD FRONT IS THEN EXPECTED TO MOVE ACROSS THE REGION THIS
EVENING. ANOTHER WEAK LOW PRES WILL MOVE EAST...NORTHEAST FROM THE
MID ATLANTIC STATES TO SOUTH OF NOVA SCOTIA ON WEDNESDAY.&&
.NEAR TERM /THROUGH TONIGHT/...
125 PM UPDATE...ADJUSTED THE PRECIP CHANCES TO ALIGN W/THE LATEST
RADAR TRENDS SHOWING 2 AREAS OF SHOWERS W/ONE AREA MOVING ACROSS
WASHINGTON COUNTY AND THE OTHER AREA(MORE OF A LINE) MOVING INTO
NORTHERN AND CENTRAL MAINE AHEAD OF THE COLD FRONT. THIS AREA
APPEARS TO BE ALIGNED W/A PRE-FRONTAL TROF AS INDICATED BY THE 16Z
SFC ANALYSIS. VELOCITY FIELDS INDICATE GUSTS TO 40 KTS AT 5KT FT.
THEREFORE, INCREASED WIND GUSTS THIS AFTERNOON TO 30 MPH AND MOVED
THREAT OF THUNDER S OF A CARIBOU TO BAXTER STATE LINE. THIS BASED
ON LATEST LAPS SOUNDINGS SHOWING ANY INSTABILITY S OF THE LINE.
PREVIOUS DISCUSSION... SOUTH FLOW WILL INCREASE AHEAD OF THE
APPROACHING FRONT, USHERING IN MOISTURE AND RELATIVELY MILD AIR.
THE GFS AND NAM INDICATE LAPSE RATES AROUND 6.5C/KM AND 0-6KM
SHEAR RUNNING AROUND 40 KT, BOTH OF WHICH WOULD HELP CONVECTION
SET UP. ALSO NOTE THAT THE LATEST HRRR HINTS AT A LINE OF HIGHER
REFLECTIVITY COINCIDENT WITH THE FRONT THIS AFTERNOON. HAVE
THEREFORE LEFT ISOLATED THUNDER IN THE FORECAST FOR THIS AFTERNOON
FOR MUCH OF THE FORECAST AREA, THOUGH DOWNEAST AREAS HAVE THE BEST
CHANCES OF ACTUALLY SEEING ANY THUNDERSTORMS. GIVEN THE
AFOREMENTIONED SHEAR, GUSTY WINDS WILL BE POSSIBLE IN ANY OF THE
STRONGER ACTIVITY, REGARDLESS OF WHETHER OR NOT THERE IS THUNDER.
OVERALL, EXPECT ABOUT A THIRD OF AN INCH OF RAIN AT MOST, WITH
MUCH OF THE AREA SEEING LESS THAN A QUARTER OF AN INCH BY TONIGHT.
FOR TONIGHT...THE FRONT WILL EXIT INTO NEW BRUNSWICK THIS EVENING,
WITH THE RAIN COMING TO A QUICK END THEREAFTER. MUCH COOLER AND
DRIER AIR WILL FOLLOW IN THE FRONT`S FOOTSTEPS, LEADING TO CLEARING
SKIES AND COOLING TEMPERATURES. OVERNIGHT LOWS WILL BE IN THE LOWER
30S NORTH, WITH THE USUAL COLD SPOTS ACROSS THE NORTHWEST DROPPING
INTO THE 20S. CENTRAL AND SOUTHERN AREAS WILL SEE MID 30S, WITH THE
COAST BOTTOMING OUT AROUND 40.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
MODELS CONT TO AGREE ON A WEAK LOW PRES SYSTEM WITH AN ALBERTA
CLIPPER LIKE S/WV FROM THE OH VLY MOVG ENE FROM THE MID ATLC
STATES WED TO S OF NOVA SCOTIA WED NGT. THIS SYSTEM WILL BRING
CLDNSS TO THE CNTRL AND DOWNEAST PTNS OF THE FA WED INTO WED EVE
ALG WITH THE POSSIBILITY OF LGT RNFL TO DOWNEAST TO PERHAPS AS FAR
N AS E CNTRL PTNS OF THE FA BY ERLY WED EVE. IN ANY EVENT... THE
BEST POTENTIAL OF RNFL WITH THIS SYS APPEARS TO BE FAR SE ME...
BUT EVEN HERE...6 HRLY QPF AMOUNTS LOOK TO BE LGT...AND THERE MAY
BE EVEN A SHARPER SE TO NW CUT-OFF OF PRECIP THEN WHAT WE INDICATE
WITH THE GFS (ONE OF THE MODELS IN THE BLEND WE USED) LIKELY TO
GENEROUS WITH QPF NWRD INTO ME WHERE LLVL DRY AIR MAY RESULT IN
SIG EVAPORATION. IN ANY EVENT...PRECIP FROM THIS LOW SHOULD EXIT
THE FA LATE WED NGT.
IN THE WAKE OF THIS LOW...MDT TO STRONG LLVL COLD ADVCN WILL BEGIN
ACROSS THE FA ERLY THU AND CONT INTO THU EVE. IN ADDITION...AN UPPER
LVL TROF WILL BRING SC TO SPCLY WRN AND NRN PTNS OF THE FA WITH
THE POSSIBILITY OF RN AND HIER TRRN SN SHWRS. AFT THE PASSAGE OF
THE UPPER TROF LATE THU NGT...WINDS SHOULD SUBSIDE SOMEWHAT AND
SHWRS SHOULD MSLY DISSIPATE TO SCT FLURRIES. BOTH DAY AND NGT TM
TEMPS WILL BE ON THE DECLINE EACH PD OF THE SHORT TERM AS
PROGRESSIVELY COLDER AIR CROSSES INTO THE FA FROM QB PROV.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
OVERALL CONTD CHILLY AND UNSETTLED OVR THE FA THRU THE LONG TERM
WITH SIG BLO NORMAL TEMPS.
FRI CONTS TO LOOK BREEZY AND CHILLY...BUT NOT AS BRISK AS THU.
CANNOT RULE OUT SCT FLURRIES OR SPRINKLES OVR THE W AND N...
BUT EVEN HERE THERE SHOULD BE PARTIAL CLRG FRI NGT AS A WEAK
SFC RIDGE BRIDGES INTO THE FA FROM THE OH VLY. SAT WILL BEGIN
BUT HI AND MID CLDNSS WILL INCREASE FROM THE W LATER IN THE DAY
ANOTHER ALBERTA CLIPPER S/WV MOVES TOWARD THE FA FROM THE GREAT
LKS.
DESPITE THE INITIAL SRLY LLVL WINDS THAT SETS UP WITH THE ONSET
OF PRECIP SAT NGT WITH THIS S/WV...THE COMBO OF EVAPORATIONAL AND
WEAK DYNAMIC COOLING FROM PRECIP FALLING FROM MID CLD LVL MAY
RESULT IN A CHG OVR OF LGT RN TO LGT WET SN LATE SAT NGT/ERLY SUN
MORN OVR NRN PTNS OF THE FA...SPCLY IF THE COLDER 00Z ECMWF
SOLUTION VERIFIES...WHICH IMPLIES A WEAK SECONDARY SPOT LOW ON THE
OCCLUSION PT BY ERLY SUN AFTN. FOR THIS REASON WE INTRODUCE A
CHC OF SN WITH THIS SYSTEM ACROSS THE N AND A MIX OF LGT RN/SN
OVR E CNTRL AND INTERIOR DOWNEAST PTNS OF THE FA LATE SAT NGT/ERLY
SUN MORN... WITH COASTAL DOWNEAST AREAS REMAINING LGT RN DUE TO
THE BL INFLUENCE OF MILD MARINE AIR ADVCTG OVR THIS AREA ON S
WINDS. ATTM...QPF LOOKS TO BE FAIRLY LGT...BUT CANNOT RULE OUT AN
INCH OR TWO OF WET SNFL OVR THE HIER TRRN OF THE NW...WITH LESSER
AMOUNTS S AND E.
ANY STEADY PRECIP SUN MORN SHOULD QUICKLY EXIT E OF THE FA BY
MIDDAY SUN AS THE S/WV TRACKS E OF THE FA...LEAVING MSLY SCT AFTN
RN SHWRS...POSSIBLY STILL MIXED WITH WET SN OVR VERY HIGH TRRN.
FAIR CONDITIONS WITH CLRG OVR THE SRN TWO THIRDS OF THE FA CAN BE
XPCTD SUN NGT WITH CONTD CHILLY CONDITIONS ON MON.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: CONDITIONS WILL GENERALLY BE VFR THROUGH THIS MORNING,
THOUGH MVFR CEILINGS WILL BE LIKELY AT KFVE. SHOWERS WILL BE WINDING
DOWN FOR A BIT THIS MORNING, BUT THEY WILL RETURN THIS AFTERNOON
AS A COLD FRONT MOVES FROM WEST TO EAST. MVFR CEILINGS WILL
PREVAIL (IFR AT KFVE) AT THE NORTHERN TERMINALS, BUT KBGR AND KBHB
SHOULD REMAIN VFR THROUGH THE PERIOD. THE RAIN WILL END SHORTLY
AFTER 00Z, SO EXPECT CLOUDS TO LIFT TO VFR AT ALL SITES BY 06Z.
SHORT TO LONG TERM: VFR XPCTD WED INTO WED EVE FOR NRN TAF SITES
WITH MVFR POSSIBLE FOR DOWNEAST SITES DUE TO LOW CLGS AND
INTERMITTENT LGT RNFL WITH A DISTANT OFFSHORE ATLC LOW PRES SYSTEM.
VFR CONDITIONS SHOULD RETURN FOR DOWNEAST SITES WHILE NRN TAF SITES
BECOME MVFR VERY LATE WED NGT IN BKN-OVC SC AND ANY RN/SN SHWRS
WITH LLVL COLD ADVCN AND THE APCH OF AN UPPER TROF...AND THIS
TREND SHOULD CONT THRU THU NGT...AFT WHICH ALL SITES SHOULD BE VFR
FRI AFT THE PASSAGE OF THE UPPER TROF AND CONT SO THRU SAT.
&&
.MARINE...
NEAR TERM: A SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM NOON
TODAY TO MIDNIGHT TONIGHT. SOUTH WINDS WILL INCREASE THROUGH THE
MORNING HOURS AHEAD OF AN APPROACHING COLD FRONT, BECOMING 15 TO
20 KT WITH GUSTS TO AROUND 25 KT BY LATE AFTERNOON. THIS WILL
ALLOW SEAS TO BUILD TO AROUND 5 FT. CONDITIONS WILL IMPROVE LATE
TONIGHT BEHIND THE FRONT.
SHORT TO LONG TERM: WE STILL XPCT MDT TO STRONG SCA CONDITIONS OVR
OUR WATERS THU INTO THU NGT WITH STRONG LLVL COLD ADVCN BEHIND A
DEVELOPING LOW PRES SYS OVR THE ERN MARITIMES. WINDS AND WVS WILL
DIMINISH BLO SCA CRITERIA ON FRI AS THE LOW MOVES INTO THE OPEN
ATLC...WITH BLO SCA CONDITIONS XPCTD TO LAST THRU SAT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 PM EDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT TUE OCT 22 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND
A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL
LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE
SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH
EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A
BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL
CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED
BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE
IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE
ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE.
WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE
RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET
BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE
BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE
EAST.
TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS
850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR
MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF
SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE
SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING
JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON.
TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO
THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN
850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND
BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR
LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL
INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR
LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EDT TUE OCT 22 2013
THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE
UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL
REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL
BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE
SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS
WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND
THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT
AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND
8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE
EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO
WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH
WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE
NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF
GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER
THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW
FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST).
WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA
LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE
LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR
THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE
LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO
BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A
QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE
TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED
CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE
EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP
PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO
WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS
AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR).
THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER
SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO
THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT
EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ.
THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN
THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN
ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE
AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO
EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO
1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE
SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL
ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER
BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS.
THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS
IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE
SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL
BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS
SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP.
ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT
PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN
PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT
AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE
EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT
NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA
AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS
TO LESSEN.
THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT
AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER
GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO
EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE
ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND
THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA.
FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH
THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING
SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO
SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE
EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION
OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE
NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT
THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST
WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL
HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN
GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER
TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS
LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A
REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST
TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE
DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST
COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED
FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE
AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES
WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE
TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 119 PM EDT TUE OCT 22 2013
EXPECT MVFR WX TO DOMINATE MOST OF THIS FCST PERIOD WITH LAKE EFFECT
SNOW SHOWERS. AT SAW...AS WINDS BACK TO THE WEST IN THE
EVENING...THIS WILL PUSH LAKE EFFECT CLOUDS OUT AND VFR CONDITIONS
WILL CONTINUE OVERNIGHT. AS WINDS PICK UP AGAIN...WEST WINDS PICK UP
AGAIN AND GUSTY WINDS WILL PUSH MVFR CLOUDS BACK IN AGAIN BY MID WED
MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT TUE OCT 22 2013
NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY
AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH.
HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE
NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE
THROUGH THE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
100 PM EDT TUE OCT 22 2013
.AVIATION...
//DISCUSSION...
THE SPREAD OF STRATOCU ACROSS THE TAF SITES HAS DROPPED BKN CIGS TO
3-5 KFT. EXPECTING VFR FOR MOST OF THE PERIOD...EXCEPT A BRIEF DROP
TO MVFR OVERNIGHT IN DETROIT SITES AS A DISTURBANCE IS EXPECTED TO
BRING ISOLATED SHOWERS TO THE AREA. THE CONVECTIVE ELEMENT OF THE
CLOUD DECK WILL DISSIPATE TONIGHT...AROUND THE SAME TIME AN UPPER
WAVE BRINGS PRECIP CHANCES TO SRN SITES. EXPECTING THE 3 NRN SITES
TO CLEAR OUT AS THE CEILING LIFTS AND MORE DRY AIR WILL LEAD TO SCT
VFR FOR MUCH OF WED. COLD AIR INFILTRATING THE REGION WILL LEAD ANY
/UNLIKELY/ PRECIP TO BE A RASN MIX AT MBS EARLY WED.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THIS AFTERNOON INTO
THE OVERNIGHT PERIOD.
&&
.PREV DISCUSSION...ISSUED 347 AM EDT TUE OCT 22 2013
SHORT TERM... TODAY AND TONIGHT
CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL
MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR
MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED
ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND
POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW
LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM
THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO
SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS
TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE
LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO
THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO
SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT
WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS
RECOVER INTO THE MID AND UPPER 40S.
THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS
BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING
THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE
THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE
SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION
OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A
CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO
SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE
AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING
GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE
SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS
REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH
THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL
DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A
CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF
THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD
ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS
INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY
LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE
EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK
LOOK ON TARGET BY SUNRISE WEDNESDAY.
LONG TERM...
LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT
LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE
DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE
MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH
PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN
THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C.
IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS
TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN
WILL TEND TO BE SHUNTED TO OUR SOUTHWEST.
THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED
TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE
HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH
ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST
INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED
AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL
FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV
ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED
WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT
POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE
OHIO VALLEY.
MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE
SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER
CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO
PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS
NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR
CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING
WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S.
SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK
INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT
RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH
PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK
UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN
REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS
GRIP ON THE AREA.
MARINE...
A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY
WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL
LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT
GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN
THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE
SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP
WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE
WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON
TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH
TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND
WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE
WEEK.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM
TUESDAY.
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8
AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
SANILAC...UNTIL 8 AM WEDNESDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MM
SHORT TERM...BT
LONG TERM....JVC
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
110 PM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT TUE OCT 22 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE
UPPER LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA
BEING SHUNTED INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES
DROP SOUTHEAST THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE
MAIN SHORTWAVE OF INTEREST FOR THE SHORT TERM CAN BE SEEN OVER
EASTERN SOUTH DAKOTA... AND IS HELPING TO GENERATE THE LIGHT PCPN
SEEN ON RADAR AND SURFACE OBS OVER FAR SOUTHWEST MINNESOTA...
EASTERN SOUTH DAKOTA... AND NORTHERN IOWA. MOST OF THIS ACTIVITY
LOOKS LIKE IT WILL REMAIN SOUTH OF OUR AREA THIS MORNING... SO
MAINLY JUST MENTIONED SOME FLURRIES OR LOW POPS WITH NO SNOWFALL
ACCUMULATIONS. OTHERWISE... TODAY LOOKS BENIGN ACROSS THE FORECAST
AREA... WITH SOME PEAKS OF SUN INTERSPERSED WITH LINGERING
STRATOCU. WE MAINTAIN SOMEWHAT OF A 925-850MB THERMAL TROUGH OVER
THE AREA TODAY... WHICH SHOULD KEEP PLENTY OF CLOUDS IN PLACE...
AND LATEST 11-3.9 MICRON IMAGERY SHOWS PLENTY OF CLOUDS TO THE
NORTH DROPPING SOUTH WITH TIME. HOWEVER... THERE ARE INDICATIONS
THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE ANTICYCLONIC THIS
AFTERNOON... WHICH COULD WORK TO GENERATE SOME DECENT BREAKS IN
THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY FOR NOW GIVEN
SATELLITE TRENDS AND FORECAST PROFILES... AND WENT WITH MOSTLY
CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT SHORTWAVE
OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS MORNING/S...
AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT INTO
WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN WILL
ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL
MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER
THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND
FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY
SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH
WILL ONCE AGAIN BE QUITE A BIT BELOW NORMAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE OCT 22 2013
EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS
IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST
COAST OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES
REGION. THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP
A CYCLONE ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY
COLD AIR WILL CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST
FOR THE NEXT COUPLE OF DAYS.
MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN
MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY
THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN
STREAM TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE
COAST OF NEWFOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE
NORTHERLY WINDS CURRENTLY IN PLACE ACROSS THE REGION TO BECOME
MORE WESTERLY BY THE END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE
WILL LEAD LEE SIDE WARMING ON THE FOOTHILLS OF THE ROCKIES...AND
THIS WARM AIR WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY
BY FRIDAY. IN FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT
THAT THE SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850.
NOT EXACTLY A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS.
THIS WARM UP WILL BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS
LOW LEVEL WARM AIR ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS
SOUTHERN CANADA...AND DRIVE A WEAK COLD FRONT THROUGH THE REGION.
THIS FRONTAL BOUNDARY WILL EVENTUALLY BECOME ORIENTED
EAST/WEST...AND SET THE STAGE FOR A POTENTIALLY SIGNIFICANT STORM
SYSTEM TO DEVELOP NEXT WEEK OVER THE MIDWEST.
IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP
MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO
MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE
SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW
CLIMATOLOGY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1250 PM CDT TUE OCT 22 2013
STRATOCU CLOUDS CONTINUE TO PLAGUE THE TAF SITES WITH CEILINGS
BETWEEN UPPER-END MVFR AND MINIMAL VFR RANGES. CIGS EXPECTED TO
GRADUALLY LIFT WITH COVERAGE SLOWLY BECOMING SCATTERED TO BROKEN
IN THE LOWEST LAYER WHILE HIGHER CEILINGS REMAIN. STILL SOME
UNCERTAINTY AS TO HOW LONG SOME OF THE LOWER LAYERS/CEILINGS WILL
LINGER BUT SHORT-TERM MODELS PLUS OBSERVATION TRENDING PUTS THE
LOWER CLOUDS IN PLACE THRU MUCH OF THE AFTN BEFORE LIFTING THIS
EVE. MIDLVL CIGS WILL HOLD TNGT THRU TMRW IN THIS PERSISTENT NW
FLOW ALOFT. NO PRECIP EXPECTED AT ANY OF THE TAF SITES...THOUGH
KRWF MAY AGAIN BE SUBJECT SO SOME FLURRIES OR -SHSN BUT CHCS ARE
LOW. WINDS WILL REMAIN NW IN THE 5-10 KT RANGE.
KMSP...CEILINGS TO BOUNCE AROUND THE 3 KFT VFR/MVFR THRESHOLD FOR
A COUPLE OF HOURS OR SO AFTER 22/18Z...BUT WILL EVENTUALLY LIFT
INTO VFR BY LATE AFTN AND REMAIN AS SUCH THROUGHOUT THE REST OF
THIS TAF ISSUANCE. CEILINGS WILL REMAIN ABOVE 1700 FT...SO NO
SIGNIFICANT IMPACTS EXPECTED WITH ADVERTISED CEILINGS. WINDS
STARTING OUT FROM 350 DIRECTION WILL BACK TO 300-320 THIS EVE THRU
TMRW AFTN WITH SPEEDS IN THE 5-10 KT RANGE.
/OUTLOOK FOR KMSP/
THU...VFR. NW WIND 10KT.
THU NIGHT...VFR. NW WIND 10 KT BECMG W.
FRI...VFR. W WIND 5-10 KT BECMG SW 15-20 KT.
FRI NIGHT...MVFR CIGS PSBL LATE. SW WIND 10-20 KT BECMG W.
SAT...MVFR CIGS PSBL EARLY. NW WIND 15-20 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...
SHORT TERM...
LONG TERM...JRB
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS BILLINGS MT
319 PM MDT TUE OCT 22 2013
.SHORT TERM...VALID FOR WED AND THU...
UPPER RIDGE OVER THE WESTERN CONUS WILL REMAIN DOMINANT FOR THE
REGION THROUGH THE SHORT TERM PERIOD...THUS GENERALLY QUIET
WEATHER WILL CONTINUE FOR THE NEXT FEW DAYS. DRY DOWNSLOPE WARMING
HAS ALLOWED FOR TEMPS TODAY TO GET INTO THE 60S...WITH 68 DEGREES
AT LIVINGSTON AT 3PM. WEAK SHORTWAVE IN ALBERTA WILL DROP THROUGH
THE NW FLOW ALOFT AND ALLOW FOR A FRONTAL PASSAGE LATE TONIGHT AND
COOLER CANADIAN AIR TO OOZE INTO OUR AREA FOR TOMORROW...WITH A
SHIFT TO EASTERLY WINDS. ACCOMPANYING THIS FROPA WILL BE ENOUGH
SHALLOW MOISTURE TO BRING A FEW LIGHT SHOWERS OR SPRINKLES TO
MAINLY OUR EAST LATE TONIGHT INTO WEDNESDAY MORNING. COULD BE SOME
STRATUS BACKDOOR INTO OUR CENTRAL PARTS AND PERHAPS FOOTHILLS
WEDNESDAY MORNING...AND WILL NEED TO KEEP WATCH OF THIS...THOUGH
LATEST RAP IS NOT AGGRESSIVE WITH THIS AT ALL. EITHER WAY...EXPECT
COOLER TEMPS WEDNESDAY WITH HIGHS A GOOD 10 DEGREES LESS THAN
TODAY. THIS WILL TRANSLATE TO A CHILLIER WEDNESDAY NIGHT...
ESPECIALLY FOR OUR FAR EAST PER SFC RIDGING AND LOW LEVEL DRYING.
HAVE ADJUSTED LOW TEMPS AND DEWPTS FOR THIS.
COOLISH AIRMASS WITH EAST WINDS WILL PERSIST TO THURSDAY THOUGH
HEIGHTS WILL BEGIN TO RISE AGAIN FROM THE WEST. COULD SEE 60
DEGREES IN OUR WEST THURSDAY AFTERNOON...WITH ONSET OF WEAK LEE
SIDE TROFFING BY THURSDAY NIGHT.
JKL
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
UPPER RIDGING/DRY NW FLOW WILL BE OVER THE REGION THROUGH SAT.
MODELS CONTINUE TO DIG A STRONG SHORTWAVE INTO THE PACIFIC NW SUN
AND SUN NIGHT. THE GFS MAINLY DIGS IT SOUTH OF THE REGION AS AN OPEN
WAVE THROUGH VERY LATE MON. MEANWHILE...THE ECMWF DIGS STRONG
SHORTWAVE/JET ENERGY THROUGH THE REGION SUN NIGHT...DEVELOPING AN
UPPER LEVEL LOW JUST SW OF THE REGION MON...WHERE IT MEANDERS FOR
ABOUT 18 TO 24 HRS BEFORE SLOWLY SINKING SOUTH. BOTH MODELS BRING
PRECIPITATION INTO THE AREA LATE SUN INTO SUN EVENING BEHIND THE
COLD FRONT. 850 MB TEMPERATURES ARE FORECAST TO BE WELL BELOW
ZERO DEGREES C BY 12Z MON. THESE TEMPERATURES WILL REMAIN OVER THE
REGION THROUGH TUE. BOTH MODEL SOLUTIONS BRING STRONG UPPER LEVEL
JET ENERGY/DIVERGENCE AND LOW/MID LEVEL FRONTOGENESIS THROUGH THE
CWA SUN NIGHT INTO MON...WITH A PROLONGED PERIOD OF UPSLOPE
FLOW...SO A PROLONGED SNOW EVENT IS LOOKING MORE AND MORE LIKELY.
BECAUSE MODELS ARE IN SLIGHTLY BETTER AGREEMENT...I DID INCREASE
THE CHANCE OF SNOW A BIT SUN NIGHT INTO MON...ESPECIALLY IN
FAVORED UPSLOPE REGIONS SUCH AS THE RED LODGE FOOTHILLS...THE
SHERIDAN FOOTHILLS/BIG HORN MTNS AND SOUTHEAST MONTANA FROM BIG
HORN COUNTY E TOWARDS POWDER RIVER COUNTY. STILL...IT IS SEVERAL
DAYS OUT...SO THERE REMAINS A GOOD DEAL OF UNCERTAINTY WITH THIS
POTENTIAL SNOW EVENT.
DID RAISE TEMPS A FEW DEGREES FRI AND SAT WITH UPPER LEVEL
RIDGING LOOKING MORE LIKELY...THUS HIGHS ARE EXPECTED TO REACH
UPPER 50S TO MID 60S. SUN LOOKS TO BE A TRANSITION DAY AS THE
FRONT MOVES THROUGH...WITH UNSEASONABLY CHILLY HIGHS MON...IN THE
20S AND 30S. STC
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE AREA TODAY AND TONIGHT. A
WEAK COLD FRONT WILL SWITCH THE WINDS TO A MORE N TO NE DIRECTION
EARLY WED MORNING...INCREASING THE POTENTIAL FOR AREAS OF MVFR
CEILINGS WED MORNING THROUGH EARLY WED AFTERNOON. STC
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 040/053 033/055 040/063 040/063 038/053 028/032 018/032
00/B 00/U 00/U 00/U 02/W 55/S 41/B
LVM 033/055 029/061 036/063 035/064 035/052 026/034 011/031
00/B 00/U 00/U 00/U 03/W 55/S 32/J
HDN 036/053 029/057 034/064 035/064 038/054 029/034 021/032
00/B 00/U 00/U 00/U 02/W 56/S 41/B
MLS 040/051 028/052 033/062 035/062 038/056 029/034 022/034
02/W 00/B 00/U 00/U 01/B 45/S 31/B
4BQ 038/051 028/053 034/062 036/062 037/057 030/034 023/031
02/W 00/B 00/U 00/U 01/B 45/S 42/J
BHK 037/047 023/047 030/058 034/059 035/054 028/033 021/033
22/W 00/U 00/U 00/U 01/B 34/S 31/B
SHR 036/052 030/058 034/063 033/063 034/056 028/028 013/027
00/B 00/U 00/U 00/U 01/B 56/S 43/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
254 PM CDT TUE OCT 22 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY.
THE FIRST CLIPPER SYSTEM WAS MOVING WELL SOUTHEAST OF THE REGION
THIS AFTERNOON. MEANWHILE...THE NEXT CLIPPER WAS NOTED COMING OUT
OF ALBERTA. 12Z UPPER AIR CHARTS SHOWED ABOUT 20 METER HEIGHT
FALLS AT 500 MB...WITH SATURATION AT 700 MB. THIS WILL CONTINUE TO
DIVE SOUTHEAST...AND COULD BRING SOME PRECIP TO NORTHEAST NEBRASKA
LATE TONIGHT AFTER 09Z...ALTHOUGH LATEST 18Z RUN OF THE RAP AND
12Z ECMWF SUGGEST THAT MEASURABLE PRECIP COULD EVEN HOLD OFF UNTIL
AFTER 12Z IN NORTHEAST NEBRASKA. THERMAL PROFILES SUGGEST THIS
COULD BE A RAIN/SNOW MIXTURE ALONG THE NE/SD BORDER REGION.
CLIPPER THEN CONTINUES TO MOVE EAST SOUTHEAST AND BRINGS PRECIP
CHANCES DOWN THE MISSOURI RIVER THROUGH THE MORNING AND INTO THE
AFTERNOON...WHERE IT COULD BE A RAIN/SNOW MIXTURE EARLY IN THE
MORNING IN NEBRASKA AND NORTHWEST IOWA...BUT AS TEMPS WARM...LIKELY
BECOMING ALL RAIN BY 15Z AND BEYOND. NOT EXPECTING ANY ACCUMULATION
THOUGH...JUST A RAIN/SNOW MIX POSSIBLE. PRECIP CHANCES WILL CONTINUE
TO WIND DOWN THROUGH THE AFTERNOON AND END ALTOGETHER BY WEDNESDAY
EVENING. THE NAM ALSO HAD A SLIGHTLY MORE WESTERN TRACK...WHICH
SEEMED TO BE TOO FAR WEST GIVEN THE PLACEMENT OF THE DYNAMICS.
BEYOND THEN...NO REAL WEATHER CONCERNS AS HIGH PRESSURE SETTLES
ACROSS THE PLAINS. THIS WILL RESULT IN A COUPLE OF COLD NIGHTS
WEDNESDAY NIGHT...AND EVEN A COUPLE OF DEGREES COLDER THURSDAY
THAN WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES. DAYTIME TEMPS DO
REBOUND INTO THE MID/UPPER 50S BY FRIDAY AS SOUTHWEST FLOW RETURNS
TO THE REGION.
DEWALD
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. EXTENDED MODELS MAINTAIN
SIMILAR TRENDS IN BREAKING DOWN THE WESTERN RIDGE OVER THE WEEKEND
AS UPPER WAVE DROPS INTO THE NORTHERN ROCKIES WITH DRY AND GENERALLY
MILD CONDITIONS THROUGH THIS TIME.
PATTERN TURNS MORE ACTIVE EARLY NEXT WEEK. SOME TIMING ISSUES SHOW
UP ON MONDAY WITH COLD FRONT THAT MOVES THROUGH THE AREA WITH A
BLENDED SOLUTION USED FOR THE FORECAST. ECMWF HOLDS A STRONGER UPPER
WAVE FURTHER TO THE NORTHWEST THAN THE MORE PROGRESSIVE AND LESS
AMPLIFIED GFS THROUGH TUESDAY. CHANCE POPS WERE CONTINUED FOR MONDAY
INTO TUESDAY WITH PRECIP TYPE LESS CERTAIN DEPENDING ON TIMING OF
THE COLDER AIR.
FOBERT
&&
.AVIATION...18Z TAFS FOR KOMA...KOFK...KLNK. CIGS ARE VARIABLE
BETWEEN FL009-FL035...SO MAINLY MVFR...WITH SOME PATCHY IFR AND
LOW VFR CIGS. MVFR CONDITIONS ARE EXPECTED TO MIX OUT AND CIGS
WILL BECOME MORE VFR DURING THE 19Z-21Z PERIOD AND CLOUDS SHOULD
SCATTER OUT THIS EVENING. NORTHWEST SURFACE WINDS WILL ALSO BE
VARIABLE...WITH 8-14KT WINDS AT KOFK AND KOMA...AND STRONGER
10-18KT SUSTAINED WINDS WITH HIGHER GUSTS AT KLNK THRU 00Z.
SURFACE HIGH PRESSURE WILL BUILD IN WITH DIMINISHING WINDS. A WEAK
WEATHER DISTURBANCE WILL BRING INCREASING MID CLOUDS AFTER 06Z
WITH A RAIN/SNOW MIX POSSIBLE AT KOFK/KOMA. FOR NOW WILL CONSIDER
MENTIONING A PROB30 IN THOSE TAF WED AM.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
125 PM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT TUE OCT 22 2013
MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS
MORNING AND TEMPERATURES.
CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS
HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA
EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE
CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS
HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE.
MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH
THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE
THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID
DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS
THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE
AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF
THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM
MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE
MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND
PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL
BE THE EXTENT OF THE PRECIPITATION.
THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING
AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND
INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS
DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH
AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT
IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP
TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER
TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE
SOUTHWEST.
SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT
TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL
BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN
THE CLOUDS MOVE THROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 425 AM CDT TUE OCT 22 2013
BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES.
THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE
BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A
BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE
WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA
COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE
LONG TERM.
THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH
FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR
NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS
TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS
MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE
EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT
OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE
JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND
THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE
INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH
TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED
TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD
BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST
HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD
BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE
TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY
SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS
WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW
TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO
NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID
TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY
RISING BY THE OVERNIGHT HOURS.
TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE
REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE
ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL
SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN
ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT
SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A
NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED
SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST
TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY
STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR
ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD
FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG
IT TO OUR EAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 119 PM CDT TUE OCT 22 2013
A BRISK NORTHWEST WIND WILL CONTINUE THROUGH THE AFTERNOON BUT
SHOULD QUICKLY DIE DOWN AFTER SUNSET AND EVEN BECOME LIGHT AND
VARIABLE WITHIN ONE TO TWO HOURS AFTER SUNSET. THE WIND WILL
BECOME MORE SOUTHERLY TO SOUTHWESTERLY BY DAWN ON WEDNESDAY AND
REMAIN FAIRLY LIGHT THROUGH WEDNESDAY MORNING. CLOUDS WILL BE
PRESENT THROUGHOUT THE PERIOD...ALTHOUGH THE CLOUDS SHOULD BE HIGH
ENOUGH TO KEEP CEILINGS VFR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
352 PM EDT TUE OCT 22 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND MOVE THROUGH
THE AREA ON WEDNESDAY. COOL HIGH PRESSURE WILL THEN BUILD INTO THE
AREA THURSDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA
FRIDAY WITH HIGH PRESSURE BUILDING BACK IN FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 335 PM TUESDAY...MID CLOUDS CONTINUE TO STREAM INTO THE
REGION WITH SOME PATCHY LIGHT RAIN. PER THE 3KM HRRR AND 4KM NSSL
WRF AND RAP MODELS...THE BEST CHANCE OF PRECIPITATION WILL OCCUR
DURING THE LATE EVENING AND ESPECIALLY BETWEEN 06Z AND 12Z. WITH A
DRY SUB-CLOUD LAYER...IT WILL TAKE AWHILE FOR THE LOWER LEVELS TO
MOISTEN. QPF TOTALS WILL BE VERY LIGHT...AVERAGING ONLY A FEW
HUNDREDTHS OF AN INCH. WITH MAX TEMPS REMAINING IN THE 60S
TODAY...MINIMUM TEMPS WILL BE COOL TONIGHT WITH LOWS IN THE LOWER
TO MIDDLE 50S OVER MOST AREAS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
AS OF 340 PM TUESDAY...WITH THE FRONT APPROACHING DURING THE
MORNING HOURS ON WEDNESDAY...WILL CONTINUE A SLIGHT CHC OF LIGHT
RAINFALL MAINLY NEAR THE COAST. ONCE AGAIN...QPF TOTALS WILL BE
VERY LIGHT. THE FRONT SHOULD MOVE OFFSHORE BY EARLY AFTERNOON WITH
GUSTY W/WNW WINDS...WITH SKIES BECOMING MOSTLY CLEAR BY 18Z TO 20Z
IN THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS OF 3 PM TUE...HIGH PRES WILL BUILD IN FROM THE WEST WED NIGHT
BRINGING A MUCH COOLER AND DRIER AIRMASS. CAA BRINGS LIGHT MIXING
THROUGH MUCH OF THE OVERNIGHT BUT COULD SEE SOME DECOUPLING LATE
SETTING UP BETTER RADIATIONAL COOLING. EXPECT LOWS TO RANGE FROM
THE UPPER 30S INLAND TO AROUND 50 OBX. WINDS BACK TO THE W THU
AHEAD OF MUCH STRONGER COLD FRONT AND DEEPER SHORTWAVE SET TO MOVE
THROUGH ON FRI. HIGHS SHOULD BE IN THE LOWER 60S THU. LOWS THU
NIGHT WILL GENERALLY BE IN THE LOW 40S TO AROUND 50 OBX. A COLD
BLAST OF ARCTIC AIR WILL ARRIVE ON FRI AS STRONG BUT MOSTLY DRY
COLD FRONT PUSHES THROUGH IN THE MORNING. DID ADD SLIGHT CHANCE
POPS AFTER MIDNIGHT THU NIGHT INTO FRI MORNING AS MODELS SHOWING
LIGHT QPF. MODEL SOUNDING SHOWING MOISTURE CONFINED TO BELOW 700MB
WHILE REMAINING VERY DRY IN THE DENDRITIC GROWTH ZONE SO RAINFALL
AMOUNTS WILL BE LIGHT...GENERALLY LESS THAN 0.05". ARCTIC HIGH
PRES BUILDS INTO THE REGION LATE FRI THROUGH THE WEEKEND. HIGH
TEMPS WILL ONLY CLIMB TO AROUND 55-60 FRI AND SAT...WHICH WILL
BE ABOUT 10-15 DEGREES BELOW CLIMO. EXCELLENT RADIATIONAL COOLING
CONDITIONS EXPECTED WITH CLEAR SKIES...CALM WINDS...AND VERY LOW
TD VALUES WILL ALLOW TEMPS TO PLUMMET WELL DOWN INTO THE LOW TO
MID 30S AWAY FROM THE COAST. WILL LIKELY SEE FROST FOR AREAS AWAY
FROM THE COAST WITH THESE TEMPERATURES. A MODIFYING TREND BEGINS
SUN AS HIGH TRANSLATES EASTWARD THOUGH TEMPS LOOK TO REMAIN BELOW
CLIMO INTO EARLY NEXT WEEK AS BELOW AVG HEIGHTS REMAIN ACROSS THE
EASTERN CONUS.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SHORT TERM /TONIGHT AND WEDNESDAY/...
AS OF 1250 PM TUESDAY...MID LEVEL OVERCAST DOMINATES THE REGION
THIS AFTERNOON BUT CLOUD DECKS SHOULD LOWER LATER THIS EVENING
INTO TONIGHT AS THE SUB-CLOUD LAYER MOISTENS. WILL STAY
CONSERVATIVE FOR NOW AND KEEP CEILINGS AT THE MVFR LEVEL LATE
TONIGHT INTO EARLY WEDNESDAY WITH SPOTTY LIGHT SHOWERS EXPECTED.
SKIES SHOULD CLEAR BY LATE MORNING ON WEDNESDAY AS A STRONG COLD
FRONT SURGES BY THE AREA.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...PRED VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
GENERALLY LIGHT WINDS THU ALTHOUGH ANOTHER STRONG BUT MAINLY DRY
COLD FRONT WILL MOVE THROUGH EARLY FRI WITH STRONG CAA BRINGING
GUSTY NORTHWEST WINDS AGAIN FRI AFTERNOON.
&&
.MARINE...
SHORT TERM /TONIGHT AND WEDNESDAY/...
AS OF 350 PM TUESDAY...WINDS SHOULD BE W/SW TONIGHT AND CONTINUE
MAINLY AT 10 KNOTS OR LESS WITH SEAS GENERALLY 2 TO 3 FEET. STRONG
APPROACHING COLD FRONT ON WEDNESDAY WILL LEAD TO SW WINDS
INCREASING TO 15 TO 20 KNOTS DURING THE MORNING...THEN WITH A GOOD
CAA SURGE BEHIND THE COLD FRONT...EXPECT NORTHERLY WINDS OF 15 TO
20 KNOTS WITH FREQUENT GUSTS TO 25 KNOTS. SEAS WILL RESPOND PER
LOCAL NWPS MODEL...BUILDING TO 5 TO 6 FEET...ESPECIALLY OVER THE
CENTRAL WATERS. GIVEN THE GUSTY WINDS AND BUILDING SEAS...HAVE
INITIATED A SMALL CRAFT ADVISORY FOR ALL WATERS BEGINNING AROUND
16Z ON WEDNESDAY AND CONTINUING INTO WEDNESDAY EVENING/NIGHT.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...ONGOING SCA TO START THE LONG TERM WITH STRONG
HIGH PRES BUILDS IN FROM THE WEST BRINGING FREQUENT GUSTS TO 25KT
ACROSS ALL WATERS/SOUNDS AND SEAS UP TO 6 FT ACROSS THE OUTER
PORTIONS OF THE WATERS. GRADIENTS QUICKLY RELAX THROUGH THE
OVERNIGHT WITH WINDS/SEAS EXPECTED TO DROP BELOW SCA CRITERIA ALL
WATERS BY 10Z. ANOTHER STRONG COLD FRONT WILL MOVE THROUGH THE
WATERS EARLY FRIDAY WITH SCA CONDITIONS ONCE AGAIN POSSIBLE WITH
STRONG CAA. EXPECT NNW WINDS TO INCREASE TO 15-25KT AND SEAS TO
BUILD TO 3-6FT...HIGHEST NORTH OF OCRACOKE. WEEKEND SHOULD FEATURE
LIGHTER WINDS...AOB 15KT...AS CANADIAN HIGH PRES BUILDS OVER THE
AREA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO MIDNIGHT EDT
WEDNESDAY NIGHT FOR AMZ130-135-156-158.
SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 AM EDT THURSDAY
FOR AMZ150-152-154.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...SK
AVIATION...CTC/SK
MARINE...CTC/SK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CDT TUE OCT 22 2013
.UPDATE...
ISSUED AT 1233 PM CDT TUE OCT 22 2013
RADAR RETURNS AND FLURRIES ARE NOW OCCURRING ACROSS THE NORTHERN
RED RIVER VALLEY...AND WILL EXPAND THE FLURRY MENTION EVEN FURTHER
WEST. IN FACT...THE RAP SHOWS POSSIBLE FLURRIES ACROSS MUCH OF THE
REGION THROUGH THE OVERNIGHT HOURS...AND ADJUSTED ACCORDINGLY.
LAKE EFFECT SNOW HAS NEVER MATERIALIZED (WINDS TOO WEAK)...AND
REMOVED THE SCATTERED SNOW SHOWERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 335 AM CDT TUE OCT 22 2013
500 MB UPPER LOW OVER EASTERN LAKE SUPERIOR. STILL HAVE NORTHERLY
FLOW OVER THE AREA BUT WITH WEAK HIGH OVER WESTERN MANITOBA SFC
FLOW IS WEAK AND WITH INVERSION AT 850 MB AND SOME TRAPPED
MOISTURE BELOW THAT CLOUDS WILL BE THE GENERAL RULE THROUGH
WEDNESDAY. SOME BREAKS HERE AND THERE THOUGH. SFC FLOW AROUND LAKE
OF THE WOODS HAVE NOT BE CONDUCIVE FOR ANY LAKE EFFECT SNOW
SHOWERS AS WINDS HAVE BEEN CALM OR VARIABLE UNDER 5 KTS. NOT SURE
ANY CHANGE TODAY...BUT DID KEEP LOW POPS FOR SCT SNOW SHOWERS
AROUND THIS AREA TODAY AS SNOW SHOWERS ARE EVIDENT ON SOUTH END OF
LAKE WINNIPEG OFF CANADIAN RADAR. NO ECHOES SHOWING UP ON DRYDEN
ONT RADAR NEAREST TO LAKE OF THE WOODS REGION.
OTHERWISE...OTHER THAN THE CLOUDS...NEXT CLIPPER TYPE SYSTEM
ENTERING CNTRL ALBERTA WILL TRACK RATHER SIMILAR TO THIS PAST ONE
BUT APPEARS PRETTY WEAK. PREV FCST SEEMED A BIT TOO FAR EAST WITH
PRECIP TONIGHT INTO WED SO TRIMMED BACK A BIT AND EVEN THEN MOST
00Z MODELS KEEP ANY REAL -SN WEST OF OUR FCST AREA. 850 MB TEMPS
CHANGE LITTLE...SO EXPECT ABOUT THE SAME TEMPS FOR HIGHS TODAY AND
WED AS ON MONDAY...BUT DUE TO WARMER START WITH CLOUDS MAYBE A
DEGREE OR TWO WARMER THAN ON MONDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 335 AM CDT TUE OCT 22 2013
UPPER LOW WILL MOVE EAST AND THEN NORTHEAST THRU QUEBEC AND 500 MB
FLOW WILL FLATTEN OVER THE NRN PLAINS/SRN CANADIAN PRAIRIES. 850
MB WARM ADV WILL SPREAD EAST THRU THE RRV WED NIGHT INTO NW MN
THURSDAY. WILL HAVE SOME FLURRIES MENTIONED WITH THIS AS ALL
MODELS PAINT SOME VERY LOW QPF.
FOR FRIDAY THROUGH MONDAY...LONG WAVE UPPER AIR PATTERN DOES NOT
CHANGE MUCH THIS PERIOD. LONG WAVE UPPER LEVEL RIDGE REMAINS OVER
WESTERN NORTH AMERICA AND AN UPPER LEVEL TROUGH REMAINS OVER
EASTERN NORTH AMERICA. EASTERN LONG WAVE TROUGH DOES WEAKEN A BIT
THROUGH THE PERIOD HOWEVER WESTERN RIDGE MAINTAINS ITS INTENSITY.
THE GFS AND ECMWF WERE IN REASONABLE AGREEMENT AT 84 HOURS WITH THE
GFS SLIGHTLY FASTER. UPPER AIR PATTERN SPLITS BY THE END OF THE
PERIOD WITH THE ECMWF FASTER THAN THE GFS WITH THE NORTHERN FLOW AND
THE GFS FASTER THAN THE ECMWF WITH THE SOUTHERN FLOW. WILL BLEND THE
GFS AND ECMWF.
WILL TRIM BACK LOW POPS IN THE FAR NORTHEAST ZONES FRI...SUN AND
TUE.
LITTLE CHANGE TO TEMPS FROM YESTERDAYS RUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1233 PM CDT TUE OCT 22 2013
KIND OF A PERSISTENCE FORECAST THIS TIME AROUND. NOT A HIGH
CONFIDENCE FORECAST IN TERMS OF NAILING CEILING HEIGHTS BUT PRETTY
CONFIDENT IN KEEPING SOME SORT OF CEILINGS AROUND. THERE HAS BEEN A
LOT OF BOUNCING AROUND IN CEILING HEIGHTS THIS MORNING AND AM TRYING
NOT TO CHASE TOO MUCH. WILL GO PREDOMINANT MVFR BUT COULD SEE
BOUNCING BETWEEN VFR AND IFR. HAVE SEEN SOME LOWER VSBYS DUE TO
LIGHT SNOW SHOWERS BUT WILL NOT MENTION ANY AT THIS POINT DUE TO LOW
PROBABILITY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...HOPPES/RIDDLE
AVIATION...GODON
AREA FORECAST DISCUSSION
NWS PORTLAND OR
226 PM PDT TUE OCT 22 2013
.SYNOPSIS...STRONG BLOCKING HIGH PRESSURE RIDGE ALOFT WILL CONTINUE
TO BE THE DOMINANT FEATURE FOR THE NEXT FEW DAYS...WHICH WILL
MAINTAIN STRONG VALLEY INVERSIONS. AN UPPER LOW TRAPPED WITHIN THE
RIDGE DRIFTS TO VANCOUVER ISLAND BY THU AFTERNOON AND THEN REMAINS
NEARLY STATIONARY UNTIL SAT. OFFSHORE LOW-LEVEL FLOW WEAKENS TONIGHT
AND WED. LONGER RANGE MODELS ARE HINTING AT A CHANGE TO A COOLER
REGIME LATE IN THE WEEKEND AND EARLY NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY...
THE LARGE-SCALE PATTERN REMAINS UNCHANGED...WITH A STRONG UPPER LEVEL
RIDGE CENTERED ALONG THE BRITISH COLUMBIA COAST THROUGH ABOUT KAST
AND ALONG THE CASCADES. WATER VAPOR IMAGERY SHOWS A TRAPPED UPPER LOW
AT 43N 130W. THE LARGE-SCALE FEATURES WILL SHOW VERY LITTLE CHANGE
THROUGH THU. THE MAIN CHANGE WILL BE THE TRAPPED LOW. MODELS SHOW IT
DRIFTING TO VANCOUVER ISLAND BY 18Z THU.
THE BIGGER CHANGES WILL OCCUR ON THE SMALLER SCALE. STRATUS SURGE HAS
WORKED ITS WAY TO THE S WA COAST AS OF 20Z...BUT NOT ENOUGH INLAND
PENETRATION TO REACH KTMK. KAST WEBCAMS SHOWING SOME LOW STRATUS JUST
TO THE WEST JUST BEFORE 20Z. 12Z NAM12 MODEL DOES NOT SEEM TO HAVE A
GOOD FEEL FOR THIS LOW-LEVEL MOISTURE...AT LEAST LOOKING AT THE 975MB
LEVEL. OBVIOUSLY THIS MOISTURE IS BELOW 975MB.THE 17Z HRRR 2M RH
FIELD SEEMS TO HAVE A PRETTY DECENT HANDLE ON THE STRATUS. IT SHOWS
THE LOW CLOUDS ALONG THE BEACHES PUNCHING INTO THE MAJOR COASTAL
RIVER DRAINAGES AROUND SUNSET.
THE OTHER SMALL-SCALE FEATURE OF NOTE IS THE OFFSHORE FLOW. THE
KTTD-KDLS GRADIENT WAS AROUND -5.5 MB LATE THIS MORNING. 20Z
SEA-LEVEL PRESSURE READING AT KDLS NOT AVAILABLE DUE TO MAINTENANCE
ON THE SENSOR(S). THE 20Z KPDX-KTTD GRADIENT WAS 1.0 MB...WHICH IS
TYPICALLY TOO HIGH FOR EAST WIND TO SURFACE AT KPDX. CROWN POINT WIND
SENSOR STILL GUSTING TO 45 MPH. NAM MAINTAINS THIS OFFSHORE FLOW
TONIGHT...THEN WEAKENS IT WED. THE COMBINATION OF INVERSIONS AND THE
LOW-LEVEL OFFSHORE FLOW WILL MAKE INLAND TEMPERATURE FORECASTING
SOMEWHAT TRICKY. CASCADES AND HIGHER ELEVATIONS OF THE COAST RANGE
WILL REMAIN BALMY...EVEN AT NIGHT. TEMPERATURES IN VALLEYS...LOWEST
CASCADE FOOTHILLS...AND AREAS AT THE WEST END OF THE GORGE WILL BE
MOST TRICKY.
EXPECT THE STRATUS TO PERSIST ALONG THE COAST AT LEAST WED AND THU.
LEFT IN THE MENTION OF THE POSSIBILITY OF DRIZZLE LATE TONIGHT...
ALTHOUGH IT SEEMS THE BETTER CHANCE MIGHT BE WED NIGHT IF THE MARINE
LAYER CONTINUES TO DEEPEN. A MUDDLED SYNOPTIC PATTERN DEVELOPS THU
NIGHT AND FRI. THE STRAY CUT-OFF LOW CONTINUES TO HANG OUT AROUND
VANCOUVER ISLAND...WHILE A MUCH STRONGER LOW REACHES 37N 132W...WITH
STRONG HIGH PRESSURE ALOFT OVER THE PAC NW. FLAT SURFACE GRADIENTS
THU NIGHT AND FRI WILL HELP TO STRENGTHEN THE INVERSIONS AND ALLOW
VALLEY FOG AND STRATUS COVERAGE TO INCREASE. WEISHAAR
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...EXPECT DRY AND MILD
CONDITIONS TO PREVAIL THROUGH THE WEEKEND AS HIGH PRESSURE REMAINS
IN CONTROL. NIGHT TIME FOG FORMATION WILL BE THE PRIMARY ISSUE FOR
THE AREA THROUGH THE EXTENDED PERIOD. LATE SUNDAY THE UPPER FLOW
BECOMES AMPLIFIED AND MERIDIONAL AS A SHORTWAVE DIGS SOUTH TOWARD
THE GREAT BASIN FROM ALBERTA. AT THIS TIME IT DOES NOT APPEAR THAT
ANY MOISTURE WILL MAKE IT INTO OUR AREA FROM THIS LOW...HOWEVER THE
POTENTIAL IS THERE FOR AN IMPACT ON TEMPERATURES. HOW MUCH OF AN
IMPACT WILL DEPEND ON HOW CLOSE THIS WAVE GETS TO THE COLUMBIA RIVER
GORGE. IF IT PROGRESSES CLOSER THAN CURRENT MODELS DEPICT...THEN
EASTERLY WINDS THROUGH THE GORGE WILL BE STRONGER AND TEMPERATURES
COOLER THAN CURRENTLY FORECAST. HIGH PRESSURE ALOFT RETURNS TUESDAY.
BURGESS
&&
.AVIATION...MOSTLY VFR CONDITIONS PREVAIL THROUGH ABOUT 00Z THIS
EVENING. THE CENTRAL OREGON COAST WILL REMAIN UNDER IFR/LIFR LOW
MARINE CLOUDS...BUT MAY BRIEFLY LIFT TO MVFR FROM 21Z-00Z.
OTHERWISE...OFFSHORE FLOW WEAKENS TONIGHT WHICH WILL ALLOW MORE
EXTENSIVE LIFR LOW CLOUDS/FOG TO DEVELOP ALONG THE COAST AND
INLAND AFTER 06Z.
KPDX AND APPROACHES...VFR THROUGH 06Z. MARINE STRATUS WILL PUSH
ALONG THE COLUMBIA RIVER TONIGHT AS OFFSHORE FLOW WEAKENS...
BRINGING IFR/LIFR STRATUS/FOG AFTER 08Z. /27
&&
.MARINE...LITTLE CHANGE FOR THE MARINE ENVIRONMENT FOR THIS WEEK.
RATHER TRANQUIL WEATHER PREVAILS...WITH WINDS 15 KT OR LESS. SEAS
RUNNING 6 TO 7 FT THROUGH THIS EVENING...BUT WILL SUBSIDE BACK TO
3 TO 5 FT ON WED...AND HOLD AT THAT RANGE THROUGH FRI. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
119 PM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE
ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION
GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR
AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN
SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD
EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A
HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES
EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE
MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES
BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON
HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS
UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S.
ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER
TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM
WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING
HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES
WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT
BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER
THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE
TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF
AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD
THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE
CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF
HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q
VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY
OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF
AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN
ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA
OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY
LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW
WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING
TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST
OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST
CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR
TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA
OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE
AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME
TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP
WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND
11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL
REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF
HIGHS ONLY IN THE 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 AM CDT TUE OCT 22 2013
LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS
TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO
WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY.
ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST
THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS
SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION
AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY
LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL...
WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE
PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND
THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH
HIGHS THURSDAY AGAIN IN THE 40S.
LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE
NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY
NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS
SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT
OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL
CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A
COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING
BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF
OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A
FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA
TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD
HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS
AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK.
MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN
ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER
PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 116 PM CDT TUE OCT 22 2013
CEILINGS WILL CONTINUE TO IMPROVE THROUGH THE AFTERNOON HOURS
SETTLING IN ON THE LOW END SIDE OF VFR. CONDITIONS ARE EXPECTED TO
BECOME PARTLY CLOUDY THIS EVENING...WITH CEILINGS LOWERING INTO
THE MVFR RANGE OVERNIGHT AS ANOTHER FAST MOVING WAVE MOVES THROUGH
THE AREA. APPEARS AS THOUGH THERE IS A LIMITED AMOUNT OF ICE
PRODUCTION IN THE CLOUDS...WHICH SHOULD LIMIT SNOW FALL AMOUNTS
AND REDUCTIONS TO VISIBILITY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...JH
AVIATION...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CDT TUE OCT 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT TUE OCT 22 2013
AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA
NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED
IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD
OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO
MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K
ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST
AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS
RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES
IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A
VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DENDRITIC
GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF
DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS
SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT
CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT
COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE
BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH
OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF
A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN.
FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5
C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS
WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 AM CDT TUE OCT 22 2013
ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE
TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A
RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC
LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH
LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN
30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF
NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND
THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER
EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT
THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN.
AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF
COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES
TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK
TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE
OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO
KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR
FRIDAY NIGHT INTO SATURDAY.
LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT
THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE
TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS...
THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS
WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS
COULD BE OUR FIRST TASTE OF INDIAN SUMMER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1222 PM CDT TUE OCT 22 2013
DEEP...COLD CYCLONIC NORTHWEST FLOW WILL REMAIN OVER THE AREA
THROUGH MUCH OF THE WEEK. THE LOWER LEVEL NORTH AND NORTHWEST FLOW
IN THIS PATTERN WILL PULL INCREASING LOWER LEVEL MOISTURE SOUTHWARD
AND ACROSS THE TAF SITES FOR THIS AFTERNOON INTO WED. CIGS UPSTREAM
ARE MVFR IN THE 1500-2500 FT RANGE. WITH DIURNAL WARMING/MIXING THIS
AFTERNOON...THESE CIGS EXPECTED TO LIFT INTO THE 3000-3500 FT RANGE
BY LATE IN THE DAY. STEEPER LAPSE RATES AND MDT NORTHWEST WINDS IN
THE 925-800MB RANGE TONIGHT SHOULD KEEP CIGS IN THE 3000-3500FT
RANGE OVERNIGHT. MODEL SOUNDINGS AND RH PROGS ALSO INDICATE STRATO-
CU CIGS TONIGHT SHOULD MAINLY BE VFR. LOWER LEVEL MOISTURE INCREASES
EVEN MORE FOR WED BUT MODEL SOUNDINGS CONTINUE TO SHOW STEEP LOW
LEVEL LAPSE RATES AND DEEPER MIXING TO KEEP CIGS MAINLY VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RRS