Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/27/13
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 PM EST THU DEC 26 2013
.SYNOPSIS...
FAST MOVING LOW PRESSURE WILL MOVE OFFSHORE EARLY TONIGHT. A HIGH
PRESSURE RIDGE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
WITH MODERATING TEMPERATURES. LOW PRESSURE WILL MOVE NORTHEAST
FROM THE GULF OF MEXICO...PASSING NEAR NANTUCKET SUNDAY
NIGHT...THEN SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL
INVADE THE REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE IN
NORTHERN MA/SOUTHERN NEW HAMPSHIRE MIDWEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SKIES HAVE CLEARED ACROSS MUCH OF SOUTHERN NEW ENGLAND EARLY THIS
EVENING...BUT THERE WERE STILL SOME CLOUD PATCHES MOVING THROUGH
WESTERN AND CENTRAL MA. WE HAVE ISSUED A SPECIAL WEATHER STATEMENT
ABOUT BLACK ICE THIS EVENING...ESPECIALLY FOR EASTERN CT...RI...AND
EASTERN MA WHERE TEMPS WERE ABOVE FREEZING ALL DAY AND HAVE NOW
BEGUN TO FALL BELOW FREEZING.
WE ARE WATCHING A SMALL BUT INTENSE CLUSTER OF SNOW SHOWERS THAT
HAVE MADE IT AS FAR EAST AS COLUMBIA COUNTY NY AS OF 7 PM. THE
LATEST RAP MODEL SHOWS IT MOVING ACROSS BERKSHIRE COUNTY BUT THEN
FALLING APART. WE HAVE A SLIGHT CHANCE OF A SNOW SHOWER IN THE
GRIDS FOR THE NORTHERN BERKSHIRE FOOTHILLS...BUT MAY NEED TO
EXTEND IT FARTHER SOUTH IF THIS HOLDS TOGETHER.
EXPECT WINDS TO STIR A BIT THROUGH AROUND MIDNIGHT THEN SHOULD
DIMINISH AS H85 WINDS DROP OFF. NOTING H85 TEMPS DROPPING AFTER
MIDNIGHT SO...AS SKIES BECOME MOSTLY CLEAR...SURFACE TEMPS WILL
BOTTOM OUT IN THE UPPER TEENS ACROSS S NH TO AROUND 30 ON THE
OUTER CAPE AND NANTUCKET.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRIDAY...
HIGH PRESSURE WILL BUILD S OF THE REGION...ANOTHER WEAK
SHORT WAVE WILL PASS ACROSS NORTHERN NEW ENGLAND IN THE BROAD LONG
WAVE TROUGH PATTERN IN PLACE ACROSS THE NORTHEAST. THIS FEATURE
WEAKENS FURTHER IN THE W FLOW...SO ALL THAT WILL COME OF IT WILL
BE SOME MID AND HIGH CLOUDS ACROSS CENTRAL AND NORTHERN AREAS.
EXPECT SEASONAL DAYTIME HIGHS...MAINLY IN THE 30S RANGING TO AROUND
40 ON THE S COAST.
FRIDAY NIGHT...
HIGH PRES PASSES S OFF THE MID ATLC COAST WITH WINDS SHIFTING TO
SW. AFTER SOME CLEARING EARLY AT NIGHT...WILL SEE MORE MID AND
HIGH CLOUDS MOVE IN AS A WARM FRONT BEGINS TO APPROACH. AGAIN...
ANOTHER DRY FEATURE SO NO PRECIP IS EXPECTED. OVERNIGHT LOWS WILL
BE IN THE UPPER TEENS AND 20S FOR MOST AREAS...AND 30-35 ALONG THE
S COAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
STRONG STORM SYSTEM SUNDAY NIGHT CAUSING A VARIETY OF WEATHER...
BITTERLY COLD WEATHER MIDWEEK...
SATURDAY...HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND OUT
TO SEA. SOUTHWEST WINDS OVER SOUTHERN NEW ENGLAND HELP USHER MILDER
AIR INTO THE REGION. 850 MB TEMPERATURES WARM ALL THE WAY TO +4C TO
+5C BY EVENING. HIGHS IN THE LOW TO MID 40S. LOWS SATURDAY NIGHT IN
THE 20S TO MID 30S EXCEPT UPPER 30S ON THE ISLANDS.
SUNDAY AND SUNDAY NIGHT...UPPER LEVEL ENERGY WILL HEAD NORTHEAST
FROM THE TENNESSEE VALLEY AND HELP INTENSIFY A LOW PRESSURE SYSTEM
OFF THE NEW JERSEY COAST SUNDAY NIGHT. THE LOW ORIGINATES IN THE
GULF OF MEXICO SATURDAY EVENING AND RACES NORTHEAST TO THE NEW
JERSEY COAST SUNDAY EVENING...THEN CONTINUES RACING TO A POSITION
JUST SOUTH OF NOVA SCOTIA MONDAY MORNING. MODELS HAVE COME INTO
QUITE GOOD AGREEMENT ON THE RAPID INTENSIFICATION OF THIS SYSTEM AS
IT PASSES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT. THE NAM IS
WARMEST AND HAS BEEN DISREGARDED...IN FAVOR MORE OF A ECMWF/ECMWF
ENSEMBLE/GFS/UKMET SOLUTION WHICH IS A TAD FARTHER SOUTHEAST AND
COOLER THAN PREVIOUS SOLUTIONS.
THIS STORM WILL BRING A VARIETY OF IMPACTS. WE WILL BE STARTING OFF
VERY WARM ON SUNDAY...WITH HIGHS IN THE 40S THROUGHOUT THE FORECAST
AREA. RAIN IS FORECAST TO MOVE IN FROM SOUTH TO NORTH IN THE MID TO
LATE AFTERNOON. THE RAIN MAY BECOME HEAVY AT TIMES SUNDAY NIGHT AS
ALL MODELS SHOW VERY STRONG 700 MB OMEGA BETWEEN 00Z AND 03Z MONDAY.
THE 850-700 MB THICKNESS LINE OF 1540...OFTEN DENOTING THE RAIN/SNOW
LINE...IS FORECAST TO STRETCH FROM THE SOUTHERN BERKSHIRES
NORTHEASTWARD TO CAPE ANN AT 00Z. DESPITE ACTUAL WINDS FROM THE
NORTHEAST TO EAST...THE AGEOSTROPHIC SURFACE WIND IS FROM THE NORTH
WHICH COULD LEAD TO MORE LOW-LEVEL COLD AIR DRAINAGE THAN ONE WOULD
OTHERWISE THINK. GFS AND ECMWF SURFACE TEMPERATURES SHOW THE 32
DEGREE LINE A HAIR SOUTH OF THE 1540 THICKNESS LINE...WHICH MAY
SPELL THE POTENTIAL FOR A NARROW SWATH OF FREEZING RAIN. THIS WOULD
BE MOST LIKELY IN CENTRAL MA NORTHEASTWARD THROUGH THE MERRIMACK
VALLEY TO CAPE ANN...PERHAPS AS FAR SOUTHWEST AS THE SPRINGFIELD
AREA. IN NORTHWEST MA AND SOUTHERN NH...ANY RAIN SHOULD TURN
DIRECTLY TO SNOW.
THE FACT THAT THIS IS SUCH A QUICK-HITTING SYSTEM SHOULD WORK TO OUR
BENEFIT. RAINFALL TOTALS IN EASTERN CT/RHODE ISLAND/SOUTHEAST MA
COULD REACH 1 TO 1.5 INCHES. THIS IS NOT ENOUGH TO CAUSE RIVER
FLOODING BUT MAY CAUSE SOME LOCALIZED STORM DRAINAGE TYPE OF
FLOODING. THE DURATION OF ANY FREEZING RAIN WILL ONLY BE ABOUT 2-6
HOURS...AND THUS AMOUNTS WOULD LIKELY ONLY REACH A FEW TENTHS...NOT
ENOUGH FOR A WARNING...BUT AN ADVISORY COULD BE NEEDED. AND AS FOR
SNOW...WE ARE THINKING THAT ACCUMULATIONS IN NW MA AND SOUTHERN NH
COULD REACH A FEW INCHES AFTER THE CHANGEOVER FROM RAIN...BUT ALL
PRECIPITATION WILL BE ENDING FROM SW TO NE ACROSS THE REGION BY 06Z
MONDAY - JUST AFTER MIDNIGHT...SO PROBABLY STAYING JUST BELOW
ADVISORY CRITERIA. OBVIOUSLY...WE WILL HAVE A BETTER HANDLE WITH
THIS SYSTEM AS TIME GETS CLOSER.
MONDAY THROUGH THURSDAY...AFTER THE STORM SYSTEM DEPARTS EARLY
MONDAY...ATTENTION WILL THEN FOCUS ON THE BITTERLY COLD WEATHER
THAT WILL GRIP OUR REGION AROUND THE NEW YEARS HOLIDAY. IN
GENERAL THE WEATHER WILL BE DRY THROUGH THAT PERIOD ALTHOUGH THERE
ARE DIFFERENCES IN TIMING OF WEAK LOW PRESSURE SYSTEMS THAT PASS
EITHER NORTH OF SOUTH OF US ON VARIOUS MODELS. LET/S CALL IT
PARTLY SUNNY BY DAY AND PARTLY CLOUDY BY NIGHT THROUGH THE PERIOD.
THE ONE THING THAT IS FOR SURE IS THAT NORTHWESTERLY FLOW CAUSES
FRIGID AIR TO GRADUALLY SEEP INTO SOUTHERN NEW ENGLAND STARTING
MONDAY AND BY WEDNESDAY AND THURSDAY WE ARE IN THE DEEP FREEZE.
THE GFS HAS THE DEEP FREEZE ARRIVING A DAY LATER AND LASTING
LONGER THAN THE ECMWF. BUT IN EITHER CASE...850 MB TEMPERATURES
EVENTUALLY PLUNGE TO BETWEEN -20C AND -25C...WITH THE POSSIBILITY
OF -30C IN NORTHERN NEW ENGLAND.
WE ARE FORECASTING OVERNIGHT LOWS TO REACH BELOW ZERO IN SOUTHERN
NH ON NEW YEARS EVE/TUE NIGHT/ AND ABOUT 5 BELOW ZERO THERE ON
WEDNESDAY NIGHT. THIS MAY BE EVEN BE TOO CONSERVATIVE. LOWS WILL
REACH THE SINGLE DIGITS AND LOWER TEENS ACROSS THE REST OF
INTERIOR SOUTHERN NEW ENGLAND BOTH NIGHTS...EXCEPT MID TO UPPER
TEENS SOUTH COAST AND LOWER 20S ON THE ISLANDS. WIND CHILL INDICES
COULD REACH 10 TO 15 BELOW ZERO IN THE EARLY MORNING HOURS ON WED
AND THU ACROSS NORTHERN AND WESTERN MA AND IN SOUTHERN NH.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...VFR. ISOLATED MVFR VSBY IN FOG AT KBED SHOULD IMPROVE
BY 02Z. W-NW WIND GUSTS AROUND 25 KT POSSIBLE ALONG S COASTAL
AREAS THROUGH 06Z.
FRIDAY AND FRIDAY NIGHT...VFR. MAY SEE SOME W WIND GUSTS TO 25 KT
ALONG THE COAST FRI.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SATURDAY THROUGH EARLY SUNDAY AFTERNOON...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. WIDESPREAD IFR SUNDAY NIGHT. PRECIPITATION MAY CHANGE TO
ALL SNOW IN NW MA AND SOUTHERN NH EARLY SUNDAY NIGHT. THERE COULD
BE A BAND OF FREEZING RAIN IN CENTRAL AND NORTHEAST MA. RAIN MAY
BE HEAVY AT TIMES IN RI AND SOUTHEAST MA. ALL PRECIPITATION ENDS
SHORTLY AFTER MIDNIGHT MONDAY MORNING. CONDITIONS IMPROVING TO VFR
MONDAY.
TUE...MODERATE TO HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
TONIGHT...W WINDS GUSTING TO AROUND 25-30 KT AS COLDER AIR WORKS
IN. SOME LEFTOVER VSBY RESTRICTIONS AS PRECIP AND PATCHY FOG EXITS
BY 03Z-04Z ACROSS THE EASTERNMOST WATERS. SEAS BUILD UP TO 5-7 FT
ON THE EASTERN OUTER WATERS. SMALL CRAFTS UP FOR MOST WATERS.
WINDS AND SEAS SHOULD START TO DIMINISH ON THE NEARSHORE WATERS
AFTER MIDNIGHT.
FRIDAY-FRIDAY NIGHT...MAY SEE SOME W WINDS GUSTING UP TO 25 KT ON
THE OUTER WATERS THROUGH MIDDAY FRIDAY. SEAS AOA 5 FT WILL LINGER
ON THE EASTERN OUTER WATERS INTO EARLY FRIDAY NIGHT.
OUTLOOK...SATURDAY THROUGH TUESDAY...
MODERATE CONFIDENCE.
SMALL CRAFT ADVISORIES WILL PROBABLY BE NEEDED SAT AS SOUTHWEST
WINDS COULD GUST TO 20 TO 30 KT OVER THE SOUTHERN AND EASTERN
WATERS AND SEAS COULD REACH 5 TO 7 FT OVER THE SOUTHEASTERN OUTER
WATERS.
SUNDAY INTO MONDAY...STRONG COASTAL LOW PRESSURE MOVES UP THE
EAST COAST AND INTENSIFIES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT
REACHING NOVA SCOTIA MONDAY MORNING. WINDS WILL BECOME
SOUTHEAST...THEN NORTHEAST...THEN NORTHWEST AS THE LOW PASSES.
WINDS COULD GUST TO 25 TO 30 KT AT TIMES OVER THE SOUTHEAST
WATERS BUT GALES ARE NOT EXPECTED AT THIS TIME. SEAS WILL BE QUITE
ROUGH...BUILDING UP TO 6 TO 10 FT JUST OFF THE COAST AND TO 12 FT
OVER THE OUTER WATERS SUNDAY NIGHT...SLOWLY SUBSIDING ON MONDAY.
TUESDAY...WINDS AND SEAS SUBSIDE TO BELOW SMALL CRAFT ADVISORY
LEVELS.
TUESDAY NIGHT...THERE IS THE POTENTIAL FOR SOME FREEZING SPRAY
OVER THE WATERS OFF OF NORTHERN MA LATE AT NIGHT AS VERY COLD
TEMPERATURES MOVE OVER THE REGION.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ231>234-
251.
SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR ANZ236.
SMALL CRAFT ADVISORY UNTIL 2 AM EST FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 3 PM EST FRIDAY FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST FRIDAY NIGHT FOR
ANZ254-255.
SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ256.
&&
$$
SYNOPSIS...EVT/GAF
NEAR TERM...EVT/GAF
SHORT TERM...EVT
LONG TERM...GAF
AVIATION...EVT/GAF
MARINE...EVT/GAF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
926 PM EST THU DEC 26 2013
.DISCUSSION...
TONIGHT...PRESSURE GRADIENT TIGHTENED UP A BIT BETWEEN HIGH PRESSURE
STRETCHING ACROSS THE SOUTHEAST STATES AND INVERTED TROUGH
OFFSHORE. THIS WAS PRODUCING A PERIOD OF INCREASED NORTHERLY WINDS
BUT THE SHALLOW COOL AIR WAS QUITE MOIST AND STRATUS HAS ADVECTED
DOWN THE PENINSULA THIS EVENING. THE RAP INDICATES THE NORTHERLY
FLOW PERSISTING THROUGH THE NIGHT BUT SHOWS ENOUGH WIND SO THAT FOG
SHOULD NOT BECOME A BIG PROBLEM. ADDITIONALLY...CONSIDERABLE
MID-UPPER LEVEL CLOUDINESS WILL BE OVERSPREADING THE PENINSULA.
THE RAP AND GFS ONLY SHOW LIGHT PRECIP AMOUNTS ACROSS THE NORTH
WHERE THERE IS A LITTLE MORE ISENTROPIC LIFT ASSOCIATED WITH WEAK
STATIONARY FRONT STRETCHED OUT FROM THE ATLANTIC INTO THE GULF. WE
ONLY HAVE A MENTION OF LIGHT RAINFALL AND 20-30 PERCENT POPS...SO
WILL NOT PLAN ON CHANGING THE CURRENT FORECAST MUCH.
&&
.AVIATION...
INCREASED NORTHERLY WINDS PUSHED A STRATUS DECK DOWN THE PENINSULA
THIS EVENING AND THE MAIN FORECAST PROBLEM IS LONGEVITY OF THE IFR
CEILINGS. MORE LOW LEVEL WIND IS FORECAST THAN LAST NIGHT...SO IT
DOES NOT APPEAR THAT FOG WILL BECOME A BIG PROBLEM. CONSIDERABLE
MID/HIGH CLOUDINESS SEEMS ALSO TO BE A HINDRANCE TO FOG/STRATUS.
SURFACE OBSERVATIONS SHOW CEILINGS MAINLY IN THE FL006-009 RANGE BUT
ONE OR TWO SPOTS HAVE HAD CEILINGS TO FL004. EXPECT THERE TO BE
SOME OSCILLATIONS DUE TO LOW LEVEL WINDS...BUT GENERALLY EXPECT
CLOUD BASES IN THE FL006-012 RANGE.
&&
.MARINE...
TONIGHT-FRI...THE MAIN ISSUE IS THE COOL NORTHERLY WEDGE THAT HAS
SHOT DOWN THE COAST THIS EVENING. THINK THAT THE COASTAL TROUGH WILL
LAST INTO FRI...SO PLAN ON AN EXERCISE CAUTION STATEMENT FOR THE
NEARSHORE ZONES IN THE EVENING UPDATE. THE RAP SHOWS THE PRESSURE
GRADIENT REMAINING SUPPORTIVE OF A SOLID 15 KNOTS OF NORTH/NORTHEAST
WINDS ON FRI...MAINLY FROM THE CAPE NORTHWARD...SO POOR CONDITIONS
FOR SMALL CRAFT MAY CONTINUE THEN.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
LASCODY
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
415 AM EST WED DEC 25 2013
.SHORT TERM...TODAY AND TONIGHT...STRONG SURFACE HIGH TO THE NORTH
WILL MOVE EAST REACHING THE EAST COAST BY THIS EVENING. CURRENT
IR SATELLITE IMAGERY SHOWS A LARGE AREA OF LOW CLOUDS OVER THE
OFFSHORE ATLANTIC WATERS. THESE LOW CLOUDS WILL ADVECT INTO THE
AREA TODAY AND TONIGHT WITH AN INVERTED TROUGH DEVELOPING OVER
THE COASTAL WATERS BY TONIGHT. ISOLATED SHOWERS POSSIBLE OVER THE
WATERS THIS MORNING REACHING THE COASTAL AREAS BY AS EARLY AS THIS
AFTERNOON. SREF...NAM12...AND RAP MODELS ARE THE MOST AGGRESSIVE
AND LOOK TOO FAST WITH THE SHOWERS. HAVE USED A BLEND WITH THE
SLOWER GFS. TEMPERATURES WILL BE COOL AGAIN TODAY DUE TO INCREASING
CLOUDINESS AND ONSHORE WINDS. LOWS TONIGHT WILL NOT BE AS COLD AS
THIS MORNING FOR THE SAME REASONS.
THU...HIGH PRES REMAINS N OF THE AREA AND LOW LEVEL NELY WINDS WILL
CONTINUE TO HELP INFLUX OF LOW LEVEL MOISTURE. LLVL MOISTURE
CONVERGENCE COMBINED WITH WEAK UPPER LEVEL DISTURBANCES WILL ALLOW FOR
A SLIGHT TO CHANCE OF SHOWERS FOR THE AREA BUT FORCING DOES LOOK
FAIRLY WEAK. WILL TWEAK INHERITED POPS DOWN A BIT TO 20-30%.
CONTINUED TO LEAN TOWARD COOLER SIDE OF GUIDANCE MAX TEMPS DUE TO
MOSTLY CLOUDY SKIES AND N-NELY WINDS.
THU NIGHT...MODELS CONTINUE TO PREDICT A SWATH OF MOISTURE ACROSS
THE AREA MAINLY ERN GULF...NE FL AND INTO THE WRN ATLC AS MID AND
UPPER LEVEL FLOW BACKS IN RESPONSE TO AN APPROACHING UPPER TROUGH.
SLIGHTLY BETTER FORCING ALOFT AND INCREASED MOISTURE SUGGESTS
SLIGHTLY HIGHER POPS ACROSS S ZONES BUT WILL KEEP MID CHANCE POPS
GOING...WITH ONLY 10-20% N PORTION. MIN RANGE FROM NEAR 40 N TO
LOWER TO MID 50S S PARTS.
FRI...INCREASED DIVERGENCE ALOFT AT 250 MB ATOP THE COOL N-NE
FLOW...PLENTY OF MOISTURE AVAILABLE (PWAT 1.3 INCHES) AND MID LEVEL
DISTURBANCES INDICATE INCREASED RAIN CHANCES...THOUGH BETTER CHANCES
MAY BE LATTER PART OF THE DAY. USED A BLEND OF AVAILABLE MOS
GUIDANCE DUE TO INCREASED UNCERTAINTY. BEST POPS PAINTED OVER NE FL
AT 50-60% AT THIS TIME. MAX TEMPS WILL BE HELD IN CHECK BY CLOUDS
AND PRECIP WITH UPPER 50S N TO MID 60S S. FRI NIGHT...SHORTWAVE
TROUGHING ACROSS THE LOWER MS VALLEY AND DEEPER SW FLOW ALOFT WILL
CONTINUE TO FEED MOISTURE FROM SW TO NE ACROSS THE FORECAST AREA.
BEING START OF DAY 4 CHOSE TO STAY CONSERVATIVE WITH POPS AND SO
CAPPED THEM AT 50% ACROSS NE FL AND 30-40% OVER SE GA BUT MOS
CURRENTLY SHOWS 60-70% IN SOME LOCATIONS. MINS FCST TO ONLY DECREASE
ABOUT 10 DEG FROM MAX TEMPS FROM FRI.
.LONG TERM...SAT-TUE.
A FAIRLY WET PATTERN SEEMS IN STORE INITIALLY WITH DEEP LAYER
MOISTURE (PWAT 1.5 INCHES) ACROSS NE FL AND SE GA SAT WITH A FAIRLY
STRONG SHORTWAVE TROUGH PROGRESSING ACROSS THE LOWER CONUS DURING
THE WEEKEND...PUSHING OFFSHORE THE E COAST BY LATE SUN NIGHT. FOR
NOW INDICATED RAIN CHANCES IN THE 40-60% RANGE SAT-SUN MORNING AND
TAPERED DOWN TO 20-30% BY SUN AFTN. UNCERTAINTY IS MEDIUM WITH
TIMING OF THE SLOWLY WEAKENING SHORTWAVE AS IT TRANSLATES EWD...WITH
THE GFS A GOOD 12 HRS FASTER. LEFT THUNDER OUT OF FCST FOR NOW WITH
VERY WEAK INSTABILITY. IT DOES LOOK LIKE SOME HEAVIER PRECIP
POTENTIAL IS POSSIBLE DUE TO THE STRENGTH OF THE SHORTWAVE WAVE BUT
TOO EARLY FOR SPECIFICS. BASED ON ECMWF AND GFS MOST PRECIP APPEARS
TO MOVE OUT OF THE AREA BY LATE SUN NIGHT WITH A COOLER AND DRIER
AIRMASS MOVING IN MON AND TUE. A REINFORCED SHOT OF COOL AIR MOVES IN
MON NIGHT AS WELL AND SFC HIGH PRES MOVES THRU GA AND SC ON TUE.
&&
.AVIATION...CURRENTLY VFR CONDITIONS WITH CLEAR SKIES AND NORTH
WINDS AROUND 5 KNOTS. EXPECT STRATOCUMULUS TO ADVECT INLAND
AFFECTING MAINLY SSI AND CRG AROUND 12Z WITH MVFR CIGS. EXPECT
MVFR CIGS TO REACH JAX AND VQQ BY 15Z AND THEN GNV AROUND MIDDAY.
HAVE VCSH AT CRG AND SSI AFTER 22Z WITH THE POSSIBILITY OF IFR
CIGS TONIGHT.
&&
.MARINE...INVERTED COASTAL TROUGH PROGGED BY MODELS TO DEVELOP
OVER THE WATERS BY THIS EVENING. WILL CONTINUE WITH MARGINAL
ADVISORY OVER THE OFFSHORE WATERS TODAY AND CAUTION NEAR SHORE.
INVERTED TROUGH WILL LIKELY CAUSE A DECREASE IN WIND SPEEDS TONIGHT
AND EARLY THURSDAY BELOW ADVISORY LEVELS WITH SEAS REMAINING
ELEVATED. UNFAVORABLE BOATING CONDS LOOK TO EXIST MUCH OF THE PERIOD
WITH N TO NE WINDS GENERALLY IN THE 12 TO 20 KT RANGE AND SEAS
AROUND 3-5 FT NEARSHORE AND 4-7 FT OFFSHORE. SMALL CRAFT ADVY CONDS
LOOK POSSIBLE THU NIGHT INTO SAT AS COASTAL TROUGH REMAINS BEYOND 60
NM AND SFC HIGH PRES PUSHES SEWD TOWARD THE SE COAST PINCHING THE
LOCAL PRES GRADIENT. A QUICK INCREASE IN N-NW FLOW IS POSSIBLE SUN
AS WELL WITH SFC LOW PRES DEVELOPING NEAR OR E OF THE GULF STREAM AS
AN UPPER DISTURBANCE MOVES THROUGH THE AREA...BUT NOT ENOUGH
CONFIDENCE TO GO HIGH ON THE WINDS AT THIS POINT.
RIP CURRENTS: MODERATE RISK WILL CONTINUE THROUGH THE WEEK DUE TO
ELEVATED ONSHORE WINDS AND SEAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 55 41 54 38 / 0 20 20 10
SSI 58 48 56 45 / 20 30 30 30
JAX 59 45 57 45 / 10 30 30 40
SGJ 61 53 61 52 / 10 30 40 50
GNV 64 48 61 46 / 0 20 40 50
OCF 66 49 63 50 / 0 20 40 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ALTAMAHA
SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-
FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.
&&
$$
ZIBURA/SHASHY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
312 AM EST WED DEC 25 2013
...CHILLY CHRISTMAS MORNING FOR WEST CENTRAL AND SOUTHWEST
FLORIDA...
.SHORT TERM /TODAY-FRIDAY/...
CHRISTMAS MORNING BEGINS WITH A CHILL IN THE AIR...AS MUCH OF WEST
CENTRAL AND SOUTHWEST FLORIDA IS IN THE 40S AND 50S. PORTIONS OF
LEVY COUNTY ARE IN THE UPPER 30S TO LOWER 40S...STARTING TO
BELIEVE THAT SOME HIGH CLOUDS COULD PREVENT THE EFFICIENT
RADIATIONAL COOLING PREVIOUSLY EXPECTED. THE FREEZE WARNING FOR
LEVY REMAINS POSTED...AND WILL BE EXAMINED AGAIN IN THE COMING
HOURS AS WE NEAR SUNRISE.
THE STALLED FRONT THAT PASSED THROUGH THE AREA YESTERDAY WILL
BEGIN TO SEEP NORTHWARD...PROVIDING A RETURN OF MOISTURE ALL THE
WAY INTO NORTH FLORIDA BY THE END OF CHRISTMAS DAY. PORTIONS OF
NORTH FLORIDA COULD SEE INCREASING CLOUD COVERAGE...AS ADVERTISED
IN SOME GUIDANCE INCLUDING THE SREF...WHICH COULD KEEP
TEMPERATURES ACROSS THE NATURE COAST IN THE 60S OR LOWER 70S.
OTHERWISE...THE AREA TO THE SOUTH OF THAT CLOUD COVER SHOULD BE
ABLE TO REACH INTO THE 70S BEFORE CLOUDS ASSOCIATED WITH THE
RETURN FRONTAL MOISTURE MOVE IN THIS AFTERNOON.
ONE BENEFIT TO THE CLOUD COVER WILL BE THAT TEMPERATURES ON
CHRISTMAS NIGHT WILL BE A TAD WARMER. AREAS OF THE NATURE COAST
WILL BE IN THE UPPER 40S TO LOWER 50S...WITH AREAS AROUND TAMPA
BAY IN THE MID 50S TO LOWER 60S IN SW FLORIDA. THE ADDITIONAL
MOISTURE WILL ALSO CREATE INCREASING RAIN SHOWER CHANCES...WHICH
TREND INTO A WETTER END TO THE WEEK. MODEL GUIDANCE IS MIXED AS TO
RAIN TIMING...WITH THE 00Z NAM MET MOS KICKING IN THE RAIN CHANCES
MUCH SOONER THAN THE 00Z GFS MAV MOS GUIDANCE. TOOK A MIDDLE OF
THE ROAD APPROACH TO MUCH OF THE FORECAST...TRENDING WET INTO THE
WEEKEND SIMILAR TO PREVIOUS FORECASTS. A MID-LEVEL TROUGH
SWINGING THROUGH THE EASTERN UNITED STATES ON THURSDAY SHOULD
PROVIDE SUPPORT FOR RAIN SHOWERS THURSDAY EVENING THROUGH
THURSDAY NIGHT. COMBINE THAT WITH THE RETREATING FRONT COMING IN
FROM THE SOUTH AND RAIN SHOWER CHANCES SHOULD BE MORE SOLID THAN
THEY WERE WITH THIS LAST FRONT.
THE CLOUDY AND WET PATTERN WILL BE REINFORCED ON FRIDAY THANKS TO
A HEALTHY STREAM OF GULF MOISTURE ALONG WITH THE REMNANT FRONTAL
BOUNDARY. TEMPERATURES COULD BE A BIT TRICKY DEPENDING ON HOW MUCH
CLOUD COVER IS OVER A LOCATION. THE LOCATION OF THE BOUNDARY WILL
PLAY A LARGER ROLE ON FRIDAY...WITH GUIDANCE BRINGING A CONSENSUS
WITH THE PEAK CLOUD COVER SITTING NORTH OF TAMPA BAY. IF THIS
CHANGES...SO DRASTICALLY COULD TEMPERATURES FOR FRIDAY.
WE WISH YOU A MERRY CHRISTMAS AND HOPE THAT YOU ENJOY THE DAY!
.LONG TERM /FRI NIGHT-WEDNESDAY/...
AN U/L RIDGE OVER THE FOUR CORNERS AREA WILL WEAKEN SATURDAY
WHILE A STRONG U/L DISTURBANCE PUSHES SOUTH DOWN THE CALIFORNIA
COAST. ANOTHER U/L DISTURBANCE WILL BE OVER THE LOWER MISSISSIPPI
VALLEY AND WILL MOVE EAST ALONG THE NORTHERN GULF OF MEXICO.
PREVIOUS RUNS HAD THE DISTURBANCE ALONG THE CALIFORNIA COAST
CUTTING OFF AND FORMING A REX BLOCK OFF THE CALIFORNIA COAST.
CURRENT GUIDANCE NOW TRENDING TOWARD DISTURBANCE REMAINING IN
SOUTHERN STREAM FLOW AND DIGGING OVER THE SOUTHWEST U.S. AND BAJA
CALIFORNIA SUNDAY...WITH THE LEAD SOUTHERN STREAM DISTURBANCE OVER
THE LOWER MISSISSIPPI VALLEY MOVING EAST ACROSS THE SOUTHEAST U.S.
AND FLORIDA SATURDAY NIGHT AND SUNDAY. L/W TROUGH ASSOCIATED WITH
MAIN NORTHERN STREAM FLOW WILL BE LOCATED FROM HUDSON BAY SOUTH
THROUGH THE OHIO RIVER VALLEY SUNDAY NIGHT AND MONDAY...WITH QUASI
ZONAL FLOW ACROSS THE GULF OF MEXICO AND FLORIDA IN THE SOUTHERN
STREAM. NORTHERN STREAM TROUGH WILL ROTATE EAST OFF THE EASTERN
SEABOARD MONDAY NIGHT AND TUESDAY WITH ADDITIONAL WEAKER IMPULSES
DROPPING DOWN THE BACKSIDE OF THE TROUGH...WITH THE DISTURBANCE
OVER THE SOUTHWEST U.S. SLOWLY MOVING ACROSS TEXAS...WEAKENING AND
OPENING UP WHILE BEING ABSORBED IN THE NORTHERN STREAM FLOW.
AT THE SURFACE...STATIONARY FRONTAL BOUNDARY WILL BE LOCATED ACROSS
THE CENTRAL FLORIDA PENINSULA FRIDAY NIGHT THROUGH EARLY SUNDAY. AN
INCREASING CHANCE OF SHOWERS ACROSS THE FORECAST AREA FRIDAY NIGHT
AND SATURDAY WHICH WILL BE ENHANCED BY THE APPROACHING U/L
DISTURBANCE. WILL TREND POPS BELOW GUIDANCE AT THIS POINT AS
GUIDANCE HAS BEEN INCONSISTENT WITH AREAL COVERAGE OF RAIN. WEAK
SURFACE LOW MAY DEVELOP ALONG THE FRONTAL BOUNDARY WHICH WOULD
ENHANCE LOW LEVEL CONVERGENCE. AS THE U/L DISTURBANCE MOVES EAST OF
THE AREA ON SUNDAY...IT WILL PUSH THE FRONTAL BOUNDARY SOUTH OF THE
FLORIDA PENINSULA. SURFACE HIGH PRESSURE WILL BUILD OVER WEST
CENTRAL AND SOUTHWEST FLORIDA SUNDAY AND MONDAY IN THE WAKE OF THE
DISTURBANCE WITH SLIGHTLY COOLER DRIER AIR ADVECTING OVER THE AREA.
A WEAK SECONDARY COLD FRONT WILL PUSH ACROSS THE FLORIDA PENINSULA
MONDAY NIGHT REINFORCING THE COOLER DRIER AIRMASS. TEMPERATURES
WILL BEGIN ABOVE CLIMATIC NORMALS SATURDAY AND SUNDAY BUT WILL COOL
TO NEAR CLIMATIC NORMALS MONDAY THROUGH WEDNESDAY.
&&
.AVIATION...
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. VFR CIGS 040-050
SPREADING OVER SOUTHWEST FLORIDA VCNTY RSW/FMY/PGD EARLY THIS
MORNING...AND GRADUALLY LIFTING NORTHWEST TOWARD THE REMAINING
TERMINALS BY THIS AFTERNOON.
&&
.MARINE...
HAVE EXTENDED THE SMALL CRAFT ADVISORY FOR THE SOUTHERN OUTER
WATERS A FEW HOURS...AND HAVE ALLOWED THE OTHERS TO EXPIRE. ISSUED
SCEC FOR TAMPA BAY THANKS TO GUSTY WINDS REPORTED IN AND AROUND
THE BAY...MAINLY IN PINELLAS COUNTY THIS MORNING. WILL CONTINUE TO
MONITOR AND UPDATE PRODUCTS AS NECESSARY.
&&
.FIRE WEATHER...
MOISTURE RETURN TODAY SHOULD MITIGATE ANY FIRE WEATHER CONCERNS
THROUGH THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 59 75 59 / 0 30 30 40
FMY 78 62 82 63 / 10 20 30 30
GIF 73 56 76 57 / 10 20 30 30
SRQ 75 59 77 61 / 0 30 30 40
BKV 72 53 74 58 / 0 10 30 40
SPG 71 60 73 62 / 0 30 30 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR COASTAL
LEVY-INLAND LEVY.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...02/GARCIA
LONG TERM/AVIATION...13/OGLESBY
Area Forecast Discussion
National Weather Service Tallahassee FL
246 AM EST Wed Dec 25 2013
.Near Term [Today]...
The Christmas Day temperature forecast in our area is a bit tricky,
complicated by the arrival of a couple different cloud layers. The
first cloud layer is a low stratus deck that has evolved in the last
6-10 hours just offshore coastal SC, GA, and NE FL. Model guidance
is in good agreement to gradually veer the flow in the 925-850mb
layer to an E-ESE direction by the mid-morning hours, which should
cause the stratus deck and greater low-level moisture to spread
inland from the Atlantic, underneath a pronounced inversion. The
second cloud layer will be a band of increasing cirrostratus that
should gradually lower to around 15-20kft during the day per model
forecast soundings. The consensus is that 500-300mb RH will quickly
spike to around 80% between 18-21z, which should create a veil of
high cloud cover over the area this afternoon. The question, of
course, is whether or not the cloud cover arrives in sufficient time
to significantly limit daytime heating. Confidence would be highest
in this occurring (with the stratus deck advancing from the east)
over SC GA, particularly east of a TVI-ABY line.
The latest runs of the RAP hold temperatures in the mid-upper 40s
all day in our Georgia zones consistent with the idea of an
expanding stratus deck. We did not lower the high temperature
forecast quite that aggressively, but more raw model guidance was
blended in with the usually favored MOS over land to produce highs
mostly in the lower 50s in the northern half of the area. It should
be noted that there is a considerable range of possibilities for
"Day 1" of the forecast. An early arrival of the stratus layer could
realistically produce highs in the 40s in SW GA. Cloud cover that
takes longer to materialize could yield mid-upper 50s in those same
areas. For now we`ve taken a compromise approach and our forecast
generally lies near or just below the model average.
.Short Term [Tonight Through Friday]...
Our forecast area will come under the influence of moistening
southwest flow aloft as the polar jet stream remains well north of
our region. A series of short wave troughs will translate quickly
eastward across the northern CONUS, leaving our area to get "fringe"
effects from these systems as they pass quickly to our north.
Additionally there will be a slow-moving, positively tilted trough
over the western Gulf of Mexico. The result of this pattern is a
rather tricky forecast, as forecasting the timing and interaction of
these systems is often difficult.
The first system will affect our region tonight. Although there will
be an increase in moisture and Q-G forcing, there will likely be
some residual dry layers (as indicated in the forecast soundings),
so our QPF and PoP is low. Moisture and Q-G forcing will gradually
increase again Thursday night and Friday, with a corresponding
increase in PoP. Rain chances will generally be confined to the
region along and south of a line from Valdosta to Cape San Blas, as
north of this line it will probably be too dry for rain. Even where
rain is possible, we expect it to be too stable and the forcing too
weak for thunderstorms. Lows will range from the mid to upper 30s in
our northwest zones to mid 40s in our FL zones. Highs will be in the
upper 50s to lower 60s, unless there are more clouds and rain than
currently forecast.
.Long Term [Friday Night Through Wednesday]...
Some fairly significant changes to the new long term fcst as the
latest run of the ECMWF shows a more potent upper level shortwave
digging down into TX early in the weekend. It now appears that this
system will have just enough punch to potentially give us another
wet weekend with increasing rain chances for Sat. and Sun. Even the
GFS is starting to trend in this direction, so confidence for higher
PoPs is increasing for the beginning of the extended fcst.
Thereafter, however, it appears that the upper level pattern will
become very progressive, with a couple of fast moving shortwave trofs
moving through the region during the early to middle portion of next
week. This should keep conditions on the fair, cool, and dry side
for the remainder of the period, as we usher in the New Year of
2014 on next Wed.
&&
.Aviation...
[Through 06Z Thursday] Model guidance is in very good agreement
that a stratus deck will expand inland over SE GA and NE FL early
this morning, and eventually into parts of the FL Big Bend and SW
GA by midday or early afternoon. This would be most likely to
impact VLD and ABY, with TLH and DHN peripherally affected.
Several short term ensembles have the probability of MVFR CIGS at
ABY and VLD climbing to around 90% by 18z, with lesser values of
50-60% at TLH and DHN. Model forecast soundings show the ceiling
could be as low as 2000 feet. For now, we included a 3000ft -
marginal MVFR - ceiling at the aforementioned TAF sites, gradually
spreading ESE-WNW today.
&&
.Marine...
Winds and seas were below advisory levels this early morning.
However, moderate northeast winds are likely to continue for the
next several days as a series of high pressure systems develop to
our north.
&&
.Fire Weather...
Humidity will moderate from the low levels yesterday for the rest of
the week. Red flag conditions are not expected.
&&
.Hydrology...
Increased flows from rainfall over the weekend continue to progress
through the river system. There is still a possibility that the
Choctawhatchee River at Caryville could reach minor flood stage on
12/27, however measured flows within the Pea and upper Choctawhatchee
Rivers may not be sufficient enough for the lower Choctawhatchee
to flood.
Releases from Woodruff Dam continue and have been increased to
45 kcs this evening and may move to near 50 kcfs on Wednesday. As a
result, Blountstown will reach flood stage on 12/25 and should
remain in the minor flood category for some time.
Elsewhere in the region, the Shoal River in Walton County has
crested and will continue to sharply fall. Modest rises on the
Flint will continue, but should stay at or just below action
levels through the weekend. East of the Flint River drainage area,
rainfall was insufficient to result in any significant rises in
the Withlacoochee or Suwannee River systems.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 57 45 60 42 61 / 0 20 20 20 20
Panama City 60 45 60 46 62 / 0 10 10 10 10
Dothan 52 38 57 38 61 / 0 10 10 10 0
Albany 51 38 57 37 59 / 0 20 20 10 10
Valdosta 55 43 58 41 60 / 0 20 20 20 20
Cross City 66 47 66 47 62 / 0 10 20 40 40
Apalachicola 60 47 61 49 62 / 0 20 20 20 20
&&
.TAE Watches/Warnings/Advisories...
FL...Freeze Warning until 9 AM EST /8 AM CST/ this morning for
Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-
Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-
Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-
Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty-
Madison-South Walton-Washington.
GA...Freeze Warning until 9 AM EST this morning for Baker-Ben Hill-
Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth.
AL...Freeze Warning until 8 AM CST this morning for Coffee-Dale-
Geneva-Henry-Houston.
GM...None.
&&
$$
Near Term...Lamers
Short Term...Fournier
Long Term...Gould
Aviation...Lamers
Marine...Fournier
Fire Weather...Lamers
Hydrology...Godsey
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1206 PM CST WED DEC 25 2013
.DISCUSSION...
330 AM CST
SYNOPSIS...A COUPLE QUICK SNOW SYSTEMS MOVE ACROSS THE REGION
THROUGH TONIGHT WITH 1 TO 2 INCHES EXPECTED PRIMARILY ALONG AND
NORTH OF I-88. A BRIEF WARM UP IS EXPECTED LATE THIS WEEK BEFORE
TEMPERATURES QUICKLY TUMBLE SUNDAY WITH ANOTHER CHANCE OF SNOW. FOR
EXAMPLE HIGH TEMPS SATURDAY WILL BE IN THE MID 30S TO THE LOW 40S
THEN LOW TEMPS SUNDAY NIGHT WILL VARY FROM -6 TO +8 ACROSS THE CWA.
ADDITIONAL CHANCES OF SNOW ARRIVE EARLY NEXT WEEK...WITH TUESDAYS
SYSTEM LOOKING THE MOST IMPRESSIVE.
TODAY AND TONIGHT...
THE LONGWAVE TROUGH AXIS STRETCHES FROM MINNESOTA THROUGH NEW MEXICO
THIS MORNING WITH A SHORTWAVE TRAVELING A BIT QUICKER THAN THE
LARGER WAVE. THE SHORTWAVE IS OVER EASTERN IOWA AND ASSOCIATED WITH
SOME LIGHT RETURNS ON RADAR ALONG THE IL/IA STATE LINE. GUIDANCE
CONTINUES TO BACK OFF ON HOW MUCH SNOW WILL DEVELOP AHEAD OF THE
SHORTWAVE...BUT DECIDED TO KEEP SNOW GOING IN THE FORECAST. TEMPS
HAVE COME UP TO AROUND 20 DEGREES WITH THE DGZ AT OR NEAR THE
SURFACE. FORCING EXTENDS THROUGH THE DGZ FOR A COUPLE OF HOURS WITH
A SATURATED SOUNDING AT THOSE LAYERS. HOWEVER...GIVEN THE DOWN PLAY
IN GUIDANCE AND HOW SNOW IS STRUGGLING TO DEVELOP NOW...LOWERED
STORM TOTAL SNOW AMOUNTS. WENT FOR AN INCH NORTH OF
I-88...ESPECIALLY ALONG THE IL/WI STATE LINE...WITH AN INCH OR LESS
EXPECTED SOUTH OF THAT.
SOUTH TO SOUTHWEST WINDS GUSTING UP TO 20 KT COULD RESULT IN A
LITTLE BLOWING SNOW...BUT NOT OVERLY CONCERNED SINCE ONLY EXPECTING
AN INCH TODAY. THE SNOW THAT DOES FALL WILL BE VERY DRY WITH RATIOS
IN EXCESS OF 20:1. HIGH TEMPS WILL BE AT FREEZING DOWN SOUTH TO THE
MID 20S ALONG THE WI/IL STATE LINE. HOWEVER...WIND CHILLS WILL MAKE
IT FEEL LIKE SINGLE DIGITS ALONG THE WI/IL STATE LINE TO THE TEENS
DOWN SOUTH.
NEXT UP IS THE LOW CURRENTLY STRETCHING FROM HUDSON BAY THROUGH
NORTHWEST MINNESOTA. THE LOW PASSES OVER ONTARIO THIS AFTERNOON
WITH THE UPPER LEVEL TROUGH AXIS PASSING THROUGH THIS AFTN/EVENING.
EXPECTING ANOTHER BATCH OF SNOW SHOWERS TO FORM AHEAD OF THIS AS
WELL. HAVE SNOW ENTERING NORTH CENTRAL IL THIS AFTN WITH A BAND
SPREADING SOUTH EAST THROUGH THIS EVENING. THE DEPTH OF
MOISTURE IN THE DGZ IS MUCH BETTER WITH THIS SECOND DISTURBANCE AND
COULD SEE A QUICK HALF INCH TO INCH THROUGH THIS EVENING. THE
HIGHEST TOTALS ARE AGAIN EXPECTED ALONG THE IL/WI STATE LINE BECAUSE
THE FORCING STARTS OUT FARTHER NORTH AND DOES NOT MOVE INTO IL UNTIL
THE MOISTURE IS OVER INDIANA AND MICHIGAN.
FOR OVERNIGHT DID NOT MAKE ANY MAJOR CHANGES TO GOING LOW TEMPS.
NOT SURE HOW MUCH OF THE AREA WILL HAVE A FRESH SNOWPACK SO TEMPS
MAY HAVE TO BE LOWERED A BIT BY LATER SHIFTS. COLDER AIR ALOFT
MOVES IN BEHIND THE TROUGH AXIS...LESS THAN -8C AT 925 MB...AND
CLOUDS SHOULD THIN LATE TONIGHT. SO UPPER TEENS DOWN SOUTH TO
SINGLE DIGITS ACROSS NORTH CENTRAL IL IS EXPECTED. OVERNIGHT...MIN
WIND CHILLS WILL BE IN THE SINGLE DIGITS DOWN SOUTH TO AS LOW AS
-10F NORTH OF I-88.
THURSDAY AND FRIDAY...
NORTHWEST FLOW ALOFT IS EXPECTED EARLY THURSDAY BUT ANOTHER TROUGH
AXIS ROLLS THROUGH FRIDAY. AT THE SURFACE HIGH PRESSURE BUILDS
ACROSS THE SOUTHERN U.S. WITH ITS RIDGING PASSING OVER THE REGION
THURSDAY AFTN. KEPT A DRY FORECAST GOING FOR THIS PERIOD.
SOUTHWEST FLOW AND WAA RAISE 925 MB TEMPS TO NEAR 0C BY FRIDAY
MORNING...AND THEN TO AROUND +5 BY SATURDAY MORNING. THEREFORE HAVE
TEMPS INCREASING THROUGH FRIDAY TO AROUND 30 ALONG THE IL/WI STATE
LINE TO NEAR 40 ACROSS THE SOUTHERN PORTION OF THE CWA. OVERNIGHT
LOWS FRIDAY LOOK TO BE IN THE 20S.
SATURDAY AND SUNDAY...
THE NEXT WEAK LOW IS PUSHED SOUTH THROUGH THE CWA SATURDAY EVENING
AND NIGHT WITH THE UPPER LEVEL TROUGH AXIS ROTATING THROUGH SUNDAY
NIGHT. THE WARM UP CONTINUES ON SATURDAY...AND TEMPERATURES MAY
HAVE TO BE RAISED FURTHER SINCE GUIDANCE CONTINUES TO SUGGEST 925MB
TEMPS WILL WARM TO +4 TO +8C SATURDAY AFTERNOON. THAT RELATES TO
MAX TEMPS ON SATURDAY OF IN THE MID 30S TO LOW 40S. NOT EXPECTING
ANY PRECIP UNTIL BEHIND THE LOW AND ITS COLD FRONT/UPPER LEVEL
TROUGH AXIS SUNDAY.
FIRST...TEMPERATURES DROP THROUGH THE DAY ON SUNDAY WITH HIGH TEMPS
BEING MET EARLY SUNDAY MORNING. LOOKING AT TEMPS RANGING FROM
SINGLE DIGITS NEAR RFD TO LOW 20S IN NORTHWEST INDIANA BY EARLY
SUNDAY EVENING. SO EXPECTING ANY PRECIP THAT DOES FORM SHOULD BE
SNOW. TEMPS CONTINUE TO FALL WITH 925MB TEMPS AT -15 TO -20C BY
MONDAY MORNING. THEREFORE LOW TEMPS SUNDAY NIGHT WILL RANGE FROM
THE SINGLE DIGITS TO AROUND -5F. NORTHWEST WINDS AROUND 10 KT WILL
CREATE MIN WIND CHILLS BELOW ZERO SUNDAY NIGHT. THE COLDEST AREA
WILL BE NORTH OF I-88 WHERE WIND CHILLS LOWER THAN -20F ARE
POSSIBLE.
FOR SNOW...THE FORCING AND MOISTURE DO NOT SEEM ALL THAT IMPRESSIVE
AT THIS TIME SO NOT EXPECTING ANY MAJOR ACCUMULATION. GFS COBB
OUTPUT AGREES AS IT IS ONLY SHOWING A FEW TENTHS.
EXTENDED...MONDAY AND TUESDAY...
MONDAY REMAINS COLD AS THE UPPER LEVEL COLD AIR LINGERS
OVERHEAD...BUT WINDS TURN WSW AND BEGIN TO USHER IN WARMER AIR ALOFT
MONDAY NIGHT. HIGH TEMPS ON MONDAY WILL BE IN THE SINGLE DIGITS TO
THE LOWER TEENS AND WIND CHILLS DURING THE DAY BELOW ZERO. MIN WIND
CHILLS MONDAY NIGHT WILL ONCE AGAIN BE BELOW ZERO. HIGH PRESSURE
PASSES OVER MONDAY NIGHT WITH ANOTHER CLIPPER ARRIVES TUESDAY. THIS
SYSTEM LOOKS DARE I SAY VIGOROUS...FOR BEING A WEEK AWAY. GUIDANCE
DIFFERS SLIGHTLY SO ONLY UPPED POPS INTO THE CHANCE RANGE...BUT
LOOKING AT LONG RANGE COBB FOR FUN INDICATES SNOWFALL OF A FEW
INCHES.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* UNDER 1500FT CIGS THIS AFTERNOON WITH POSSIBLE TEMPORARY IFR.
* LIGHT ACCUMULATING SNOW MOVING IN LATER THIS AFTERNOON AND EVE.
* SMALL CHANCE FOR LIGHT SNOW/FLURRIES LATE IN THE DAY ON THU.
//DISCUSSION...UPDATED 18Z...
STRATUS OVER THE AREA IS WELL TRAPPED UNDER AN INVERSION THIS
AFTERNOON. THIS WOULD INDICATE THE CONTINUED FLATLINE TREND IN
OBSERVATIONS SHOULD CONTINUE...WITH A CHANCE OF STILL TEMPORARILY
DROPPING TO IFR FOR CHICAGOLAND SITES. AN UPPER LEVEL DISTURBANCE
THAT IS MORE IMPRESSIVE THAN THE ONE EARLY THIS MORNING WILL SWING
OVER NORTHERN IL LATE THIS AFTERNOON THROUGH MID-EVE. IT CURRENTLY
IS PRODUCING AN AREA OF IFR VISBYS ACROSS NORTHERN IA/SOUTHEAST
MN/FAR SOUTHWEST WI. SIMILAR TEMPORARY 1 TO 1 1/2SM VISBYS ARE
EXPECTED IN SNOW ACROSS THE AREA...AS FORCING HOLDS STEADY WITH
THIS FEATURE...AND EVEN SOME INDICATIONS IT INCREASES. CIGS ARE
LIKELY TO BOUNCE AROUND WITHIN THE SNOW...THOUGH PRIMARILY REMAIN
AT OR BELOW 2000 FT. UPPER LEVEL FORCING EASES OUT OF THE REGION
LATE THIS EVE/EARLY OVERNIGHT AND MVFR CIGS ARE EXPECTED TO AS
WELL. THE NEXT IN THE SERIES OF NORTHWEST FLOW CLIPPER SYSTEMS IS
FORECAST TO MOVE OVER THE IL/WI STATE LINE LATE IN THE DAY THU.
WHILE THIS COULD END UP PRODUCING MVFR CIGS AND EVEN LIGHT
SNOW/FLURRIES...ITS TOO SMALL OF A PERTURBATION TO CHASE IN A
POINT FORECAST THIS FAR OUT.
WINDS WILL TURN MORE WNW LATE THIS EVE AS A SURFACE COLD FRONT
MOVES THROUGH. THE WINDS WILL BACK TO THE SSW ONCE AGAIN BY THU
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN CIGS REMAINING BELOW 1500 FT THROUGH 22Z. LOW IN WHETHER
IFR WILL OCCUR.
* HIGH IN SNOWFALL OCCURRING...ESPECIALLY 00Z-02Z. MEDIUM IN
VISIBILITY TRENDS.
* LOW IN ANY LIGHT SNOW/FLURRIES LATE ON THU.
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. POSSIBLE PATCHY MVFR CIGS.
THU THROUGH MON...VFR. SLT CHC -SN ON SUN AS WELL AS MON NIGHT.
TUESDAY...SLT CHC -SN.
MTF/BEACHLER
&&
.MARINE...
302 AM CST
HAZARDOUS WAVES/WINDS WILL FOR THE NEARSHORE WATERS AND MAY ALSO
SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE WATERS THRU
MIDDAY.
SFC RIDGE CENTERED OVER THE OHIO VALLEY CONTINUES TO DRIFT EAST
TOWARDS THE MIDDLE ATLANTIC REGION...STRETCHING NORTH TO QUEBEC.
MEANWHILE A TROUGH OF LOW PRESSURE OVER THE UPPER MIDWEST WILL
SLIDE NORTHEAST TOWARDS CENTRAL ONTARIO THIS MORNING...THEN SLOWLY
LIFT NORTHEAST ACROSS JAMES BAY BY EARLY THURSDAY MORNING. THE
GRADIENT THAT WAS EXPECTED TO DEVELOP AND PRODUCE THE GALES
DEVELOPED BUT REMAINED WELL NORTH OF THE LAKE ACROSS LAKE
SUPERIOR...HOWEVER SOME REPORTS ACROSS THE FAR NORTHERN PORTION OF
LAKE MICHIGAN INDICATE LOW END GALES. SO GIVEN THE REDUCED
CONFIDENCE IN THE GALES AND LACK OF OBSERVATIONS TO SUPPORT
KEEPING THE GALE WARNING GOING...HAVE OPTED TO CANCEL THE GALE
WARNING EARLY. WILL HOWEVER CONTINUE TO MENTION OCCASIONAL GALE
FORCE GUSTS TO 35 KT THROUGH MID MORNING...THEN THE GRADIENT WILL
CONTINUE TO WEAKEN. WINDS WILL STEADILY SHIFT FROM SOUTHWEST TO
WEST BY LATE THIS AFTERNOON...THEN CONTINUE TO DIMINISH TO AROUND
15 TO 25 KT. HAZARDOUS WINDS AND WAVES WILL PERSIST FOR THE
NEARSHORE WATERS AND CONFIDENCE REMAINS HIGH THAT THE SMALL CRAFT
ADVISORY WILL CONTINUE. IT IS POSSIBLE THAT THE SMALL CRAFT
ADVISORY WILL NEED TO BE EXTENDED FOR THE INDIANA NEARSHORE WATERS
AS WINDS TURN WEST...THIS MAY HELP KEEP ELEVATED WAVES LONGER FOR
THIS FAR SOUTHEAST CORNER OF LAKE MICHIGAN.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1123 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 948 AM CST Wed Dec 25 2013
Initial upper wave currently pushing through central Illinois.
Earlier light snow ahead of this wave is now well off to the west.
However, a faster shortwave, currently diving into northwest Iowa,
has been producing some light snow ahead of it, from central Iowa
to western Wisconsin. Morning models showing the bulk of the snow
with this feature tracking just to our north, but the NAM and RAP
models show potential for perhaps a tenth or two of snow north of
I-74 during the evening hours. Have made some updates to the snow
trends in the forecast, namely to add some low PoP`s in the far
northern CWA this evening. Have also removed most of the flurries
after midnight, as the shortwave should be well east of us by that
point. Temperature forecasts generally on track and only needed
some minor tweaks.
Geelhart
&&
.AVIATION...
ISSUED 1123 AM CST Wed Dec 25 2013
IFR conditions spreading southward over the TAF sites late this
morning behind the earlier upper wave. Surface obs showing IFR
ceilings back into central Iowa, just ahead of another fast moving
wave, before ceilings come back up to around 1500-2000 feet. Some
light snow over Iowa expected to track through the northern third
of Illinois late afternoon/early evening. May see some reduced
visibilities at times at KPIA/KBMI from these snow showers. VFR
conditions should start working their way eastward across the area
overnight.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance PoPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance PoPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
949 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 948 AM CST Wed Dec 25 2013
Initial upper wave currently pushing through central Illinois.
Earlier light snow ahead of this wave is now well off to the west.
However, a faster shortwave, currently diving into northwest Iowa,
has been producing some light snow ahead of it, from central Iowa
to western Wisconsin. Morning models showing the bulk of the snow
with this feature tracking just to our north, but the NAM and RAP
models show potential for perhaps a tenth or two of snow north of
I-74 during the evening hours. Have made some updates to the snow
trends in the forecast, namely to add some low PoP`s in the far
northern CWA this evening. Have also removed most of the flurries
after midnight, as the shortwave should be well east of us by that
point. Temperature forecasts generally on track and only needed
some minor tweaks.
Geelhart
&&
.AVIATION...
ISSUED 556 AM CST Wed Dec 25 2013
MVFR clouds will prevail for the first few hours of this TAF
period as a fast moving clipper produces light snow for a period
of an hour or so. Snow has already ended at PIA, and is just
affecting SPI. Over the next 2 hours, BMI, DEC and CMI will see
the snow move through. IFR clouds are poised to develop 2 hours
after the snow ends, based on observation trends upstream. The NAM
and RAP soundings show IFR conditions could persist into the
afternoon, and possibly until near sunset. MVFR conditions could
develop as mixing increases this afternoon, but we generally held
off the return to MVFR clouds until 22-23z.
Some clearing should develop from west to east this evening, as
the drier air returns to lower levels. Clearing could reach PIA as
early as 01z and progress to CMI by 07z.
Winds will be primarily southwest until this evening when they
shift to the west and increase from around 10-12kt to 14-16kt.
Shimon
&&
.PREV DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance PoPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance PoPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
802 AM CST WED DEC 25 2013
.DISCUSSION...
330 AM CST
SYNOPSIS...A COUPLE QUICK SNOW SYSTEMS MOVE ACROSS THE REGION
THROUGH TONIGHT WITH 1 TO 2 INCHES EXPECTED PRIMARILY ALONG AND
NORTH OF I-88. A BRIEF WARM UP IS EXPECTED LATE THIS WEEK BEFORE
TEMPERATURES QUICKLY TUMBLE SUNDAY WITH ANOTHER CHANCE OF SNOW. FOR
EXAMPLE HIGH TEMPS SATURDAY WILL BE IN THE MID 30S TO THE LOW 40S
THEN LOW TEMPS SUNDAY NIGHT WILL VARY FROM -6 TO +8 ACROSS THE CWA.
ADDITIONAL CHANCES OF SNOW ARRIVE EARLY NEXT WEEK...WITH TUESDAYS
SYSTEM LOOKING THE MOST IMPRESSIVE.
TODAY AND TONIGHT...
THE LONGWAVE TROUGH AXIS STRETCHES FROM MINNESOTA THROUGH NEW MEXICO
THIS MORNING WITH A SHORTWAVE TRAVELING A BIT QUICKER THAN THE
LARGER WAVE. THE SHORTWAVE IS OVER EASTERN IOWA AND ASSOCIATED WITH
SOME LIGHT RETURNS ON RADAR ALONG THE IL/IA STATE LINE. GUIDANCE
CONTINUES TO BACK OFF ON HOW MUCH SNOW WILL DEVELOP AHEAD OF THE
SHORTWAVE...BUT DECIDED TO KEEP SNOW GOING IN THE FORECAST. TEMPS
HAVE COME UP TO AROUND 20 DEGREES WITH THE DGZ AT OR NEAR THE
SURFACE. FORCING EXTENDS THROUGH THE DGZ FOR A COUPLE OF HOURS WITH
A SATURATED SOUNDING AT THOSE LAYERS. HOWEVER...GIVEN THE DOWN PLAY
IN GUIDANCE AND HOW SNOW IS STRUGGLING TO DEVELOP NOW...LOWERED
STORM TOTAL SNOW AMOUNTS. WENT FOR AN INCH NORTH OF
I-88...ESPECIALLY ALONG THE IL/WI STATE LINE...WITH AN INCH OR LESS
EXPECTED SOUTH OF THAT.
SOUTH TO SOUTHWEST WINDS GUSTING UP TO 20 KT COULD RESULT IN A
LITTLE BLOWING SNOW...BUT NOT OVERLY CONCERNED SINCE ONLY EXPECTING
AN INCH TODAY. THE SNOW THAT DOES FALL WILL BE VERY DRY WITH RATIOS
IN EXCESS OF 20:1. HIGH TEMPS WILL BE AT FREEZING DOWN SOUTH TO THE
MID 20S ALONG THE WI/IL STATE LINE. HOWEVER...WIND CHILLS WILL MAKE
IT FEEL LIKE SINGLE DIGITS ALONG THE WI/IL STATE LINE TO THE TEENS
DOWN SOUTH.
NEXT UP IS THE LOW CURRENTLY STRETCHING FROM HUDSON BAY THROUGH
NORTHWEST MINNESOTA. THE LOW PASSES OVER ONTARIO THIS AFTERNOON
WITH THE UPPER LEVEL TROUGH AXIS PASSING THROUGH THIS AFTN/EVENING.
EXPECTING ANOTHER BATCH OF SNOW SHOWERS TO FORM AHEAD OF THIS AS
WELL. HAVE SNOW ENTERING NORTH CENTRAL IL THIS AFTN WITH A BAND
SPREADING SOUTH EAST THROUGH THIS EVENING. THE DEPTH OF
MOISTURE IN THE DGZ IS MUCH BETTER WITH THIS SECOND DISTURBANCE AND
COULD SEE A QUICK HALF INCH TO INCH THROUGH THIS EVENING. THE
HIGHEST TOTALS ARE AGAIN EXPECTED ALONG THE IL/WI STATE LINE BECAUSE
THE FORCING STARTS OUT FARTHER NORTH AND DOES NOT MOVE INTO IL UNTIL
THE MOISTURE IS OVER INDIANA AND MICHIGAN.
FOR OVERNIGHT DID NOT MAKE ANY MAJOR CHANGES TO GOING LOW TEMPS.
NOT SURE HOW MUCH OF THE AREA WILL HAVE A FRESH SNOWPACK SO TEMPS
MAY HAVE TO BE LOWERED A BIT BY LATER SHIFTS. COLDER AIR ALOFT
MOVES IN BEHIND THE TROUGH AXIS...LESS THAN -8C AT 925 MB...AND
CLOUDS SHOULD THIN LATE TONIGHT. SO UPPER TEENS DOWN SOUTH TO
SINGLE DIGITS ACROSS NORTH CENTRAL IL IS EXPECTED. OVERNIGHT...MIN
WIND CHILLS WILL BE IN THE SINGLE DIGITS DOWN SOUTH TO AS LOW AS
-10F NORTH OF I-88.
THURSDAY AND FRIDAY...
NORTHWEST FLOW ALOFT IS EXPECTED EARLY THURSDAY BUT ANOTHER TROUGH
AXIS ROLLS THROUGH FRIDAY. AT THE SURFACE HIGH PRESSURE BUILDS
ACROSS THE SOUTHERN U.S. WITH ITS RIDGING PASSING OVER THE REGION
THURSDAY AFTN. KEPT A DRY FORECAST GOING FOR THIS PERIOD.
SOUTHWEST FLOW AND WAA RAISE 925 MB TEMPS TO NEAR 0C BY FRIDAY
MORNING...AND THEN TO AROUND +5 BY SATURDAY MORNING. THEREFORE HAVE
TEMPS INCREASING THROUGH FRIDAY TO AROUND 30 ALONG THE IL/WI STATE
LINE TO NEAR 40 ACROSS THE SOUTHERN PORTION OF THE CWA. OVERNIGHT
LOWS FRIDAY LOOK TO BE IN THE 20S.
SATURDAY AND SUNDAY...
THE NEXT WEAK LOW IS PUSHED SOUTH THROUGH THE CWA SATURDAY EVENING
AND NIGHT WITH THE UPPER LEVEL TROUGH AXIS ROTATING THROUGH SUNDAY
NIGHT. THE WARM UP CONTINUES ON SATURDAY...AND TEMPERATURES MAY
HAVE TO BE RAISED FURTHER SINCE GUIDANCE CONTINUES TO SUGGEST 925MB
TEMPS WILL WARM TO +4 TO +8C SATURDAY AFTERNOON. THAT RELATES TO
MAX TEMPS ON SATURDAY OF IN THE MID 30S TO LOW 40S. NOT EXPECTING
ANY PRECIP UNTIL BEHIND THE LOW AND ITS COLD FRONT/UPPER LEVEL
TROUGH AXIS SUNDAY.
FIRST...TEMPERATURES DROP THROUGH THE DAY ON SUNDAY WITH HIGH TEMPS
BEING MET EARLY SUNDAY MORNING. LOOKING AT TEMPS RANGING FROM
SINGLE DIGITS NEAR RFD TO LOW 20S IN NORTHWEST INDIANA BY EARLY
SUNDAY EVENING. SO EXPECTING ANY PRECIP THAT DOES FORM SHOULD BE
SNOW. TEMPS CONTINUE TO FALL WITH 925MB TEMPS AT -15 TO -20C BY
MONDAY MORNING. THEREFORE LOW TEMPS SUNDAY NIGHT WILL RANGE FROM
THE SINGLE DIGITS TO AROUND -5F. NORTHWEST WINDS AROUND 10 KT WILL
CREATE MIN WIND CHILLS BELOW ZERO SUNDAY NIGHT. THE COLDEST AREA
WILL BE NORTH OF I-88 WHERE WIND CHILLS LOWER THAN -20F ARE
POSSIBLE.
FOR SNOW...THE FORCING AND MOISTURE DO NOT SEEM ALL THAT IMPRESSIVE
AT THIS TIME SO NOT EXPECTING ANY MAJOR ACCUMULATION. GFS COBB
OUTPUT AGREES AS IT IS ONLY SHOWING A FEW TENTHS.
EXTENDED...MONDAY AND TUESDAY...
MONDAY REMAINS COLD AS THE UPPER LEVEL COLD AIR LINGERS
OVERHEAD...BUT WINDS TURN WSW AND BEGIN TO USHER IN WARMER AIR ALOFT
MONDAY NIGHT. HIGH TEMPS ON MONDAY WILL BE IN THE SINGLE DIGITS TO
THE LOWER TEENS AND WIND CHILLS DURING THE DAY BELOW ZERO. MIN WIND
CHILLS MONDAY NIGHT WILL ONCE AGAIN BE BELOW ZERO. HIGH PRESSURE
PASSES OVER MONDAY NIGHT WITH ANOTHER CLIPPER ARRIVES TUESDAY. THIS
SYSTEM LOOKS DARE I SAY VIGOROUS...FOR BEING A WEEK AWAY. GUIDANCE
DIFFERS SLIGHTLY SO ONLY UPPED POPS INTO THE CHANCE RANGE...BUT
LOOKING AT LONG RANGE COBB FOR FUN INDICATES SNOWFALL OF A FEW
INCHES.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* 1000-1500 FT CIGS THROUGH MUCH OF TODAY WITH THE POTENTIAL TO
DIP DOWN TO IFR AT TIMES AFTER 16Z.
* CHANCE FOR LIGHT SNOW THIS AFTERNOON AND EVE.
BEACHLER/MTF
//DISCUSSION...UPDATED 12Z...
BACK EDGE OF CLIPPER CONTINUES TO SLIDE EAST ACROSS THE NORTHERN
IL/NORTHWEST IN AIRFIELDS. REGIONAL RADAR DEPICTION INDICATES THE
BACK EDGE OF THE PRECIP WILL BE NEARING ORD/MDW BETWEEN 12-13Z.
CIGS WILL THEN LINGER ARND LOW END MVFR...POSSIBLY DIP TO IFR MID-
MORNING THRU EARLY AFTN. WINDS REMAIN SOUTHERLY WITH OCCASIONAL
GUSTS TO 15-19KT...SOME DRY AIR EVENTUALLY WORKS BACK INTO THE
AREA MIDDAY AND ALLOWS CIGS TO LIFT SLIGHTLY BUT REMAIN MVFR.
THEN YET ANOTHER CLIPPER IS POISED TO ARRIVE AFT 22Z...WITH LIGHT
SNOW DEVELOPING ARND 00-03Z THUR.
WINDS THEN VEER TO WEST ARND 10-12KT THRU DAYBREAK THUR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN CIGS REMAINING AT OR BELOW 1500 FT THROUGH
EARLY AFTERNOON. LOW CONFIDENCE ON WHETHER IFR WILL BE REACHED.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* LOW/MEDIUM CONFIDENCE IN LGT SNOW DEVELOPING AFT 22Z.
BEACHLER/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. POSSIBLE PATCHY MVFR CIGS.
THU THROUGH MON...VFR. SLT CHC -SN ON SUN AS WELL AS MON NIGHT.
TUESDAY...SLT CHC -SN.
BEACHLER
&&
.MARINE...
302 AM CST
HAZARDOUS WAVES/WINDS WILL FOR THE NEARSHORE WATERS AND MAY ALSO
SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE WATERS THRU
MIDDAY.
SFC RIDGE CENTERED OVER THE OHIO VALLEY CONTINUES TO DRIFT EAST
TOWARDS THE MIDDLE ATLANTIC REGION...STRETCHING NORTH TO QUEBEC.
MEANWHILE A TROUGH OF LOW PRESSURE OVER THE UPPER MIDWEST WILL
SLIDE NORTHEAST TOWARDS CENTRAL ONTARIO THIS MORNING...THEN SLOWLY
LIFT NORTHEAST ACROSS JAMES BAY BY EARLY THURSDAY MORNING. THE
GRADIENT THAT WAS EXPECTED TO DEVELOP AND PRODUCE THE GALES
DEVELOPED BUT REMAINED WELL NORTH OF THE LAKE ACROSS LAKE
SUPERIOR...HOWEVER SOME REPORTS ACROSS THE FAR NORTHERN PORTION OF
LAKE MICHIGAN INDICATE LOW END GALES. SO GIVEN THE REDUCED
CONFIDENCE IN THE GALES AND LACK OF OBSERVATIONS TO SUPPORT
KEEPING THE GALE WARNING GOING...HAVE OPTED TO CANCEL THE GALE
WARNING EARLY. WILL HOWEVER CONTINUE TO MENTION OCCASIONAL GALE
FORCE GUSTS TO 35 KT THROUGH MID MORNING...THEN THE GRADIENT WILL
CONTINUE TO WEAKEN. WINDS WILL STEADILY SHIFT FROM SOUTHWEST TO
WEST BY LATE THIS AFTERNOON...THEN CONTINUE TO DIMINISH TO AROUND
15 TO 25 KT. HAZARDOUS WINDS AND WAVES WILL PERSIST FOR THE
NEARSHORE WATERS AND CONFIDENCE REMAINS HIGH THAT THE SMALL CRAFT
ADVISORY WILL CONTINUE. IT IS POSSIBLE THAT THE SMALL CRAFT
ADVISORY WILL NEED TO BE EXTENDED FOR THE INDIANA NEARSHORE WATERS
AS WINDS TURN WEST...THIS MAY HELP KEEP ELEVATED WAVES LONGER FOR
THIS FAR SOUTHEAST CORNER OF LAKE MICHIGAN.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
556 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance POPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance POPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.AVIATION...
ISSUED 556 AM CST Wed Dec 25 2013
MVFR clouds will prevail for the first few hours of this TAF
period as a fast moving clipper produces light snow for a period
of an hour or so. Snow has already ended at PIA, and is just
affecting SPI. Over the next 2 hours, BMI, DEC and CMI will see
the snow move through. IFR clouds are poised to develop 2 hours
after the snow ends, based on observation trends upstream. The NAM
and RAP soundings show IFR conditions could persist into the
afternoon, and possibly until near sunset. MVFR conditions could
develop as mixing increases this afternoon, but we generally held
off the return to MVFR clouds until 22-23z.
Some clearing should develop from west to east this evening, as
the drier air returns to lower levels. Clearing could reach PIA as
early as 01z and progress to CMI by 07z.
Winds will be primarily southwest until this evening when they
shift to the west and increase from around 10-12kt to 14-16kt.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 AM CST WED DEC 25 2013
.DISCUSSION...
810 PM CST
MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES TO ACCOUNT FOR A
QUICK FALL THIS EVENING...BUT WITH CLOUD COVER THICKENING AND
LOWERING AND WARM AIR ADVECTION STRENGTHENING WOULD ANTICIPATE
STEADY OR RISING TEMPS THE REMAINDER OF THE NIGHT.
FIRST BATCH OF SNOW OVER EASTERN IOWA LOOKS TO BE TAKING AIM ON
MOSTLY WISCONSIN AS VERY DRY AIR (RH AROUND 10% AT 850MB ON 00Z
DVN SOUNDING) IS RESULTING IN A BIG VIRGA STORM OVER NORTHERN
ILLINOIS AT THIS TIME. GUIDANCE STILL INDICATES THAT INCREASING
ASCENT AND CONTINUED MOISTENING FROM TOP DOWN WILL LIKELY RESULT
IN SATURATION AND SNOW DEVELOPING LATER THIS EVENING AND
PARTICULARLY AFTER MIDNIGHT. LATEST SUITE OF GUIDANCE HAS BEEN
INCREASINGLY PESSIMISTIC WITH RESPECT TO QPF AMOUNTS OVER OUR CWA
LATER TONIGHT INTO XMAS MORNING. WOULD NOT TAKE MUCH TO SQUEEZE
OUT A TENTH OF AN INCH OF SNOWFALL SO ONLY GOING TO SCALE BACK
POPS SLIGHTLY OVER CENTRAL AND SOUTHERN PORTIONS OF THE CWA WHILE
MAINTAINING CATEGORICAL. REGARDING SNOWFALL TOTALS...LATEST
GUIDANCE WOULD SUGGEST THAT EVEN AN INCH WOULD BE UNATTAINABLE
WITH THIS SYSTEM EXCEPT FOR FAR NORTHERN COUNTIES. NOT TERRIBLY
KEEN ON MAKING BIG CHANGES ON THIS SHIFT...SO GOING TO JUST GENTLY
SCALE BACK AMOUNTS A BIT RATHER THAN GO WITH WHAT IS LOOKING TO BE
THE MORE LIKELY SCENARIO WHICH IS MOST AREAS GETTING LITTLE MORE
THAN A DUSTING THROUGH CHRISTMAS MORNING.
SECOND SHORTWAVE PIVOTING AROUND THE POLAR VORTEX STILL LOOKS ON
TARGET TO BRING ANOTHER CHANCE OF SNOW SHOWERS LATER TOMORROW
AFTERNOON INTO TOMORROW EVENING...AGAIN ESPECIALLY NORTHERN CWA.
WILL LET THE NIGHT CREW HANDLE ANY GRID ADJUSTMENTS WITH THAT
SYSTEM.
IZZI
//PREV DISCUSSION...
225 PM CST
MAIN FORECAST CONCERNS WILL BE HONING IN ON A PAIR OF DISTURBANCES
BRINGING ACCUMULATING SNOW TONIGHT AND AGAIN DURING THE EVENING
TOMORROW...AS WELL AS TEMPERATURE TRENDS WITH NON-DIURNAL TEMPS
TONIGHT AND BITTER COLD RETURNING EARLY NEXT WEEK.
TODAY AND TONIGHT...
PAIR OF UPPER LEVEL DISTURBANCES EVIDENT ON WATER VAPOR IMAGERY THIS
AFTERNOON...THE FIRST TRANSLATING EAST ACROSS NEBRASKA...WHILE A
SECOND WAVE IS DIGGING ACROSS THE CANADIAN PRAIRIES. THE SOUTHERN
WAVE IS FORECAST TO LIFT ACROSS NRN IL/SRN WI OVERNIGHT. ISENTROPIC
ASCENT INCREASES AHEAD OF THE WAVE LATE THIS EVENING...WITH TOP DOWN
SATURATION GRADUALLY EATING AWAY AT THE VERY DRY AIR MASS CURRENTLY
IN PLACE. MOST MODELS INDICATE THAT PRECIP WILL BEGIN JUST BEFORE
MIDNIGHT OVER NORTH CENTRAL ILLINOIS AND INITIALLY WILL BE MAINLY
CONFINED TO THE TIER OR TWO OF COUNTIES NEAR THE STATE LINE WITH DRY
AIR WINNING OUT OVER AREAS FARTHER SOUTH. COLD TEMPERATURES WITH A
FAIRLY DEEP ISOTHERMAL LAYER THAT EXTEND FROM NEAR THE SURFACE TO
ABOUT 6KFT AND COINCIDES NEAR THE BASE OF THE DENDRITIC GROWTH ZONE
WILL HELP LEAD TO FLUFFIER THAN AVERAGE SNOW RATIOS...17-20:1
INITIALLY PER COBB OUTPUT. BETTER FORCING ASSOCIATED WITH THE UPPER
WAVE WILL BE RIGHT ON THE HEALS OF THIS FIRST WARM ADVECTION BURST
OF SNOW AND WILL LEAD TO SNOW SPREADING SOUTHEAST ACROSS THE
REMAINDER OF THE CWA...INCLUDING THE CHICAGO METRO AREA BY AROUND
3AM CST. DGZ NOT NEARLY AS DEEP OVER REMAINDER OF CWA WITH SLIGHTLY
WARMER TEMPS IN THE LOW/MID LEVELS AND A 2-3KFT DEEP DGZ NEAR THE
TOP OF THE SATURATED LAYER BUT COINCIDING WITH THE BETTER LIFT. THIS
WILL RESULT IN STILL DRY BUT CLOSER TO AVERAGE RATIOS OF 14-16:1.
WITH A BLEND OF NAM/GFS TIMING/QPF THIS EVENING...CONTINUE TO CALL
FOR 1-3 INCHES OF SNOW NORTH OF THE I-88 CORRIDOR...1 TO 2 INCHES
BETWEEN I-88 AND A PONTIAC TO VALPARAISO LINE...AND UP TO AN INCH
SOUTH OF THAT LINE.
IN ADDITION TO ACCUMULATING SNOWFALL...PRESSURE GRADIENT WILL
TIGHTEN BETWEEN A STRONG DEPARTING HIGH CURRENTLY OVERHEAD AND THE
APPROACHING FRONTAL TROUGH. THIS WILL RESULT IN BREEZY CONDITIONS
DEVELOPING OVERNIGHT WITH GUSTS INTO THE 20 TO 25 MPH RANGE. GIVEN
THE DRY NATURE OF THE SNOW...THIS WILL LIKELY CONTINUE TO BLOW SNOW
AROUND AFTER IT FALLS TO THE SURFACE. THE INCREASING SOUTHERLY FLOW
WILL ALSO LEAD TO WARMING TEMPERATURES THROUGH THE OVERNIGHT HOURS
WITH LOWS HAPPENING THIS EVENING. BY DAYBREAK TOMORROW...EXPECT
TEMPERATURES TO WARM INTO THE HIGH TEENS TO LOW 20S.
WEDNESDAY THROUGH FRIDAY...
AFOREMENTIONED NORTHERN WAVE WILL CONTINUE TO DIG INTO THE
MIDWEST...CARVING OUT A TROUGH THAT WILL SHIFT EAST ACROSS THE AREA
LATE WEDNESDAY EVENING. MOISTURE WITH THIS SECOND WAVE IS MORE
SHALLOW...AND WILL BE LOOKING AT CLOSER TO AVERAGE SNOW RATIOS.
QUICK HITTING SYSTEM MAY PRODUCE UP TO AN ADDITIONAL INCH NORTH OF
THE I-88 CORRIDOR WITH LITTLE IF ANY SNOW SOUTH. TEMPERATURES
WEDNESDAY NIGHT A BIT TRICKY...WITH SOME GUIDANCE POINTING AT MUCH
COOLER TEMPS THAN FORECAST...IN FACT SUB ZERO WEST OF THE FOX RIVER
VALLEY. HOWEVER...YET ANOTHER VORT LOBE WILL PIVOT ACROSS THE
AREA...AND WHILE DO NOT EXPECT ANY APPRECIABLE PRECIP WITH THIS
WAVE...IT SHOULD AT LEAST HOLD ONTO CLOUD COVER OVERNIGHT. WITH THE
RIDGE AXIS CENTERED OVER IOWA...DOES NOT APPEAR TO FAVOR A STRONG
RADIATIONAL COOLING SETUP AND WILL DISMISS THE COLDEST GUIDANCE.
RIDGE AXIS WILL ARRIVE OVERHEAD MIDDAY THURSDAY AND SHOULD KEEP
CONDITIONS DRY MOST OF THURSDAY AND FRIDAY. THOUGH AS THE SURFACE
RIDGE BREAKS DOWN LATER THURSDAY AND FRIDAY...WITH THE AREA UNDER
NORTHWEST FLOW WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A EVEN
A WEAK UPPER LEVEL DISTURBANCE TO SQUEEZE OUT SOME LIGHT SNOW...AS
SUGGESTED BY THE NAM. WILL KEEP "SILENT" 10-14 POPS IN THE MEANTIME.
SATURDAY THROUGH TUESDAY...
MODELS HAVE BEEN ADVERTISING A RELATIVELY STRONG CLIPPER SYSTEM TO
IMPACT PRIMARILY THE NORTHERN LAKES REGION OVER THE WEEKEND WITH
SMALL CHANCES FOR SNOW INTO NORTHERN ILLINOIS WITH A STRONG COLD
FRONT SWEEPING ACROSS THE AREA. AHEAD OF THE FRONT ON SATURDAY...
7-8C H85 THERMAL RIDGE WILL ADVECT OVERHEAD. EVEN WITH SOME SNOW ON
THE GROUND...LOCAL UPPER AIR CLIMATOLOGY SUGGESTS THAT MOST AREAS
SHOULD BE ABLE TO GET WELL INTO THE 30S...WITH LOW 40S EVEN A
POSSIBILITY...AN IDEA SUPPORTED BY A CONSENSUS MODEL BLEND. A STRONG
COLD FRONT WILL SWEEP ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY
WITH H85 TEMPS PLUMMETING TO -17 TO -18C BY SUNDAY NIGHT. DEPENDING
ON THE EXACT TIMING THE OF THE FRONT...THIS COULD LEAD TO EARLY
MORNING LOWS SUNDAY WITH TEMPS FALLING THROUGH THE DAY AND
NIGHT...BOTTOMING OUT IN THE LOW SINGLE DIGITS OR EVEN BELOW ZERO
ONCE AGAIN...WITH THE COLD AIR MASS LINGERING INTO THE DAY TUESDAY.
BACK UNDER NORTHWEST FLOW ALOFT...THERE WILL BE PERIODIC CHANCES FOR
LIGHT SNOW EARLY NEXT WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LIGHT SNOW POSSIBLY REDEVELOPS LATE TONIGHT ARND 9Z AND
CONTINUES THRU 12Z.
* VFR CIGS THEN DIMINISH TO LOW END MVFR WITH LGT SNOW
ARRIVAL...THEN BORDERLINE IFR CIGS ARND DAYBREAK THRU MIDDAY.
* MVFR TO VFR CIGS BY LATE WED AFTN.
* ANOTHER PERIOD OF LGT SNOW AFT 23Z THRU 03Z THUR.
BEACHLER
//DISCUSSION...UPDATED 06Z...
CLIPPER SYSTEM CONTINUES TO SLIDE EAST ACROSS THE REGION. REGIONAL
RADAR SHOWS A BREAK IN THE LIGHT SNOW ACROSS NORTHERN IL/NORTHWEST
IN...HOWEVER A SECOND WAVE APPEARS TO BE DEVELOPING AND MAY
REDEVELOP THE LIGHT SNOW ACROSS THE AREA ARND 9-10Z AND CONTINUE
THRU 12Z. CIGS HAVE HELD UP AT VFR CONDS...AND WITH LGT SNOW
REDEVELOPING CIGS SHUD COME DOWN TO LOW END MVFR CONDS. GUIDANCE
THEN CONTINUES TO SUGGEST CIGS WILL HOLD DOWN AT MVFR TO
BORDERLINE IFR CONDS THRU MIDDAY. AS WINDS REMAIN SOUTHERLY WITH
OCCASIONAL GUSTS TO 15-19KT...SOME DRY AIR EVENTUALLY WORKS BACK
INTO THE AREA MIDDAY AND ALLOWS CIGS TO LIFT TO HIGH END MVFR
CONDS. THEN YET ANOTHER CLIPPER IS POISED TO ARRIVE AFT 22Z...WITH
LIGHT SNOW DEVELOPING ARND 00-03Z THUR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE ON REDEVELOPING LGT SNOW AFT 9Z THRU 12Z.
* HIGH CONFIDENCE IN CIGS THRU 12Z...MEDIUM CONFIDENCE IN CIGS AFT
12Z THRU MIDDAY.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* LOW/MEDIUM CONFIDENCE IN LGT SNOW DEVELOPING AFT 22Z.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU THROUGH MON...VFR. SLIGHT CHANCE -SN ON SUN AS WELL AS MON
NIGHT.
&&
.MARINE...
215 PM CST
MAIN CONCERNS FOR THE LAKE ARE GALES DEVELOPING THIS EVENING AND
CONTINUE THROUGH WEDNESDAY MORNING.
HAZARDOUS WAVES/WINDS WILL ALSO DEVELOP FOR THE NEARSHORE WATERS
AND MAY ALSO SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE
WATERS OVERNIGHT THRU DAYBREAK WEDNESDAY.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1153 PM CST Tue Dec 24 2013
.DISCUSSION...
ISSUED 859 PM CST Tue Dec 24 2013
Plan to update forecast to reduce snow chances tonight and
Christmas morning. WAA/isentropic lift ahead of main clipper wave
is rapidly shifting east of the area. This forcing has done little
more than develop a deck of mid clouds locally. Forcing with the
upper wave itself is expected to arrive overnight into the morning
hours. There is currently very little snow occurring with the wave
right now, at least with the portion of the wave likely to impact
central Illinois, and the latest HRRR and 00Z NAM have trended
drier.
Low temperatures for the night have likely already been attained,
with good southerly flow helping temperatures to be steady or
slowly rise through the night. This portion and the remainder of
the short term forecast is in good shape and only minor tweaks are
needed for the latest hourly trends.
Bak
&&
.AVIATION...
ISSUED 1153 PM CST Tue Dec 24 2013
Cigs continue to thicken/lower across the central Illinois
terminals this evening as a clipper system begins to move across
the area. Expect conditions to degrade to MVFR by morning, possibly
aided by some light snow from the clipper. At this point, KPIA and
KBMI appear most likely to see some snow. While cloud conditions
are not entirely clear as the clipper departs later on Christmas
Day, plan to keep most terminals MVFR through the end of the 06Z
TAF valid time.
Bak
&&
.PREV DISCUSSION...
ISSUED 250 PM CST Tue Dec 24 2013
Very few changes needed to the forecast as the models remain
fairly consistent and in pretty good agreement throughout much of
the forecast period. Periodic shots of cold air with no major
storms, followed by brief warm-ups will be the main weather trend
for the upcoming week.
SHORT TERM...Tonight through Thursday
High pressure, which brought sub-zero readings to parts of central
Illinois this morning, was centered in southwest IN early this
afternoon. A southerly wind flow has already developed in
Illinois, and this will continue to increase through the evening
and overnight. The result will be slowly rising temperatures
through the night and into Christmas morning.
A clipper system in the northern Plains and its associated weak
surface low in north central Nebraska will shift to the ESE
tonight, spreading light snow into west central IL mainly after
midnight. The axis of the light snow will shift east of the I-55
corridor around daybreak, with lingering flurries to the west. By
late morning the snow should come to an end in much of east
central Illinois, with some lingering flurries from PIA-DEC-MTO-
Robinson. Most areas can expect around 0.5" or less of snow,
except in locations from Canton to just north of Bloomington where
1.0 to 1.5 inches are likely. The snow should be rather fluffy and
will blow around quite a bit with a southwest wind of 10 to 15 mph.
Partial clearing is then expected in the wake of the clipper
system with temperatures in the lower to middle 30s. Another
clipper system will follow on the heels of the first one later on
Christmas Day, but the measurable snow should stay well north of
central IL. This system will bring central Illinois a glancing
blow of colder air, so highs on Thursday will be a bit cooler
along and north of I-74. The rest of central and SE IL can expect
highs Thursday to be very similar to Wednesday`s.
LONG TERM...Friday through Tuesday
Overall, the medium and long range models are in pretty good
agreement with the mean upper level flow from the weekend into
early next week. By Friday, the upper level trough axis in the
eastern U.S. will breakdown and become flatter/more westerly. This
will allow temperatures to warm slightly Friday, with a nice warm-
up well into the 40s expected Saturday. Locations north of I-74,
however, may have some lingering snow which could keep
temperatures down in the upper 30s.
Both the GFS and European agree that the main longwave trough will
re-establish itself in the eastern U.S. by early next week.
However, they arrive at the solution differently - particularly
Sunday into Monday. The GFS is weaker with the trough early on,
and redevelops the longwave gradually. The European is stronger and
sharper with the shortwaves that carve out the new trough, which
results in a solution of light snow Sunday in the upper Midwest
and northern IL. Low level moisture will be quite low, and due to
the lack of persistence in the European model with this scenario
will hold of on mentionable PoPs for now, and keep the forecast in
the slight chance category.
Both models do agree, however, that another shot of very cold air
is in store for the Midwest by late Sunday and lasting into New
Year`s Eve with lows in the single digits to lower teens, and
highs in the teens to lower 20s.
Miller
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
425 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 145 PM MST THU DEC 26 2013
FRIDAY NIGHT-SUNDAY...CONTINUED WARM AND DRY SATURDAY AHEAD OF AN
UPPER TROUGH THAT MOVES THROUGH SATURDAY NIGHT. ON SUNDAY FORECAST
AREA UNDER NORTHWEST FLOW ALOFT. AHEAD OF THE UPPER TROUGH STRONG
NORTH/NORTHWEST WINDS MOVE IN EARLY SATURDAY AFTERNOON WITH
SUSTAINED SPEEDS AROUND 20-30 MPH WITH HIGHER GUSTS. SOME GUSTY
WINDS CONTINUE THROUGH EARLY SATURDAY NIGHT BEFORE SLOWLY DECREASING
AFTER MIDNIGHT AND THROUGH THE DAY SUNDAY. CANT COMPLETELY RULE OUT
SOME VERY LIGHT PRECIPITATION CHANCES EARLY SATURDAY NIGHT AS BETTER
MOISTURE BUT LIMITED DYNAMICS WITH THE UPPER TROUGH MOVE THROUGH.
AFTER MIDNIGHT MOISTURE QUICKLY MOVES AWAY FROM THE AREA WITH NEAR
ZERO CHANCE ON SUNDAY.
LOWS TONIGHT UPPER TEENS TO MID 20S WITH HIGHS SATURDAY MID 50S TO
LOW 60S. LOWS SATURDAY NIGHT IN THE TEENS WITH MID 20S (EAST) TO
LOW/MID 30S FAR WEST SUNDAY.
SUNDAY NIGHT-THURSDAY...FORECAST AREA REMAINS UNDER NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. WEATHER SYSTEMS MOVE THROUGH THE FLOW
SUNDAY NIGHT THEN AGAIN MONDAY NIGHT AND TUESDAY NIGHT.
HOWEVER...DOESNT LOOK LIKE ANY OF THESE PRODUCE ANY PRECIPITATION.
TEMPERATURES SLOWLY WARM MONDAY AND TUESDAY BEFORE COOLING DOWN
WEDNESDAY AND THEN WARMING UP AGAIN THURSDAY.
LOWS SUNDAY NIGHT IN THE TEENS WITH LOW TO MID 20S MONDAY
NIGHT-WEDNESDAY NIGHT. HIGHS MONDAY LOW TO MID 40S ALTHOUGH
GFS/ECMWF 850 TEMPS SUPPORT READINGS A BIT HIGHER. FOR TUESDAY LOW
TO MID 40S EAST WITH UPPER 40S TO LOW 50S WEST. ON WEDNESDAY AN
UNCERTAIN LOW TO MID 40S AS DIFFERENCES SHOW UP IN JUST HOW MUCH
COOLER IT WILL BE WITH LARGE DISPARITY BETWEEN ECMWF/GFS 850
TEMPERATURES. FOR THURSDAY GENERALLY MID TO UPPER 40S...ECMWF
SUGGESTS IT WILL BE WARMER THEN CURRENT FORECAST PER 850
TEMPERATURES WHILE GFS ABOUT 5C COOLER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 425 PM MST THU DEC 26 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE WIND WILL
GRADUALLY BACK FROM NORTHWESTERLY TO WESTERLY THIS EVENING BUT
REMAIN LESS THAN 10 KNOTS. A WESTERLY/SOUTHWESTERLY WIND WILL
CONTINUE TOMORROW AND MAY INCREASE TO BETWEEN 10 AND 12 KNOTS
DURING THE AFTERNOON...ESPECIALLY AT GLD. FEW TO OCCASIONALLY
SCATTERED HIGH CLOUDS WILL OCCUR THROUGH THE END OF THE TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
258 PM EST WED DEC 25 2013
.SYNOPSIS...
AFTER A ROUND OF SNOW OVERNIGHT INTO THURSDAY...CONDITIONS SHOULD BE
DRY UNTIL ANOTHER COLD FRONT COMES THROUGH SUNDAY AND MONDAY.
TEMPERATURES WILL RISE TO ABOVE NORMAL VALUES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
CLOUD SHIELD CONTINUES TO ADVANCE FROM THE WEST THIS
AFTERNOON...SLOWLY OVERRUNNING THE ENTIRE FORECAST AREA. WHILE THE
PREVIOUS FORECAST ANTICIPATED A ROUND OF SNOW LATE TONIGHT INTO
THURSDAY MORNING WITH AN UPPER LEVEL TROUGH...LATEST HIGH-RESOLUTION
MODEL RUNS ARE INDICATING THAT A SECOND ROUND OF SNOW WILL OCCUR
BEFORE THE TROUGH PASSAGE. WHILE THE TROUGH REMAINS OVER MICHIGAN
DURING THE EVENING HOURS...AN UPPER LEVEL SHORTWAVE WILL MOVE IN
FROM THE SOUTHWEST. IN ADDITION...MULTIPLE RUNS OF THE RAP SHOW
FRONTOGENESIS DEVELOPING AT 850MB...AND TO A LESSER EXTENT IN THE
12Z NAM. SEVERAL HIRES MODELS SHOW A BAND OF SNOW DEVELOPING ALONG
THE FRONTOGENESIS BY LATE EVENING ACROSS SOUTHERN OHIO EXTENDING
INTO NORTHWESTERN PENNSYLVANIA. THIS BAND SHOULD SLOWLY MOVE TO THE
EAST DURING THE OVERNIGHT HOURS. OVERNIGHT SNOWFALL TOTALS COULD
REACH AN INCH...WITH ISOLATED TWO INCH AMOUNTS POSSIBLE.
LITTLE CHANGE HAS BEEN MADE TO THE PORTION OF THE FORECAST WITH THE
PASSAGE OF THE UPPER TROUGH. TIMING AND ACCUMULATIONS APPEAR TO BE
SIMILAR TO THAT OF THURSDAY MORNING...WITH GENERAL TOTALS AROUND AN
INCH WITH ANOTHER CHANCE FOR ISOLATED TWO INCH AMOUNTS.
HOWEVER...12Z MODELS HAVE INCLUDED SLIGHT REDUCTIONS IN SNOWFALL
TOTALS. BULK OF PRECIPITATION SHOULD HAVE MOVED EAST OF THE REGION
BY NOON...ALTHOUGH THE TYPICAL UPSLOPE/LAKE EFFECT AREAS SHOULD
EXPECT SCATTERED SNOW SHOWERS TO CONTINUE INTO THE AFTERNOON.
TEMPERATURES SHOULD BE MILD OVERNIGHT...WITH HIGHS A FEW DEGREES
BELOW NORMAL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
MINIMAL CHANGE WAS NEEDED IN THE SHORT TERM AS MODELS SHOW FAIRLY
DECENT CONTINUITY WITH PREVIOUS RUNS. HIGH PRESSURE WILL BEGIN TO
BUILD IN THURSDAY NIGHT FROM THE SOUTH AND WILL MARK THE BEGINNING
OF A RELATIVELY DRY PERIOD FOR THE FORECAST AREA. WINDS WILL
BECOME WEST SOUTHWEST AS HIGH PRESSURE SHIFTS TO THE SOUTH. THIS
WILL RESULT IN TEMPERATURES WARMING TO SLIGHTLY ABOVE NORMAL AND
CONTINUED DRY CONDITIONS. BASED ON LATEST SOUNDINGS...WE MAY
ACTUALLY SEE A FAIR AMOUNT OF SUNSHINE ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A QUICK WARM UP WILL ENSUE SUNDAY AHEAD OF A FAIRLY STRONG COLD
FRONT. SYSTEM WILL BE MOISTURE STARVED FOR THE MOST PART AND
SCATTERED RAIN AND SNOW SHOWERS LATE DAY SUNDAY WILL CHANGE TO ALL
SNOW SHOWERS FOR SUNDAY NIGHT AS MUCH COLDER AIR ONCE AGAIN SURGES
SOUTH ACROSS THE REGION. EXTENDED CHC POPS FOR SNOW SHOWERS INTO
MONDAY NIGHT ESPECIALLY FOR THE RIDGES. NEXT CLIPPER THEN FLIES
SOUTHEAST IN NORTHWEST FLOW ALOFT FOR TUESDAY...AND THIS IS ANOTHER
SYSTEM THAT WILL HAVE LITTLE MOISTURE TO WORK WITH AND SLGT CHC
POPS CONTINUED. BY MID WEEK SURFACE RIDGE WILL BRING DRY AND COLD
CONDITIONS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
BREAKS IN THE VFR MID DECK WILL FILL IN BY EARLY EVENING. BAND OF
SNOW WILL DEVELOP OVER SOUTHERN OHIO LATE THIS EVENING AND EXTEND
NORTHEAST INTO NORTHWEST PENNSYLVANIA. CURRENT MVFR VISIBILITIES IN
TAFS WITH THIS BAND MAY BE TOO OPTIMISTIC...WITH IFR VISIBILITIES
CERTAINLY POSSIBLE. AT THIS POINT...IFR VIS WAS HELD OFF IN TAFS
UNTIL A SECOND ROUND OF SNOW ARRIVES WITH AN UPPER LEVEL TROUGH
AROUND SUNRISE ON THURSDAY. SNOW IS EXPECTED TO BE LIGHTER AT
ZZV/MGW AND HAVE ONLY GONE WITH MVFR/VFR VIS AT THOSE TERMINALS.
BY EARLY THURSDAY AFTERNOON MVFR CIGS WILL BE HOLDING ON AT MOST
SITES IN FLURRIES...ALTHOUGH FKL/DUJ MAY CONTINUE TO KEEP IFR CIGS
THROUGH THE REST OF THE AFTERNOON.
.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
IMPROVEMENT TO VFR IS EXPECTED ONCE AGAIN THURSDAY NIGHT ALTHOUGH
MVFR CIGS MAY LINGER ACROSS THE NORTH. GENERAL VFR FRIDAY THROUGH
SATURDAY. AN APPROACHING COLD FRONT MAY BRING RESTRICTIONS ACROSS
THE NORTH LATE DAY SUNDAY AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1228 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS HERE WITH A W UPSLOPE FLOW
TO GIVE WAY TO A PERIOD OF LOWER LIFR CONDITIONS TNGT WITH THE
ARRIVAL OF A LO PRES TROF/WSHFT TO MORE WNW. ALTHOUGH CONDITIONS WL
IMPROVE LATER TNGT/THU MRNG FOLLOWING THE EXIT OF THIS TROF...IFR
VSBYS SHOULD PERSIST THRU 18Z THU WITH LK EFFECT -SHSN LINGERING.
IWD...EXPECT MVFR TO VFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF IFR VSBYS TNGT WITH THE APRCH/PASSAGE OF A LO PRES TROF.
FOLLOWING THE EXIT OF THIS TROF LATER TNGT...CONDITIONS WL IMPROVE
TO MVFR AND THEN TO VFR ON THU WITH THE APRCH OF A HI PRES RDG/
BACKING LLVL FLOW.
SAW...EXPECT VFR TO OCNL MVFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE. VFR
WX SHOULD THEN FOLLOW LATE TNGT INTO THU WITH A DOWNSLOPE W WIND
FOLLOWING THE TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE. HEAVY FREEZING SPRAY IS ALSO EXPECTED FROM SATURDAY NIGHT
INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR
MIZ006-007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1228 PM EST WED DEC 25 2013
.UPDATE...
ISSUED AT 1043 AM EST WED DEC 25 2013
CANX GOING WARNING FOR LUCE COUNTY EARLY GIVEN EXIT OF ENHANCED CLD
SHOWN ON IR STLT LOOP AND SHIFT OF HEAVY LES BAND TO THE E INTO
CHIPPEWA COUNTY PER CNDN MONTREAL RIVER RADAR. NEARBY SFC OBS ALSO
SHOW A WSHFT TO THE WSW AT ERY AND NAUBINWAY...CONSISTENT WITH THE
PASSAGE OF THE HEAVIER BAND TO THE E. SOME SCT SHSN WL CONT THRU THE
DAY IN LUCE COUNTY...BUT ANY ADDITIONAL ACCUM SHOULD BE LESS THAN AN
INCH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1228 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS HERE WITH A W UPSLOPE FLOW
TO GIVE WAY TO A PERIOD OF LOWER LIFR CONDITIONS TNGT WITH THE
ARRIVAL OF A LO PRES TROF/WSHFT TO MORE WNW. ALTHOUGH CONDITIONS WL
IMPROVE LATER TNGT/THU MRNG FOLLOWING THE EXIT OF THIS TROF...IFR
VSBYS SHOULD PERSIST THRU 18Z THU WITH LK EFFECT -SHSN LINGERING.
IWD...EXPECT MVFR TO VFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF IFR VSBYS TNGT WITH THE APRCH/PASSAGE OF A LO PRES TROF.
FOLLOWING THE EXIT OF THIS TROF LATER TNGT...CONDITIONS WL IMPROVE
TO MVFR AND THEN TO VFR ON THU WITH THE APRCH OF A HI PRES RDG/
BACKING LLVL FLOW.
SAW...EXPECT VFR TO OCNL MVFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE. VFR
WX SHOULD THEN FOLLOW LATE TNGT INTO THU WITH A DOWNSLOPE W WIND
FOLLOWING THE TROF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...KC
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1044 AM EST WED DEC 25 2013
.UPDATE...
ISSUED AT 1043 AM EST WED DEC 25 2013
CANX GOING WARNING FOR LUCE COUNTY EARLY GIVEN EXIT OF ENHANCED CLD
SHOWN ON IR STLT LOOP AND SHIFT OF HEAVY LES BAND TO THE E INTO
CHIPPEWA COUNTY PER CNDN MONTREAL RIVER RADAR. NEARBY SFC OBS ALSO
SHOW A WSHFT TO THE WSW AT ERY AND NAUBINWAY...CONSISTENT WITH THE
PASSAGE OF THE HEAVIER BAND TO THE E. SOME SCT SHSN WL CONT THRU THE
DAY IN LUCE COUNTY...BUT ANY ADDITIONAL ACCUM SHOULD BE LESS THAN AN
INCH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 646 AM EST WED DEC 25 2013
LGT SNOW AND FLURRIES CONTINUE INTO EARLY AFTN AS A LOW PRESSURE
TROUGH SLOWLY CROSSES THE AREA. EXPECT MVFR CONDITIONS WITH THE SNOW
BOTH FM CIGS AND VSBY. AS WINDS TURN TO THE NORTHWEST LATER TODAY
INTO TONIGHT IN WAKE OF THE LOW...LAKE EFFECT SNOW SHOWERS WITH IFR
CONDITIONS WILL DEVELOP AT IWD AND CMX. POTENTIAL FOR HEAVIER BAND
OF SNOW TO PRODUCE LIFR CONDITIONS AT CMX...BUT NOT ENOUGH CONFIDENCE
ON EXACT LOCATION TO INCLUDE AT THIS TIME. SOME MORE LGT SNOW OR
FLURRIES MAY OCCUR TONIGHT AT SAW AS AN UPPER DISTURBANCE MOVES JUST
SOUTH OF THE AREA...THOUGH AFTER THIS SYSTEM MOVES BY CLOUDS MAY TRY
TO SCATTER OUT LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
648 AM EST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 646 AM EST WED DEC 25 2013
LGT SNOW AND FLURRIES CONTINUE INTO EARLY AFTN AS A LOW PRESSURE
TROUGH SLOWLY CROSSES THE AREA. EXPECT MVFR CONDITIONS WITH THE SNOW
BOTH FM CIGS AND VSBY. AS WINDS TURN TO THE NORTHWEST LATER TODAY
INTO TONIGHT IN WAKE OF THE LOW...LAKE EFFECT SNOW SHOWERS WITH IFR
CONDITIONS WILL DEVELOP AT IWD AND CMX. POTENTIAL FOR HEAVIER BAND
OF SNOW TO PRODUCE LIFR CONDITIONS AT CMX...BUT NOT ENOUGH CONFIDENCE
ON EXACT LOCATION TO INCLUDE AT THIS TIME. SOME MORE LGT SNOW OR
FLURRIES MAY OCCUR TONIGHT AT SAW AS AN UPPER DISTURBANCE MOVES JUST
SOUTH OF THE AREA...THOUGH AFTER THIS SYSTEM MOVES BY CLOUDS MAY TRY
TO SCATTER OUT LATE TONIGHT. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM EST WED DEC 25 2013
IFR CONDITIONS WITH LIGHT SNOW WILL CONTINUE EARLY THIS FORECAST
PERIOD AS A TROF MOVES ACROSS THE AREA. AS THE SN DIMINISHES W-E BY
SUNRISE ON WED...MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS
TOWARD THE W LATER ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX
BY EARLY WED EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...07
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1201 AM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS SHRTWV RDG AXIS
MOVING INTO THE WRN LKS BTWN DEPARTING TROF IN THE SE GRT LKS
RESPONSIBLE FOR LES THE PAST FEW DAYS AND A PAIR OF SHRTWVS DIGGING
SEWD THRU SCENTRAL CANADA/THE NRN ROCKIES E OF MEAN RDG NEAR THE W
COAST. WITH SFC HI PRES BLDG ACRS THE AREA...LINGERING LES NEAR LK
SUP HAS DIMINISHED AND PUSHED INTO THE OPEN WATERS AS THE FLOW IS
SHIFTING TO THE SSW IN ADVANCE OF THE SFC LO PRES TROF IN THE NRN
PLAINS ASSOCIATED WITH THE TWO CLIPPER SHRTWVS. THE 12Z INL/MPX
RAOBS SHOWED A VERY DRY AIRMASS WITH PWATS UNDER 0.10 INCH...SO
SKIES ARE TURNING MOSUNNY AT MOST PLACES AS THE SSW FLOW SHIFTS
LINGERING LO CLDS BACK OUT OVER LK SUP. MID CLDS IN ADVANCE OF
APRCHG CLIPPER SHRTWVS/SFC TROF ARE PUSHING EWD THRU MN...WITH SN
FALLING OVER NW MN AND THE ERN DAKOTAS. ALTHOUGH THIS SN HAS BEEN
MDT AT SOME PLACES UNDER THE SHARPER H85-5 QVECTOR CVNGC...THE
COVERAGE APPEARS TO BE LIMITED BY ABSENCE OF SGNFT MSTR INFLOW.
MAIN FCST CONCERNS IN THE SHORT TERM ARE EXPECTED POPS/SN AMOUNTS
LATE TNGT AND XMAS MRNG ASSOCIATED WITH UPSTREAM CLIPPER SHRTWVS AND
GOING WINTER STORM WATCH OVER THE ERN CWA/NEED FOR ANY NEW HEADLINES.
TNGT INTO XMAS DAY...UPR TROF TO THE NW IS FCST TO SHIFT TO THE SE
AND STRETCH FM NW ONTARIO THRU MN AND INTO THE CENTRAL PLAINS BY 12Z
WED. MODELS SHOW PCPN IN ADVANCE OF THIS TROF ARRIVING OVER THE WRN
CWA LATE THIS EVNG AND PUSHING TO THE E...WITH A 6-9 PERIOD OF SN AT
MOST LOCATIONS BEFORE THE SN DIMINISHES OVER THE W 09-12Z WED AND BY
ABOUT 18Z WED OVER THE ERN CWA FOLLOWING DEPARTURE OF DEEP LYR
QVECTOR CNVGC. MAIN NEGATIVES FOR SGNFT SN FALL INCLUDE FCST SHARPER
H85-5 QVECTOR CNVGC/SHARPER H7 UVV ASSOCIATED WITH INCOMING OUT OF
PHASE SHRTWVS FOCUSING TO THE S OF UPR MI... LACK OF SGNFT MSTR
INFLOW WITH ONLY ABOUT 1.5-2 G/KG SPECIFIC HUMIDITY NEAR H7...AND
LIMITED RESIDENCE OF TIME OF PCPN. ONE FACTOR IN FAVOR OF SOMEWHAT
HIER SN AMOUNTS IS FCST DEEP DGZ THAT MAY BOOST SN/WATER RATIOS AS
HI AS 20-25:1. CONSIDERING MODEL QPF 0.05-0.15 INCH...EXPECT 1 TO 3
INCHES OF SN. THE ONE EXCEPTION WL BE OVER THE ERN CWA DOWNWIND OF
LK MI...WHERE INCRSG SSW FLOW UP THE LENGTH OF LK MI IN THE PRESENCE
OF DEEP MSTR/H85 TEMPS ARND -15C WL BRING A PERIOD OF HEAVIER LK
ENHANCED SN. PRESENCE OF LINGERING BAND IN NRN LK MI AS SHOWN ON
RECENT STLT IMAGERY EARLY THIS AFTN INCREASES CONFIDENCE IN THIS
FCST. BULK OF HIER RES MODELS SHOW THE HEAVIER LES BAND IMPACTING
FAR SE SCHOOLCRAFT COUNTY/SRN LUCE COUNTY IN THE 09Z-15Z WED TIME
FRAME. WITH MODEL QPF RANGING FM 0.25 INCH TO AS MUCH AS 0.40 INCH
AND DEEP DGZ SHOWN ON THE FCST SDNGS...EXPECT AT LEAST A HI END ADVY
SNFALL IN THIS AREA. FCST SDNGS ALSO SHOW A PERIOD OF NEARLY
UNIDIRECTIONAL SSW FLOW WITHIN THE MIXED LYR FOR A FEW HRS DURING
TIME OF PEAK SN INTENSITY. GIVEN THESE FVRBL CONDITIONS...OPTED TO
UPGRADE WATCH TO A WRNG FOR LUCE COUNTY...WHERE HEAVIER LES BAND IS
MOST LIKELY TO RESIDE THE LONGEST AND DROP UP TO 9 TO PERHAPS 10
INCHES ALONG M-28 E OF ERY. WENT WITH AN ADVY FOR SCHOOLCRAFT COUNTY
WITH POTENTIAL FOR SOME LK ENHANCEMENT...ESPECIALLY E OF SENEY AND
MANISTIQUE. AS FOR TEMPS...ARRIVAL OF THICKER CLDS/STEADY S WIND WL
ALLOW FOR ONLY A RELATIVELY SMALL TEMP DIP EARLY OVER THE W HALF.
BUT TO THE E...EXPECT TEMPS TO FALL QUICKLY OVER THE INTERIOR ERN
CWA THIS EVNG BEFORE THE CLDS AND STEADY S WINDS ARRIVE LATER.
LATER ON XMAS DAY...AS THE UPR TROF AND SFC REFLECTION SHIFT SLOWLY
THRU THE UPR GREAT LKS...THE LLVL FLOW IS PROGGED TO VEER TOWARD THE
W. THIS WSHFT TO A MORE WSW DIRECTION WL END THE THREAT OF LK
ENHANCED SHSN OVER THE E BY EARLY AFTN BUT CAUSE SOME LES TO DVLP
OVER THE W IN THE AFTN AS H85 TEMPS DIP BACK NEAR -18C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
WEDNESDAY NIGHT...LOW LEVEL CONV ALONG A COLD FRONT AND 850
MB TEMPS DROPPING FROM -15C TO -19C WILL BRING AN INCREASE IN LES
INTO NORTHWEST UPPER MICHIGAN WED EVENING AND OVER ERN CWA
OVERNIGHT. EVEN WITH A FAVORABLE PLACEMENT OF THE DGZ IN THE
CONVECTIVE LAYER GIVING SLR VALUES NEAR 25/1...INVERSION HEIGHTS
NEAR 6K FT AND STEADILY VEERING WINDS SHOULD KEEP ACCUMULATIONS IN
THE 2 TO 4 INCH RANGE...WITH THE GREATEST AMOUNTS IN THE HIGHER
TERRAIN FROM CALUMET TO TWIN LAKES AND NORTH OF M-28 EAST OF
MUNISING.
THU INTO THU NIGHT...NW FLOW LES WILL GRADUALLY DIMINISH AS A WEAK
SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES
BRINGING BACKING WINDS AND LOWERING INVERSION HEIGHTS. THE STRONGEST
FORCING AND MOST FAVORABLE WAA/ISENTROPIC LIFT ASSOCIATED WITH A
WEAK CLIPPER SHORTWAVE TROUGH IS EXPECTED TO REMAIN SOUTH OF THE
UPPER MICHIGAN.
FRI...THE ECMWF WAS MORE AGGRESSIVE WITH POTENTIAL FOR SOME LIGHT
SNOW BY LATE FRI WITH THE WAA/ISENTROPIC LIFT PATTERN DEVELOPING
AHEAD OF THE NEXT CLIPPER SHRTWV AND SFC LOW MOVING TOWARD NW
ONTARIO COMPARED TO THE GFS/GEM. WITH LOW CONFIDENCE IN ANY
PCPN...ONLY SLIGHT/CHANCE POPS WERE INCLUDED...MAINLY OVER THE EAST.
SAT INTO SAT NIGHT...A BRIEF WARMUP IS EXPECTED SATURDAY AS UPPER MI
WILL BE IN THE WARMER SECTOR AHEAD OF THE NEXT LOW. TEMPS SHOULD
CLIMB ABOVE NORMAL WITH HIGHS AROUND 30. MODEL DIFFERENCES WERE EVEN
GREATER BY SATURDAY NIGHT...AS THE ECMWF WAS SLOWER/DEEPER WITH
SHRTWV AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. REGARDLESS OF
MODEL DIFFERENCES...A COLD FRONT MOVING THROUGH WITH WINDS VEERING
SHARPLY TO THE NNW SHOULD BRING LES OR LAKE ENHANCED SNOW INTO NRN
UPPER SAT NIGHT.
SUN-TUE...ANOTHER VERY COLD ARCTIC AIRMASS WILL DOMINATE THE REGION
THROUGH THE PERIOD WITH LES EXPECTED FOR NW WIND FAVORED SNOWBELTS.
WIND CHILL VALUES NEAR ADVISORY WILL BE POSSIBLE OVER THE WEST HALF
BOTH EARLY MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM EST WED DEC 25 2013
IFR CONDITIONS WITH LIGHT SNOW WILL CONTINUE EARLY THIS FORECAST
PERIOD AS A TROF MOVES ACROSS THE AREA. AS THE SN DIMINISHES W-E BY
SUNRISE ON WED...MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS
TOWARD THE W LATER ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX
BY EARLY WED EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT TIGHTENS OVER LAKE SUPERIOR THIS EVENING
BETWEEN DEPARTING SURFACE HI PRES RIDGE AND AN APPROACHING LO PRES
TROF...OPTED TO MAINTAIN GOING GALE WARNING FOR THE ECENTRAL
PORTIONS OF THE LAKE. AWAY FROM THIS FAVORED AREA...SOME GALE FORCE
GUSTS WILL BE POSSIBLE. CLOSER APPROACH AND THEN PASSAGE OF LO PRES
TROF AND WEAKER GRADIENT ON WED WILL CAUSE THE GALES TO DIMINISH AS
THE WINDS VEER TOWARD THE W-NW. NORTHWEST TO NORTH GALES WILL AGAIN
BE POSSIBLE SATURDAY NIGHT BEHIND AN ARCTIC COLD FRONT. HEAVY
FREEZING SPRAY IS ALSO EXPECTED INTO EARLY NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1229 PM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1220 PM CST WED DEC 25 2013
CONDITIONS ARE LARGELY IMPROVING ACROSS THE AREA WITH STEADY SNOW
PUSHING EAST THROUGH WISCONSIN. GUSTY WINDS BEHIND A COLD FRONT
HAS LED TO SOME BLOWING SNOW ACROSS WESTERN MN...WITH VSBYS IN THE
MVFR CATEGORY. OTHERWISE...MVFR/VFR CIGS EXPECTED THROUGH TONIGHT.
ANOTHER BATCH OF SNOW WILL SLIDE SOUTHEAST...MAINLY ALONG AND JUST
NORTH OF THE MINNESOTA RIVER LATE THURSDAY MORNING.
KMSP...MVFR CONDITIONS WILL BECOME MAINLY VFR THIS
AFTERNOON...THEN BACK TO MVFR LATE THURSDAY MORNING WITH THE NEXT
ROUND OF SNOW.
/OUTLOOK FOR KMSP/
THU NIGHT...VFR. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ041-
042-047>049-054>057-064-065-073>075-082-083-091-092.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
608 AM CST WED DEC 25 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 540 AM CST WED DEC 25 2013
THE COMBINATION OF CYCLONIC FLOW AND A WARM FRONT LAYING OUT
ACROSS THE AREA THIS TAF PERIOD WILL RESULT IN PLENTY OF CLOUD
COVER WITH NUMEROUS BOUTS OF LIGHT SNOW. MOST CONFIDENCE ON THE
SNOW EXISTS WITH BURST CURRENTLY WORKING ACROSS THE AREA. HAVE
CONTINUED TO FOLLOW THE HRRR TO TREND THIS SNOW THROUGH THE
TERMINALS. EXPECT IFR VSBY SNOW TO REMAIN SOUTH OF ALL TERMINALS
BUT RWF...WITH THE REST JUST DEALING WITH 2 TO 4 HOURS OF
INTERMITTENT MVFR SNOWS THIS MORNING. AFTER THAT...SREF PROBS AND
HIGH-RES MODELS SHOW A RATHER CHAOTIC SNOW PICTURE PLAYING OUT
THROUGH TONIGHT. GIVEN THE LOW CONFIDENCE ON WHEN/WHERE FUTURE
BANDS OF SNOW WILL EXIST...LEFT ANY SNOW MENTION BEYOND THIS
MORNING OUT...THOUGH IN ALL LIKELIHOOD MORE MVFR TYPE SNOWS WILL
BE SEEN FROM TIME TO TIME BEYOND THIS MORNING. CIGS WILL MOSTLY
STAY MVFR THROUGH THE MORNING...BUT AS A COLD FRONT SLOWLY SLIDES
SOUTH THROUGH THE AREA THIS AFTERNOON/EVENING WILL LIKELY SEE SOME
BREAKS IN THE CLOUDS...THOUGH CLOUD COVER WILL DOMINATE THE SCENE.
LOW CONFIDENCE BEYOND THIS AFTERNOON WITH CIG HEIGHTS...SO WENT
CONSERVATIVE WITH CIGS BECOMING VFR THIS EVENING...THOUGH WE WILL
PROBABLY SEE MVFR OR LOWER CIGS AT TIMES RIGHT THROUGH THE END OF
THE PERIOD. WINDS WILL BE STRONGEST THIS MORNING/EARLY AFTERNOON
AHEAD OF THE COLD FRONT OVER SW MN...WILL LIKELY SEE SOME
BLSN...THOUGH HARD TO SAY IF IT WILL LEAD TO VIS RESTRICTIONS AT
RWF...BUT LEFT THAT IDEA IN FROM THE PREVIOUS TAF.
KMSP...BASED ON RADAR...LOOKING LIKE HEAVIEST SNOW WILL GO SOUTH
AND NORTH OF THE FIELD...THOUGH A PERIOD OF MVFR VSBYS STILL LOOKS
LIKELY THIS MORNING. WILL LIKELY BE MORE SNOW AFTER THIS
MORNING...BUT CONFIDENCE TOO LOW ON WHEN ADDITIONAL SNOW SHOWERS
WILL OCCUR TO INCLUDE IN THE TAF AT THIS TIME. BASED ON UPSTREAM
OBS...CIGS CURRENTLY ABOVE 017 LOOK TO BE SHORT LIVED...WITH CIGS
MAINLY 012-015 NW OF MSP. CONFIDENCE IN CIG FORECAST THIS
AFTERNOON ON IS LOW. WINDS LOOK TO GO NORTH OF 240 BETWEEN 16Z AND
18Z...SO WILL EVENTUALLY HAVE TO GET EVERYTHING OVER TO THE 30S
THIS AFTERNOON.
/OUTLOOK FOR KMSP/
THU...CHANCE MVFR CIGS/VSBYS IN -SN. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
338 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1137 PM CST TUE DEC 24 2013
MVFR CONDITIONS FOR MUCH OF THE OVERNIGHT AND CHRISTMAS
DAY...EXCEPT TOWARD AXN WHERE IFR WILL PREVAIL. GUIDANCE IS VERY
PESSIMISTIC WITH CIGS AND VSBYS OVERNIGHT...PROBABLY DUE TO THE
RESIDUAL EFFECTS OF HEAVY SNOW THIS EVENING. DO NOT BELIEVE ATTM
DENSE FOG OR LIFR CIGS ARE IN THE CARDS. ANOTHER BATCH OF SNOW
WILL SLIDE SOUTHEAST ACROSS MN LATE TONIGHT AND CHRISTMAS MORNING
WITH A 2-3 HOUR WINDOW OF 2-4SM -SN. FOLLOWING THAT...GUSTY
NORTHWEST WINDS WILL BRING A GOOD CHANCE OF BLOWING SNOW TO
WESTERN MN.
KMSP...CIGS WILL TEETER BETWEEN 015 AND 020 FOR MUCH OF THE
OVERNIGHT...WITH SUB 015 CIGS LIKELY ACCOMPANYING THE NEXT ROUND
OF SNOW EARLY WEDNESDAY. IMPROVING CONDITIONS THEREAFTER.
/OUTLOOK FOR KMSP/
THU...VFR. CHANCE MVFR CIGS/VSBYS IN -SN. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BECOMING NW
20G30 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1159 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1147 AM CST WED DEC 25 2013
CLEAR TO MOSTLY CLEAR SKIES CAN BE EXPECTED THROUGH TONIGHT WITH
PERHAPS INCREASING MID TO HIGH CLOUDS THURSDAY MORNING.
HOWEVER...WILL NEED TO KEEP AN EYE ON A SCATTERED DECK OF MVFR
CLOUDS WILL PASS JUST TO THE NORTHEAST OF KGRI THIS AFTERNOON. THE
WIND WILL BE GUSTY AT TIMES THIS AFTERNOON...BUT WILL QUICKLY DIE
OFF THIS EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
542 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z THURSDAY MORNING)
ISSUED AT 542 AM CST WED DEC 25 2013
CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGHOUT THE
PERIOD...WITH ONLY LIMITED AMOUNTS OF PASSING MID/HIGH CLOUD
COVER...AND ANY DAYTIME BATCHES OF LOWER MVFR HEIGHT STRATUS
LIKELY TO REMAIN AT LEAST 60-80 MILES NORTHEAST OF KGRI. AS FOR
SURFACE WINDS...MADE VERY LITTLE CHANGE TO PREVIOUS
FORECAST...WITH BREEZES BOTH RIGHT AWAY EARLY THIS MORNING AND
AGAIN THIS EVENING/TONIGHT AVERAGING FROM A WESTERLY DIRECTION
NEAR/UNDER 10KT. HOWEVER...FOR SEVERAL HOURS TODAY ESPECIALLY
BETWEEN 17Z-20Z...NORTHWEST WINDS WILL INCREASE TO SUSTAINED
SPEEDS NEAR 16KT WITH GUST POTENTIAL TO AROUND 23KT...BEFORE
SUBSIDING LATE THIS AFTERNOON. PRIOR TO THE ONSET OF THE ENHANCED
BREEZES AT THE SURFACE...THERE WILL LIKELY BE AT LEAST A FEW HOURS
OF MODEST LOW LEVEL WIND SHEAR AS WINDS ACCELERATE INTO THE
40-45KT RANGE FROM THE NORTHWEST WITHIN THE LOWEST 1500 FT AGL.
GIVEN THAT THE WIND VECTOR MAGNITUDE DIFFERENCE BETWEEN THE
SURFACE AND THIS LEVEL IS FORECAST TO BE AT LEAST
35KT...INSERTED A FORMAL MENTION OF LLWS FROM 14Z-16Z THIS
MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
407 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1216 AM CST WED DEC 25 2013
CONFIDENCE IS HIGH IN VFR CEILING/VISIBILITY THROUGHOUT THE
PERIOD...WITH ONLY VERY LIMITED AMOUNTS OF MID/HIGH CLOUD
COVER...AND ANY BATCHES OF MVFR HEIGHT LOWER STRATUS EXPECTED TO
REMAIN AT LEAST 60-80 MILES NORTHEAST OF KGRI. THE MAIN
MODIFICATION FROM PREVIOUS TAF ISSUANCE WAS TO INCREASE SURFACE
WIND SPEEDS A BIT DURING THE DAYTIME HOURS. STARTING OFF EARLY
THIS MORNING...AND THEN AGAIN LATER IN THE PERIOD THIS EVENING...A
GENERALLY WESTERLY BREEZE IN THE 6-9KT RANGE WILL PREVAIL.
HOWEVER...FOR SEVERAL HOURS DURING THE DAY...ESPECIALLY CENTERED
BETWEEN 17Z-20Z...NORTHWEST BREEZES WILL INCREASE TO SUSTAINED
LEVELS AROUND 14KT WITH GUST POTENTIAL TO AROUND 23KT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1022 PM EST THU DEC 26 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST OF THE LAKES OVERNIGHT WITH
LOCALIZED HEAVY ACCUMULATIONS EAST OF LAKE ONTARIO. A WEAK
DISTURBANCE MAY BRING A GENERAL LIGHT SNOW FRIDAY MORNING WITH LAKE
EFFECT SNOW SLOWLY TAPERING OFF EAST OF THE LAKES AS HIGH PRESSURE
EDGES NORTHWARD INTO THE REGION. A TEMPORARY WARMING TREND IS THEN
EXPECTED FOR THE WEEKEND BEFORE A SURGE OF ARCTIC AIR ARRIVES NEXT
WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
WESTERLY FLOW LAKE SNOWS WILL CONTINUE ACROSS THE TUG HILL PLATEAU
GIVEN THE FULL LAKE FETCH AND CLOSER LOCATION OF LEFT ENTRANCE
REGION OF UPPER JET. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR
WILL BE COMMON WITHIN THE HEART OF THE BAND. A LAKE SNOW WARNING
WILL BE MAINTAINED FOR THE TUG HILL REGION WITH SNOWFALL TOTALS
EXCEEDING A FOOT.
LAKE ERIE SNOWS HAVE DIMINISHED CONSIDERABLY THE PAST FEW HOURS.
LATEST HRRR AND LOCAL WRF SHOWING THIS DIMINISHING TREND NICELY.
THEREFORE HAVE CANCELED THE ADVISORY FOR THIS AREA. MESOSCALE
MODELS DO SUGGEST SOME REDEVELOPMENT OFF LAKE ERIE LATE TONIGHT
AND FRIDAY MORNING...BUT THIS WILL BE FOCUSED ON A SOUTHWEST FLOW
WITH A LAKE BAND LIKELY TO DEVELOP TOWARD THE SUBURBS SOUTH OF
BUFFALO WITH A SNOWBURST DURING THE EARLY MORNING COMMUTE...THEN
SLIPPING BACK TO THE SOUTH AND WEAKENING BY MID MORNING.
TEMPERATURES OVERNIGHT WILL FALL TO THE MID TEENS TO LOW 20S...
MODERATED FROM FALLING TOO FAR BY PARTIAL CLOUD COVER AND WESTERLY
WINDS BACKING TO SOUTH BY DAYBREAK. HIGH TEMPS ON FRIDAY WILL BE
IN THE UPPER 20S TO LOWER 30S...MILDER THAN HAVE BEEN THE PAST FEW
DAYS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
WHILE A DEEP POLAR VORTEX WILL REMAIN IN PLACE IN THE VCNTY OF
HUDSON BAY DURING THIS PERIOD...THE UPPER LEVEL FLOW ACROSS THE
GREAT LAKES WILL LARGELY BE ZONAL. THIS WILL TEMPORARILY BLOCK THE
SUPPLY OF VERY COLD AIR...WHILE EXPANSIVE SFC HIGH PRESSURE OVER
THE SOUTHEAST WILL CIRCULATE MILDER CONDITIONS NORTHWARDS ACROSS
OUR REGION. OTHERWISE...UNEVENTFUL WEATHER CAN BE EXPECTED UNTIL
LATER IN THE WEEKEND WHEN A COMPLEX STORM SYSTEM FEATURING A
COASTAL LOW WILL HAVE TO BE WATCHED.
UP UNTIL THAT TIME...THE SYNOPTIC PATTERN ACROSS OUR REGION WILL BE
SIMPLE AND STRAIGHTFORWARD. FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...A LARGE AREA OF HIGH PRESSURE WILL BE ROOTED ACROSS ALL OF
THE DEEP SOUTH WHILE AN ARCTIC FRONTAL BOUNDARY STRETCHING FROM
CENTRAL QUEBEC TO THE UPPER GREAT LAKES WILL SLOWLY SAG SOUTH
TOWARDS OUR REGION. THIS WILL ENCOURAGE MODERATELY STRONG WARM
ADVECTION ACROSS THE LOWER GREAT LAKES REGION SO THAT H85 TEMPS WILL
FLEETINGLY VISIT THE POSITIVE SIDE OF ZERO C. AFTERNOON HIGHS ON
SATURDAY SHOULD BE WITHIN A COUPLE DEGREES OF 40F...WHILE OVERNIGHT
LOWS WILL BE IN THE UPPER 20S AND LOWER 30S. MEANWHILE THE CLOSEST
PCPN DURING THIS 24 HOUR WINDOW WILL BE NORTH OF THE THOUSAND
ISLANDS.
THINGS WILL THEN BECOME MORE COMPLICATED ON SUNDAY.
A WAVE OVER LAKE MICHIGAN WILL LIFT NORTHEAST ALONG THE NEARLY
STALLED ARCTIC FRONTAL BOUNDARY AND TRANSFER SOME OF ITS ENERGY TO A
SOUTHERN STREAM LOW THAT WILL BE WORKING UP THE MID ATLANTIC COAST.
THIS WILL PLACE THE BULK OF OUR FORECAST AREA IN A `RIP OFF ZONE` OF
SORTS...BETWEEN THE TWO MAIN CENTERS OF SYNOPTIC FORCING. THIS WILL
INCLUDE A STRONG AREA OF JET INDUCED LIFT THAT WILL TRACK BY JUST TO
OUR SOUTHEAST. WHILE THERE COULD BE A LITTLE LIGHT SNOW AROUND...
MAINLY ACROSS THE SRN TIER AND PORTIONS OF THE FINGER LAKES...
ACCUMULATIONS SHOULD BE INSIGNIFICANT. TEMPERATURES MAY EVEN BE HIGH
ENOUGH TO MIX IN OR CHANGE THE PCPN TO A SHORT PERIOD OF LIGHT RAIN.
AS THE NRN BRANCH LOW MOVES BY AND COMPLETES ITS ENERGY TRANSFER TO
THE COAST SUNDAY EVENING...THE ARCTIC FRONT THAT IT USED AS A
PATHWAY WILL SURGE ACROSS OUR FORECAST AREA. THIS WILL PLUNGE OUR
TEMPERATURES BACK BELOW NORMAL VALUES...INTO THE TEENS FOR MANY
AREAS. THESE VALUES WILL BE ABOUT 15 DEG LOWER THAN THOSE FROM THE
PREVIOUS COUPLE NIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE NORTHERN HEMISPHERE WILL FEATURE ANOMALOUSLY STRONG RIDGING OVER
THE RUSSIAN ARCTIC AND A LARGE POLAR VORTEX ACROSS THE HUDSON BAY
WHICH WILL SET THE STAGE FOR A CROSS POLAR FLOW. THE COLDEST OF THE
AIR (H85 -40C) HOWEVER...WILL REMAIN LOCKED UP OVER FAR NORTHERN
ONTARIO AND QUEBEC. A LITTLE CLOSER TO HOME...THE DEEP FULL LATITUDE
TROUGH MENTIONED OVER EASTERN NORTH AMERICA WILL CAUSE SOME OF THE
ARCTIC AIR (-22C) TO SETTLE SOUTH ACROSS WESTERN AND NORTH CENTRAL
NY DURING THIS PERIOD.
A POTENT FRONTAL BOUNDARY WILL SURGE ACROSS OUR FORECAST AREA SUNDAY
NIGHT INTO THE EARLY MORNING HOURS ON MONDAY. THERE WILL ALSO BE
THE POTENTIAL FOR A BRIEF PERIOD OF HEAVY SNOWFALL ACCOMPANYING THE
FRONTAL PASSAGE. BEHIND THE ARCTIC FRONT...A FRIGGED AIR MASS WILL SPILL
IN ACROSS WESTERN AND NORTH CENTRAL NY (850H TEMPS FALLING FROM -4C
TO -20 BY MONDAY NIGHT)WITH SOME MEASURE OF LAKE EFFECT SNOWS. THE
LARGE POLAR VORTEX OVER HUDSON BAY WILL SLOWLY DRIFT EASTWARD MONDAY
NIGHT INTO TUESDAY...AS IT DOES A WEAK CLIPPER TYPE SYSTEM WILL MOVE
THROUGH THE BASE OF THE TROUGH. THIS SYSTEM WILL BRING A CHANCE FOR
SOME MORE LIGHT SNOWS DURING THE DAY ON TUESDAY. FOLLOWING ITS
PASSAGE...A RE-ENFORCING SHOT OF COLD AIR WILL FILTER IN ACROSS THE
REGION (85H BACK TO -21C) AND ANOTHER ROUND OF LAKE EFFECT SNOWS
WILL DEVELOP OFF OF BOTH LAKE ERIE AND ONTARIO.
THE ECMWF/GFS SUGGEST THAT A WEAK SURFACE HIGH WILL BUILD SLOWLY
INTO THE REGION LATE WEDNESDAY. MEANWHILE ANOTHER CLIPPER TYPE STORM
SYSTEM MAY BE CROSSING THE UPPER GREAT LAKES. ALTHOUGH...AT THIS
POINT SLIGHT DIFFERENCES ARISE WHETHER THURSDAY WILL BE A RATHER
QUIET WX DAY OR THERE WILL BE SOME MORE LIGHT SNOW FROM THIS
CLIPPER SYSTEM MOVING ACROSS THE GREAT LAKES. ONE THING IS FOR
SURE...TEMPERATURES DURING THIS PERIOD WILL DEFINITELY BE BELOW
AVERAGE.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
THE MAIN IMPACT ON AVIATION THROUGH TONIGHT WILL BE LAKE EFFECT
SNOWS EAST OF THE LAKES WITH AREAS OF IFR VSBY AFFECTING MAINLY KJHW
AND KART...ESPECIALLY BETWEEN 06Z AND 12Z. THERE MAY BE A NORTHWARD
MOTION TO BRING IFR VSBY TO KBUF FROM 08Z TO 12Z.
OUTLOOK...
FRIDAY...MVFR/IFR IN LIGHT SNOW IMPROVING TO VFR IN THE AFTERNOON.
SATURDAY AND SUNDAY...MAINLY VFR.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. LOCAL
IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF THE LAKES.
&&
.MARINE...
MODERATE SOUTHERLY WINDS EARLY THIS MORNING WILL BECOME MORE
SOUTHWEST AND WEST TODAY WITH MODERATE WESTERLIES CONTINUING THROUGH
TONIGHT. THIS WILL PRODUCE ONGOING SMALL CRAFT ADVISORY CONDITIONS
ON BOTH LAKES THROUGH FRIDAY MORNING. A BRIEF DIMINISHING TREND IN
WINDS IS POSSIBLE FOR A FEW HOURS FRIDAY AFTERNOON BEFORE PICKING UP
AGAIN FRIDAY NIGHT THROUGH AT LEAST SATURDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST FRIDAY FOR NYZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LOZ042.
&&
$$
SYNOPSIS...TMA/WCH
NEAR TERM...TMA/WCH
SHORT TERM...RSH
LONG TERM...AR/RSH
AVIATION...TMA/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1128 PM CST TUE DEC 24 2013
.AVIATION...
4KM WRF AND HRRR SHOW STRATUS ADVECTING NORTH ON STRONG LLVL JET.
NAM/RAP SOUNDINGS ALSO INDICATE THIS ALTHOUGH GFS DOES NOT. SINCE
CLOUDS ARRIVE AT METROPLEX AFTER SUNRISE HAVE INDICATED A STRATUS
LAYER LIFTING TO VFR AFTER THE FROPA NEAR NOON. AT WACO SOUNDINGS
INDICATE A VERY SHALLOW IFR LAYER THAT WILL ALSO BURN OFF AFTER
SUNRISE. 84
&&
.UPDATE...
A COLD FRONT CONTINUES TO MOVE SOUTH THROUGH OKLAHOMA AND THE
TEXAS PANHANDLE THIS CHRISTMAS EVE. IMPRESSIVE PRESSURE RISES ON
THE ORDER OF 5 TO 6 MB ACROSS THE SOUTHERN FRONT RANGE. THE FRONT
SHOULD SURGE SOUTH THROUGH THE SOUTHERN HIGH PLAINS AND CHANGE
ORIENTATION A BIT...BUT STILL REACH THE NORTHWEST ZONES AROUND
SUNRISE.
SOME PATCHY FOG WILL BE POSSIBLE AHEAD OF THE FRONT...MAINLY
ACROSS THE WESTERN HALF OF NORTH TEXAS OVERNIGHT AND CHRISTMAS
MORNING. THE FOG WILL NOT BE AS DENSE AS IT WAS THIS MORNING AND
WE DO NOT ANTICIPATE ANY IMPACTS FROM FREEZING FOG.
THE CURRENT FORECAST IS IN GOOD SHAPE OVERALL SO WILL ONLY MAKE
SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDS.
79
&&
.PREV DISCUSSION... /ISSUED 249 PM CST TUE DEC 24 2013/
AFTER A FOGGY MORNING ACROSS THE NORTHWESTERN PORTIONS OF THE
FORECAST AREA...SKIES HAVE CLEARED WITH TEMPERATURES WARMING INTO
THE 40S AND 50S. SOUTHERLY WINDS HAVE RETURNED WHICH HAVE HELPED
WARM TEMPERATURES A FEW DEGREES VERSUS THIS TIME YESTERDAY. A
SHORTWAVE TROUGH IS CURRENTLY PUSHING INTO THE CENTRAL PLAINS AND
THIS TROUGH WILL SUPPORT ANOTHER FROPA FOR NORTH TEXAS TOMORROW.
AHEAD OF THE FRONT...SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT...
AND WITH LEFT OVER LOW-LEVEL MOISTURE ANOTHER ROUND OF FOG IS
POSSIBLE. DO NOT THINK VISIBILITIES WILL BE AS LOW AS THIS MORNING
DUE TO SLIGHTLY HIGHER WIND SPEEDS. WILL NOT MENTION FREEZING
FOG...AS LOWS IN THE NORTHWESTERN ZONES WILL BE CLOSER TO 30 AND
NOT IN THE UPPER 20S...SO CHANCES FOR IMPACTS WOULD BE LOWER AS
WELL. THE FOLLOWING SHIFTS MAY NEED TO ASSESS OR CHANGE THE
FORECAST IF DENSE FOG LOOKS MORE LIKELY OR TEMPERATURES BECOME
COLDER THAN FORECASTED.
THE FRONT IS EXPECTED TO PUSH INTO THE AREA LATE TOMORROW MORNING
AND AFTERNOON. STRONG VERTICAL MOTIONS WILL BE OCCURRING ACROSS
THE AREA AS THE TROUGH NEARS THE REGION OVERNIGHT AND
TOMORROW...BUT MOISTURE REMAINS SCOURED AS THE GULF OF MEXICO
REMAINS SHUT OFF. THEREFORE...NO RAIN IS EXPECTED WITH THIS FRONT.
THE FRONT WILL ACTUALLY HAVE LITTLE IMPACT TO OUR WEATHER. HIGHS
FRIDAY WILL BE INTO THE UPPER 50S WITH LOWER 60S BY SATURDAY
AFTERNOON.
ANOTHER PIECE OF ENERGY WILL MOVE INTO THE REGION FRIDAY...BUT NO
RAIN IS EXPECTED. WITH ONE FROPA AFTER ANOTHER...MOISTURE WILL
REMAIN TOO LOW TO SUPPORT PRECIPITATION. A LARGER TROUGH IS
EXPECTED TO DROP INTO THE CENTRAL AND EASTERN CONUS SATURDAY AND
SUNDAY. THIS TROUGH WILL SEND YET ANOTHER...AND STRONGER COLD
FRONT INTO THE FORECAST AREA SUNDAY. OVER THE PAST DAY OR TWO...WE
HAVE BEEN TALKING ABOUT THE CHANCES FOR LIGHT RAIN OR DRIZZLE IN
THE EASTERN ZONES WITH THE FROPA...BUT THIS SEEMS LESS LIKELY.
LATEST FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS OF
THE ATMOSPHERE WILL NOT OCCUR UNTIL AFTER FROPA AND WINDS WITHIN
THIS LAYER WILL ALREADY BE NORTHERLY BY THE TIME SATURATION
OCCURS. THIS WOULD SUPPORT DOWNWARD MOTIONS AND WOULD NOT LEAD TO
THE PRODUCTION OF PRECIPITATION. THIS FRONT WILL KEEP TEMPERATURES
COLDER THAN NORMAL...WITH FREEZES EXPECTED FOR MUCH OF THE AREA
MONDAY AND TUESDAY MORNING.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 32 52 32 54 34 / 0 0 0 0 0
WACO, TX 32 54 33 54 32 / 0 5 0 5 5
PARIS, TX 28 50 30 54 31 / 0 0 0 0 5
DENTON, TX 32 51 29 54 31 / 0 0 0 0 0
MCKINNEY, TX 29 51 30 54 31 / 0 0 0 0 0
DALLAS, TX 34 52 33 54 35 / 0 0 0 0 0
TERRELL, TX 31 53 31 54 31 / 0 0 0 0 5
CORSICANA, TX 32 56 33 54 33 / 0 5 0 5 5
TEMPLE, TX 32 55 34 55 33 / 0 5 0 5 5
MINERAL WELLS, TX 31 52 28 55 30 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
950 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 950 PM CST THU DEC 26 2013
SKY FORECAST IS EXTREMELY PROBLEMATIC...RESULTING FROM THE LARGE
CLEARING HOLE THAT HAS DEVELOPED IN CENTRAL MINNESOTA. OVERALL
THERE IS A GENERAL WESTERLY WIND FLOW...WHICH IS ALLOWING THE
CURRENT HIGHER BASED STRATUS OVER THE FORECAST AREA TO PUSH OFF TO
THE EAST. SO IT SEEMS THERE SHOULD BE CLEARING OVER THE NEXT FEW
HOURS BEHIND THIS HIGHER BASED STRATUS. MEANWHILE...THAT SAME
WESTERLY FLOW IS ALLOWING SOME ADVANCEMENT EASTWARD OF THE LOW
STRATUS IN WESTERN AND SOUTH CENTRAL MN. HOWEVER...THAT HOLE
THAT IS IN CENTRAL MINNESOTA IS EXPANDING. NAM/RAP LOW LEVEL RH
PROGS DO NOT HAVE A GOOD HANDLE ON THE SITUATION...BUT SPECIFIC
VALUES WOULD SEEM TO SUGGEST THAT THE STRATUS COMING AT US FROM
WESTERN MN WILL DISSIPATE SOME. AGAIN...NEEDLESS TO SAY A TOUGH
SKY FORECAST.
ON TOP OF THE SKY PROBLEM...IN THAT CLEARING HOLE VISIBILITIES
HAVE DROPPED IN SOME SPOTS TO 1/4 MILE. THIS COULD HAPPEN AS WELL
OVER THE FORECAST AREA WHEN SKIES CLEAR. HAVE INCLUDED PATCHY FOG
OVERNIGHT...BUT WOULD NOT BE SURPRISED IF THIS FOG NEEDS TO BE
EXPANDED IN COVERAGE. THERE IS EVEN AN OUTSIDE CHANCE OF A DENSE
FOG ADVISORY NEED IF SKIES CAN STAY CLEAR.
ON A FINAL NOTE...THE SNOW THAT BECAME ENHANCED A BIT ALONG I-94
IS DIMINISHING...RESULTING FROM A SHORTWAVE PASSAGE ON WATER VAPOR
AND ISENTROPIC DESCENT OCCURRING ON THE 270-275K SURFACES.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 528 PM CST THU DEC 26 2013
A WESTERLY FLOW RIGHT ABOVE THE GROUND THROUGH THE MID LEVELS OF
THE TROPOSPHERE WILL HELP TO CLEAR SKIES OUT AROUND 06Z. THIS
CLEARING COMBINED WITH AN INCREASE OF MOISTURE AT THE GROUND TODAY
BRINGS UP A CONCERN FOR FOG/MIST. A SOUTHWESTERLY BREEZE LOOKS TO
DEVELOP AT RST AT THE TIME OF CLEARING WHICH SHOULD HELP PREVENT
VISIBILITIES FROM DROPPING BELOW MVFR. HOWEVER...LSE COULD STAY
NEARLY CALM ALL NIGHT. AS SUCH...LOWER VISIBILITY CONCERN EXISTS
THERE. KEPT THE PREVIOUS FORECAST OF LOW MVFR VISIBILITIES...AT 3
SM...IN AGREEMENT WITH STATISTICAL GUIDANCE. HOWEVER...CANNOT RULE
OUT POTENTIAL FOR IFR VISIBILITIES. ANY FOG/MIST WILL DISSIPATE
AROUND 13Z AS MIXING FROM SUN COMBINES WITH THE WIND PICKING UP.
SOME ALTOSTRATUS LOOKS TO PASS ACROSS DURING THE DAY FRIDAY...BUT
CEILINGS WILL STAY VFR. MORE SIGNIFICANT IS THE AFOREMENTIONED
WINDS WHICH LOOK TO PICK UP TOWARDS 15-20 KT AT RST AND 10-15 KT
AT LSE. A STRONG WIND CORE IS ALSO SUGGESTED TO MOVE ACROSS THE
TAF SITES BETWEEN 19-23Z...BUT BASED ON SURFACE WINDS...LOW LEVEL
WIND SHEAR IS ONLY WARRANTED AT LSE AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
841 PM CST THU DEC 26 2013
.UPDATE...
PESKY SHORT WAVE STILL WORKING THROUGH THE AREA...KEEPING THE
LIGHT SNOW ALIVE THIS EVENING. IT SHOULD BEGIN TO DIMINISH
QUICKLY FROM NORTHWEST TO SOUTHEAST DURING THE REST OF THE EVENING.
SATELLITE IMAGERY SHOWS THE SHORT WAVE EXITING RAPIDLY WITH ENOUGH
SUBSIDENCE IN ITS WAKE THAT IT/S PUNCHING HOLES IN THE ALTOSTRATUS
ACROSS SOUTHERN MN. THIS MAKES FOR A TRICKY FORECAST WITH RESPECT
TO TEMPERATURES. THERE IS STILL PLENTY OF UNCERTAINTY AS TO HOW
MUCH CLEARING WILL OCCUR OVERNIGHT. THE NAM GENERALLY KEEPS THE
CLOUDS IN ALL NIGHT. REALITY SUGGESTS SOME CLEARING IN THE WAKE OF
THE SHORT WAVE. IF TEMPS FALL TOO FAST...WE COULD EVEN SEE SOME
FOG SINCE DEWPOINTS ARE STILL ELEVATED. HAVE MADE SOME MINOR
ADJUSTMENTS GIVEN LATEST TRENDS.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS SHOULD PREVAIL DURING THE TAF PERIOD. BKN-OVC
CLOUDS AT 5-7KFT SHOULD GRADUALLY CLEAR OVERNIGHT. THE LINGERING
LIGHT SNOW SHOULD ALSO END BY MIDNIGHT TONIGHT AS THE SHORT WAVE
PRODUCING IT SWINGS OFF TO THE EAST QUICKLY. THERE IS A LITTLE
CONCERN FOR SOME FOG TONIGHT IF TEMPS FALL TOO FAST UNDER ANY
CLEARING. DEWPOINTS REMAIN A ELEVATED AND A QUICK TEMP DROP WOULD
BRING RAPID SATURATION...LOW CONFIDENCE WITH THE FOG THREAT.
&&
.PREV DISCUSSION... /ISSUED 253 PM CST THU DEC 26 2013/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
UPSTREAM RADAR AND OBSERVATIONS SHOW LIGHT SNOW CONTINUING TO FALL
ACROSS SOUTHEAST MINNESOTA AND NORTHWEST WISCONSIN. WILL THUS
PROBABLY SEE A CHANCE FOR LIGHT SNOW CONTINUE INTO THE
EVENING...WINDING DOWN BY LATE EVENING AS THE SHORTWAVE FINALLY
BEGINS TO MAKE IT THROUGH THE AREA. NOT MUCH MORE THAN A DUSTING TO
A TENTH OF AN INCH OR TWO OF SNOW EXPECTED FROM HERE ON OUT.
ONCE AGAIN...CONCERNED ABOUT LOW TEMPS FOR TONIGHT...AS MODELS
DIFFERING QUITE A BIT WITH THE EXTENT OF CLOUD COVER. BASED ON
LATEST SATELLITE AND NAM/RAP LOW LEVEL MOISTURE...HAVE TRENDED
CLOUDIER FOR TONIGHT AND THUS TOWARD THE MILDER MODEL SOLUTIONS.
WITH VERY LIGHT WINDS EXPECTED THOUGH...TEMPS COULD DROP A FAIR
AMOUNT BELOW FORECAST VALUES IN SPOTS WHERE ANY CLEARING DOES OCCUR.
LOOKS LIKE A BRIEF BREAK IN TRENDS FOR TOMORROW...WITH NO
PRECIPITATION EXPECTED AND HIGH TEMPS NEAR TO EVEN A COUPLE DEGREES
ABOVE AVERAGE VALUES.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE...HIGH
THE 250 MB NORTHERN STREAM JET IS ACROSS THE U.S. CANADIAN BORDER
WITH A LARGE JET MAX MOVING ACROSS THE LAKE SUPERIOR AREA FRIDAY
NIGHT. WEAK UPPER DIVERGENCE BEGINS SATURDAY. 700 MB WARM
ADVECTION OCCURS FRIDAY NIGHT AND SATURDAY. 700 MB UPWARD MOTION
BEGINS SATURDAY. 700 MB RH DECREASES EARLY FRIDAY EVENING AND
BEGINS TO MOISTEN SATURDAY. 850 MB RH IS RATHER DRY. AND NO
PRECIPITATION IS EXPECTED. THERE SHOULD BE A STRONG LOW LEVEL
INVERSION SATURDAY...SO WINDS WILL NOT MIX DOWN MUCH.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE...HIGH
THE RIGHT ENTRANCE REGION OF THE 250 MB JET MAX IS OVER WISCONSIN
SATURDAY NIGHT AS THE BROAD UPPER TROUGH MOVES INTO THE UPPER
MISSISSIPPI VALLEY SUNDAY. THE WEAK UPPER DIVERGENCE CONTINUES
SATURDAY NIGHT AND INTO SUNDAY MORNING. 700 MB COLD AIR ADVECTION
BEGINS SATURDAY NIGHT AND CONTINUES SUNDAY. THE 700 MB UPWARD
MOTION CONTINUES SATURDAY NIGHT THEN BECOMES DOWNWARD ON SUNDAY.
THE 700 MB RH NEVER SATURATES SATURDAY NIGHT THEN DRIES ON
SUNDAY. 850 MB LAYERS SATURATE LATE SATURDAY NIGHT BUT DRIES
SATURDAY AFTERNOON. DUE TO DRY AIR BETWEEN 3 AND 12 THSD FT AND
MOIST LOW LEVELS...SOME FREEZING DRIZZLE IS POSSIBLE SATURDAY
NIGHT WITH TEMPERATURES STILL ABOVE FREEZING AT 5 THSD FT.
A SURFACE COLD FRONT MOVES ACROSS SOUTHERN WISCONSIN SATURDAY
NIGHT WITH BRISK NORTH WINDS SUNDAY WITH FALLING TEMPERATURES.
LIGHT POST FRONTAL PRECIPITATION SHOULD BRING A DUSTING OF LIGHT
SNOW SATURDAY NIGHT. THE INVERSION REMAINS BUT LIFTS...WITH THE
UNSTABLE LAYERS BELOW 3 THSD FT. FLURRIES EXPECTED SUNDAY DUE TO
MOIST AND RATHER UNSTABLE LOW LEVELS ON SUNDAY.
LONG TERM...
SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE...HIGH
THE 500 MB TROUGH AXIS MOVES ACROSS WISCONSIN WITH THE 00Z ECMWF
PUSHING TIT EAST QUICKER. STRONG COLD AIR ADVECTION CONTINUES
WITH 510 THICKNESS VALUES BY MONDAY MORNING. WIND CHILLS OF 20 TO
30 BELOW ZERO ARE LIKELY SUNDAY NIGHT INTO EARLY MONDAY.
THE 12Z GFS HAS HIGH PRESSURE OVER WISCONSIN MONDAY...WHILE THE
00Z ECMWF BRINGS SOME VERY LIGHT SNOW IN THE BAROCLINIC
ZONE...ESPECIALLY IN SOUTHWEST AREAS. THE GFS IS A LITTLE SLOWER
WITH THIS.
TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE...HIGH
A SECOND TROUGH DIGS INTO WISCONSIN...BUT THE BASE OF THE TROUGH
REMAINS OVER THE UPPER GREAT LAKES ON THE GFS. THE ECMWF IS A
LITTLE FASTER AND DEEPER. THEN THE FLOW IS MORE ZONAL ON THE ECMWF
WITH A LINGERING TROUGH OVER THE UPPER MISSISSIPPI VALLEY ON THE
GFS.
HIGH PRESSURE DOMINATES ACROSS THE GREAT LAKES TUESDAY AND
WEDNESDAY. WIND CHILLS OF 10 TO 20 BELOW ZERO ARE POSSIBLE
TUESDAY NIGHT INTO EARLY WEDNESDAY...BUT WINDS ARE LIGHTER ON THE
00Z ECMWF.
WARM AIR ADVECTION BEGINS THURSDAY AS THE HIGH MOVES EAST.
AVIATION/00Z TAFS/...
ON AND OFF LIGHT SNOW WILL CONTINUE INTO EARLY EVENING. COULD SEE
VISIBILITIES DOWN TO AROUND 4 MILES AT TIMES...WITH NOT MUCH MORE
THAN A DUSTING TO A TENTH OR TWO EXPECTED FROM HERE ON OUT. EXPECT
DRY WEATHER THEN FROM LATE EVENING THROUGH FRIDAY.
LATEST RAP AND NAM ARE SUGGESTING MOSTLY CLOUDY SKIES WILL LINGER
THROUGH MUCH OF THE NIGHT. HAVE TAFS REMAINING VFR...AS THE MAJORITY
OF UPSTREAM OBS ARE VFR. SEEING SOME MVFR MIXED IN THERE THOUGH...SO
WOULD NOT BE SURPRISED AT BRIEFLY LOWER CLOUDS THIS EVENING AND
OVERNIGHT. SHOULD SEE SOME BREAKS IN THE CLOUDS BY TOMORROW
MORNING...WITH A DECENT CHANCE AT SOME SUNSHINE BY LATE MORNING AND
AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
528 PM CST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 528 PM CST THU DEC 26 2013
A WESTERLY FLOW RIGHT ABOVE THE GROUND THROUGH THE MID LEVELS OF
THE TROPOSPHERE WILL HELP TO CLEAR SKIES OUT AROUND 06Z. THIS
CLEARING COMBINED WITH AN INCREASE OF MOISTURE AT THE GROUND TODAY
BRINGS UP A CONCERN FOR FOG/MIST. A SOUTHWESTERLY BREEZE LOOKS TO
DEVELOP AT RST AT THE TIME OF CLEARING WHICH SHOULD HELP PREVENT
VISIBILITIES FROM DROPPING BELOW MVFR. HOWEVER...LSE COULD STAY
NEARLY CALM ALL NIGHT. AS SUCH...LOWER VISIBILITY CONCERN EXISTS
THERE. KEPT THE PREVIOUS FORECAST OF LOW MVFR VISIBILITIES...AT 3
SM...IN AGREEMENT WITH STATISTICAL GUIDANCE. HOWEVER...CANNOT RULE
OUT POTENTIAL FOR IFR VISIBILITIES. ANY FOG/MIST WILL DISSIPATE
AROUND 13Z AS MIXING FROM SUN COMBINES WITH THE WIND PICKING UP.
SOME ALTOSTRATUS LOOKS TO PASS ACROSS DURING THE DAY FRIDAY...BUT
CEILINGS WILL STAY VFR. MORE SIGNIFICANT IS THE AFOREMENTIONED
WINDS WHICH LOOK TO PICK UP TOWARDS 15-20 KT AT RST AND 10-15 KT
AT LSE. A STRONG WIND CORE IS ALSO SUGGESTED TO MOVE ACROSS THE
TAF SITES BETWEEN 19-23Z...BUT BASED ON SURFACE WINDS...LOW LEVEL
WIND SHEAR IS ONLY WARRANTED AT LSE AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1039 AM CST WED DEC 25 2013
.UPDATE...
MAIN CONCERN IN THE ONGOING TODAY PERIOD IS POPS/WX AS A SWATH OF
LIGHT SNOW TAKES AIM AT THE CWA FROM SOUTHEAST MN AND NORTHERN IA.
FORECAST WAS GENERALLY ON TRACK HOWEVER...DID UPDATE POPS/WX TO
ACCOUNT FOR THE LATEST RADAR TRENDS. THE HRRR DOESNT SEEM TO BE
HANDLING THE SWATH AS WELL COMPARED TO OUR LOCAL OFFICE WRF AND
THE OTHER FLAVORS OF WRF AVAILABLE. THOUGH SAID WRF OUTPUT APPEARS
TO BE A BIT SLOW. SNOW TO LIQUID RATIOS ARE EXPECTED TO BE AROUND
17:1 AT LEAST...SO THIS SHOULD YIELD ADDITIONAL ACCUMULATIONS OF
AROUND AN HALF INCH TO AN INCH MOST PLACES. OTHERWISE...REST OF
THE FORECAST PACKAGE WAS JUST ADJUSTED TO KEEP UP WITH TRENDS.
&&
.AVIATION/18Z TAFS/...
ON AND OFF LIGHT SNOW WILL CONTINUE THROUGH LATE MORNING...WITH
VISIBILITIES GENERALLY RANGING FROM 3 TO 5 MILES. A MORE MODERATE
SNOWFALL WILL MOVE IN WEST TO EAST FROM LATE MORNING AND INTO THE
AFTERNOON...DROPPING A HALF AN INCH TO AN INCH MOST PLACES BY
EARLY EVENING. COULD SEE VISIBILITIES DOWN TO 1 MILE FOR A TIME
GIVEN UPSTREAM OBSERVATIONS.
SNOW WILL EXIT THE EAST THIS EVENING...WITH DRY WEATHER EXPECTED
OVERNIGHT. SHOULD SEE SKIES EVENTUALLY RETURN TO VFR BY LATE
TONIGHT INTO THURSDAY MORNING. YET ANOTHER WEAK SYSTEM COULD
BRING A LITTLE LIGHT SNOW BY LATE THURSDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 433 AM CST WED DEC 25 2013/
SHORT TERM...
CHRISTMAS DAY AND TONIGHT - FORECAST CONFIDENCE HIGH
IN SPITE OF DECENT FORCING...INTRUSION OF DRY AIR ABOVE 800 MB AND
THROUGH THE DENDRITE GROWTH ZONE LIMITED AMOUNTS OF SNOW FROM
INITIAL WARM ADVECTION BAND BUT SECOND BAND IS INTENSIFYING AS IT
CROSSES EASTERN HALF OF WISCONSIN WITH ISENTROPIC ADIABATIC OMEGA
INCREASING FROM 1.5 MICROBARS/SEC TO BETWEEN 2.5 AND 3.0
MICROBARS/SEC. WILL SEE BETWEEN 1/2 INCH AND 1 INCH OF ADDITIONAL
ACCUMULATION FROM THIS BAND.
A BREAK IN SNOW UNTIL NEXT SHORT WAVE DROPS INTO MN LATE THIS
AFTERNOON... DOWN THROUGH WRN WI THIS EVENING AND ACROSS SRN WI/NRN
IL OVERNIGHT. POTENT WAVE PRODUCING SUB-2 MILE VSBYS IN THE DAKOTAS.
HAVE SPREAD CATEGORICAL POPS ACROSS THE CWA FROM WEST TO EAST FROM
LATE THIS MORNING IN THE FAR WEST THROUGH THE AFTERNOON. LINGERED
POPS IN THE EAST THIS EVENING WITH DIFFERENTIAL CYCLONIC VORTICITY
ADVECTION ACTING ON A COLUMN STILL MOIST UP THROUGH DENDRITE GROWTH
ZONE UNTIL AROUND 03Z.
HIGH TEMPERATURES IN THE LOWER TO MID 20S TODAY WITH 925MB-850MB
THERMAL RIDGES PASSING THROUGH. TEMPS FALL TONIGHT WITH LOWS IN THE
SINGLE DIGITS BY THURSDAY MORNING WITH 925 MB TEMPS DROPPING INTO
THE TEENS BELOW ZERO BY 12Z.
THURSDAY-FORECAST CONFIDENCE HIGH
DEEP TROUGH MOVES EAST OF AREA WITH SIGNIFICANT 500 MB HEIGHT RISES
ON THE ORDER OF 160 METERS IN THE MORNING OVER SOUTHERN WISCONSIN.
EMBEDDED WITHIN FAST NORTHWEST FLOW WILL BE ANOTHER WEAK SHORT WAVE
TROUGH THAT WILL MOVE ACROSS THE DAKOTAS AND MINNESOTA AND INTO
WISCONSIN BY THE AFTERNOON. GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT WITH BAND OF LIGHT SNOW WITH THIS...BUT NAM IS RATHER DRY.
LEANED TOWARD FORMER SOLUTION AND WENT WITH CHANCE POPS.
ALTHOUGH 1000-500 MB THICKNESS VALUES INCREASE ABOUT 100 METERS IN A
24 HOUR PERIOD...THE LOW LEVEL THERMAL FIELD DOESN`T CHANGE MUCH SO
ONLY MINOR MODERATION EXPECTED WITH HIGHS STILL 5 TO 10 DEGREES
BELOW NORMAL.
FRIDAY-FORECAST CONFIDENCE HIGH
MILD SOUTHWEST FLOW REGIME EXPECTED WITH HEIGHTS RISING ANOTHER 70
METERS AND TEMPERATURES CLIMBING TO ABOUT NORMAL FOR LATE DECEMBER.
AIRMASS LOOKS RATHER DRY. TEMPERATURES HOLDING STEADY OR RISING IN
WARM ADVECTION PATTERN WITH SOUTHWEST FLOW AT NIGHT.
LONG TERM...
SATURDAY-FORECAST CONFIDENCE HIGH
UPPER FLOW TILTS FROM WEST-NORTHWEST TO WESTERLY AS A TROUGH DIGS
INTO NORTHERN PLAINS. FRONT STAYS WELL NORTH OF THE AREA DURING THE
DAY ALLOWING MILD AIRMASS TO OVERSPREAD SOUTHERN WISCONSIN. THIS
AIRMASS WILL BE RATHER DRY...LIMITING THE POTENTIAL FOR
PRECIPITATION AND ADVECTION FOG. LOOKS LIKE ABOVE FREEZING HIGHS IN
THE MIDDLE 30S A GOOD BET DESPITE THE DEEP SNOW COVER WITH 850 MB
TEMPS ABOVE +6C.
PARTY IS OVER AT NIGHT AS COLD FRONT SURGES THROUGH ALONG WITH 120
METER 500 MB HEIGHT FALLS. LOOKS LIKE 850 MB TEMPS CRASH ABOUT 15C
OVERNIGHT. POTENTIAL FOR POST FRONTAL FREEZING RAIN GOING OVER TO
SNOW ESPECIALLY NORTH LATER ON.
SUNDAY-FORECAST CONFIDENCE HIGH
STRONG COLD ADVECTION WITH LIKELY RESULT IN FALLING TEMPERATURES
DURING THE DAY FROM THE TEENS INTO THE SINGLE DIGITS WITH A CHANCE
OF LIGHT SNOW CONTINUING ESPECIALLY EAST.
WIND CHILL VALUES CURRENTLY FORECAST TO DROP INTO -20 TO -30 RANGE
SUNDAY NIGHT SO MAY NEED WIND CHILL HEADLINES LATER ON.
MONDAY-FORECAST CONFIDENCE HIGH
HEIGHTS AND THICKNESS JUST KEEP FALLING AS -45C 500 MB COLD CORE
MOVES ACROSS ONTARIO WITH 1000-500 MB THICKNESSES DOWN AROUND 5000
METERS OVER SOUTHERN WISCONSIN. TEMPERATURES START OUT AROUND 10
BELOW ZERO INLAND AND STRUGGLE INTO SINGLE DIGITS ABOVE ZERO DURING
THE DAY WITH WIND CHILLS ONLY ABOUT 10 BELOW ZERO.
WINDS WILL DROP OFF DURING THE AFTERNOON AS THE POLAR HIGH MOVES
OVERHEAD. LOOKS LIKE WELL BELOW ZERO AGAIN AT NIGHT WITH BETTER
RADIATION CONDITIONS WITH LOWS OF 10 TO 15 BELOW OR COLDER IN THE
WIND SHELTERED LOCATIONS.
TUESDAY-FORECAST CONFIDENCE MEDIUM
ALTHOUGH GFS IS ABOUT 6 HOURS FASTER AS IS TYPICAL VERSUS
ECMWF...BOTH MODELS BRING A RATHER SIGNIFICANT ALBERTA CLIPPER
ACROSS IOWA INTO NORTHERN ILLINOIS. VERY COLD AIRMASS AND POTENTIAL
LAKE ENHANCEMENT SITUATION WITH ECMWF SHOWING ABOUT A THIRD OF AN
INCH OF LIQUID. SO THIS COULD END UP BEING AN ADVISORY TYPE SNOW
EVENT.
--SPECIAL NOTE ABOUT DAYS 8 TO 11--
ALTHOUGH BEYOND THE FORECAST PERIOD...THE 00Z ECMWF HAS MASSIVE
HEIGHT FALLS IN A HIGH AMPLITUDE PATTERN OVER THE GREAT LAKES LATER
IN THE WEEK. A SIGNIFICANT COLD WAVE ACCOMPANIED BY BITTER WINDS IS
A POSSIBILITY.
AVIATION/12Z TAFS/...
MVFR/BRIEFLY IFR VSBYS WITH LAST OF THE MODERATE SNOW BAND EXPECTED
TO PUSH OUT OVER LAKE MICHIGAN BY 12Z. STRATUS DECK TO THE WEST ALL
THE WAY BACK TO WESTERN MN AND IA LEADS TO PESSIMISTIC SKY FORECAST
WITH MVFR CIGS EXPECTED THROUGH THE DAY. CURRENT TIMING OF SNOW WITH
NEXT WAVE BRINGS MVFR/BRIEF IFR VSBYS TO KMSN BETWEEN 17Z AND
18Z...KUES AROUND 19Z AND TO KMKE AND KENW BETWEEN 1930Z AND 20Z.
LOOKING AT A 3-4 HOUR PERIOD OF STEADY LIGHT...TO AT TIMES
MODERATE...SNOW WITH UP TO ANOTHER INCH OF SNOW BY EVENING IN SOME
LOCATIONS. LINGERING LIGHT SNOW UNTIL 03Z AT EASTERN TAF SITES.
MARINE...
WILL KEEP CURRENT END TIME OF SMALL CRAFT ADVISORY AT 00Z AS
APPROACHING TROUGH WILL LOWER SOUTHWEST WINDS THIS
AFTERNOON...THEN BACK WINDS TO THE WEST WITH TROUGH PASSAGE EARLY
THIS EVENING AND FURTHER EASE TO 10 TO 15 KNOTS. WAVES WILL SLOWLY
SUBSIDE DURING THE DAY WITH THE DEVELOPING OFFSHORE FETCH AND
LOWERING WIND SPEEDS. WINDS AND WAVES STILL LOOK TO BE BELOW
CRITERIA BY EARLY THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...CRAVEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
354 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY-SUBSIDENCE INVERSION ACROSS
THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS FROM
GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH THE
AFOREMENTIONED INVERSION AS WEAK MID-LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE... UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN OPEN
RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST THROUGH
QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS THROUGH NEW
ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS MOVES THROUGH
WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR WEST THROUGH
MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY NIGHT. THIS
CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY WITH A
SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS DOES MOVE
THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND BURST OF COLD
AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE NOTICE THE DIFFERENCE?
MODELS... THERE IS GENERAL AGREEMENT ON THE PATTERN BUT DIFFERENCES
IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL STORM ON SUNDAY.
THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST WITH THE
STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE ECMWF IS
FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY SNOW OR
A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A BLEND OF
MODEL VALUES.
THE DAILIES...
SUNDAY... SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT OUTSIDE
CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE MAINLY
AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO THIS
LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A LITTLE
COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND COULD
SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND 1 AM
MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND BRING
COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD OF SNOW
MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY... NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND. BUT
WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A TRANSITION
DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE AFTERNOON. THIS
WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS ALOFT WILL CENTER
AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN THE 30S AND LOWER
40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY... ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE EQUIVILENT
TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE TEMPS SHOULD BE
ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE NUMBERS EITHER SIDE
OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE SINGLE NUMBERS AND
POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
9Z UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
308 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS IN VICINITY OF SOUTHEAST NEW
ENGLAND SUNDAY INTO SUNDAY NIGHT AS MOSTLY RAIN WITH AN INTERIOR
WINTRY MIX. FRIGID ARCTIC AIR WILL INVADE THE REGION BY TUESDAY
WITH BELOW ZERO READINGS POSSIBLE ACROSS INTERIOR NEW ENGLAND.
&&
.NEAR TERM /THROUGH TODAY/...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY-SUBSIDENCE INVERSION ACROSS
THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS FROM
GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH THE
AFOREMENTIONED INVERSION AS WEAK MID-LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
STRONG STORM SYSTEM SUNDAY NIGHT CAUSING A VARIETY OF WEATHER...
BITTERLY COLD WEATHER MIDWEEK...
SATURDAY...HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND OUT
TO SEA. SOUTHWEST WINDS OVER SOUTHERN NEW ENGLAND HELP USHER MILDER
AIR INTO THE REGION. 850 MB TEMPERATURES WARM ALL THE WAY TO +4C TO
+5C BY EVENING. HIGHS IN THE LOW TO MID 40S. LOWS SATURDAY NIGHT IN
THE 20S TO MID 30S EXCEPT UPPER 30S ON THE ISLANDS.
SUNDAY AND SUNDAY NIGHT...UPPER LEVEL ENERGY WILL HEAD NORTHEAST
FROM THE TENNESSEE VALLEY AND HELP INTENSIFY A LOW PRESSURE SYSTEM
OFF THE NEW JERSEY COAST SUNDAY NIGHT. THE LOW ORIGINATES IN THE
GULF OF MEXICO SATURDAY EVENING AND RACES NORTHEAST TO THE NEW
JERSEY COAST SUNDAY EVENING...THEN CONTINUES RACING TO A POSITION
JUST SOUTH OF NOVA SCOTIA MONDAY MORNING. MODELS HAVE COME INTO
QUITE GOOD AGREEMENT ON THE RAPID INTENSIFICATION OF THIS SYSTEM AS
IT PASSES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT. THE NAM IS
WARMEST AND HAS BEEN DISREGARDED...IN FAVOR MORE OF A ECMWF/ECMWF
ENSEMBLE/GFS/UKMET SOLUTION WHICH IS A TAD FARTHER SOUTHEAST AND
COOLER THAN PREVIOUS SOLUTIONS.
THIS STORM WILL BRING A VARIETY OF IMPACTS. WE WILL BE STARTING OFF
VERY WARM ON SUNDAY...WITH HIGHS IN THE 40S THROUGHOUT THE FORECAST
AREA. RAIN IS FORECAST TO MOVE IN FROM SOUTH TO NORTH IN THE MID TO
LATE AFTERNOON. THE RAIN MAY BECOME HEAVY AT TIMES SUNDAY NIGHT AS
ALL MODELS SHOW VERY STRONG 700 MB OMEGA BETWEEN 00Z AND 03Z MONDAY.
THE 850-700 MB THICKNESS LINE OF 1540...OFTEN DENOTING THE RAIN/SNOW
LINE...IS FORECAST TO STRETCH FROM THE SOUTHERN BERKSHIRES
NORTHEASTWARD TO CAPE ANN AT 00Z. DESPITE ACTUAL WINDS FROM THE
NORTHEAST TO EAST...THE AGEOSTROPHIC SURFACE WIND IS FROM THE NORTH
WHICH COULD LEAD TO MORE LOW-LEVEL COLD AIR DRAINAGE THAN ONE WOULD
OTHERWISE THINK. GFS AND ECMWF SURFACE TEMPERATURES SHOW THE 32
DEGREE LINE A HAIR SOUTH OF THE 1540 THICKNESS LINE...WHICH MAY
SPELL THE POTENTIAL FOR A NARROW SWATH OF FREEZING RAIN. THIS WOULD
BE MOST LIKELY IN CENTRAL MA NORTHEASTWARD THROUGH THE MERRIMACK
VALLEY TO CAPE ANN...PERHAPS AS FAR SOUTHWEST AS THE SPRINGFIELD
AREA. IN NORTHWEST MA AND SOUTHERN NH...ANY RAIN SHOULD TURN
DIRECTLY TO SNOW.
THE FACT THAT THIS IS SUCH A QUICK-HITTING SYSTEM SHOULD WORK TO OUR
BENEFIT. RAINFALL TOTALS IN EASTERN CT/RHODE ISLAND/SOUTHEAST MA
COULD REACH 1 TO 1.5 INCHES. THIS IS NOT ENOUGH TO CAUSE RIVER
FLOODING BUT MAY CAUSE SOME LOCALIZED STORM DRAINAGE TYPE OF
FLOODING. THE DURATION OF ANY FREEZING RAIN WILL ONLY BE ABOUT 2-6
HOURS...AND THUS AMOUNTS WOULD LIKELY ONLY REACH A FEW TENTHS...NOT
ENOUGH FOR A WARNING...BUT AN ADVISORY COULD BE NEEDED. AND AS FOR
SNOW...WE ARE THINKING THAT ACCUMULATIONS IN NW MA AND SOUTHERN NH
COULD REACH A FEW INCHES AFTER THE CHANGEOVER FROM RAIN...BUT ALL
PRECIPITATION WILL BE ENDING FROM SW TO NE ACROSS THE REGION BY 06Z
MONDAY - JUST AFTER MIDNIGHT...SO PROBABLY STAYING JUST BELOW
ADVISORY CRITERIA. OBVIOUSLY...WE WILL HAVE A BETTER HANDLE WITH
THIS SYSTEM AS TIME GETS CLOSER.
MONDAY THROUGH THURSDAY...AFTER THE STORM SYSTEM DEPARTS EARLY
MONDAY...ATTENTION WILL THEN FOCUS ON THE BITTERLY COLD WEATHER
THAT WILL GRIP OUR REGION AROUND THE NEW YEARS HOLIDAY. IN
GENERAL THE WEATHER WILL BE DRY THROUGH THAT PERIOD ALTHOUGH THERE
ARE DIFFERENCES IN TIMING OF WEAK LOW PRESSURE SYSTEMS THAT PASS
EITHER NORTH OF SOUTH OF US ON VARIOUS MODELS. LET/S CALL IT
PARTLY SUNNY BY DAY AND PARTLY CLOUDY BY NIGHT THROUGH THE PERIOD.
THE ONE THING THAT IS FOR SURE IS THAT NORTHWESTERLY FLOW CAUSES
FRIGID AIR TO GRADUALLY SEEP INTO SOUTHERN NEW ENGLAND STARTING
MONDAY AND BY WEDNESDAY AND THURSDAY WE ARE IN THE DEEP FREEZE.
THE GFS HAS THE DEEP FREEZE ARRIVING A DAY LATER AND LASTING
LONGER THAN THE ECMWF. BUT IN EITHER CASE...850 MB TEMPERATURES
EVENTUALLY PLUNGE TO BETWEEN -20C AND -25C...WITH THE POSSIBILITY
OF -30C IN NORTHERN NEW ENGLAND.
WE ARE FORECASTING OVERNIGHT LOWS TO REACH BELOW ZERO IN SOUTHERN
NH ON NEW YEARS EVE/TUE NIGHT/ AND ABOUT 5 BELOW ZERO THERE ON
WEDNESDAY NIGHT. THIS MAY BE EVEN BE TOO CONSERVATIVE. LOWS WILL
REACH THE SINGLE DIGITS AND LOWER TEENS ACROSS THE REST OF
INTERIOR SOUTHERN NEW ENGLAND BOTH NIGHTS...EXCEPT MID TO UPPER
TEENS SOUTH COAST AND LOWER 20S ON THE ISLANDS. WIND CHILL INDICES
COULD REACH 10 TO 15 BELOW ZERO IN THE EARLY MORNING HOURS ON WED
AND THU ACROSS NORTHERN AND WESTERN MA AND IN SOUTHERN NH.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
9Z UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SATURDAY THROUGH EARLY SUNDAY AFTERNOON...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. WIDESPREAD IFR SUNDAY NIGHT. PRECIPITATION MAY CHANGE TO
ALL SNOW IN NW MA AND SOUTHERN NH EARLY SUNDAY NIGHT. THERE COULD
BE A BAND OF FREEZING RAIN IN CENTRAL AND NORTHEAST MA. RAIN MAY
BE HEAVY AT TIMES IN RI AND SOUTHEAST MA. ALL PRECIPITATION ENDS
SHORTLY AFTER MIDNIGHT MONDAY MORNING. CONDITIONS IMPROVING TO VFR
MONDAY.
TUE...MODERATE TO HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SATURDAY THROUGH TUESDAY...
MODERATE CONFIDENCE.
SMALL CRAFT ADVISORIES WILL PROBABLY BE NEEDED SAT AS SOUTHWEST
WINDS COULD GUST TO 20 TO 30 KT OVER THE SOUTHERN AND EASTERN
WATERS AND SEAS COULD REACH 5 TO 7 FT OVER THE SOUTHEASTERN OUTER
WATERS.
SUNDAY INTO MONDAY...STRONG COASTAL LOW PRESSURE MOVES UP THE
EAST COAST AND INTENSIFIES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT
REACHING NOVA SCOTIA MONDAY MORNING. WINDS WILL BECOME
SOUTHEAST...THEN NORTHEAST...THEN NORTHWEST AS THE LOW PASSES.
WINDS COULD GUST TO 25 TO 30 KT AT TIMES OVER THE SOUTHEAST
WATERS BUT GALES ARE NOT EXPECTED AT THIS TIME. SEAS WILL BE QUITE
ROUGH...BUILDING UP TO 6 TO 10 FT JUST OFF THE COAST AND TO 12 FT
OVER THE OUTER WATERS SUNDAY NIGHT...SLOWLY SUBSIDING ON MONDAY.
TUESDAY...WINDS AND SEAS SUBSIDE TO BELOW SMALL CRAFT ADVISORY
LEVELS.
TUESDAY NIGHT...THERE IS THE POTENTIAL FOR SOME FREEZING SPRAY
OVER THE WATERS OFF OF NORTHERN MA LATE AT NIGHT AS VERY COLD
TEMPERATURES MOVE OVER THE REGION.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/GAF
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...GAF
AVIATION...SIPPRELL/GAF
MARINE...SIPPRELL/GAF
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
425 AM EST Fri Dec 27 2013
.NEAR TERM [Today and Tonight]...
Early morning surface analysis reveals the forecast area locked in
northeasterly flow with an approximately 1030mb high pressure
centered to the north and west (Arklatex to Kentucky). This
surface flow pattern exists up the east coast, and over much of
the Gulf of Mexico. Higher thetae air is displaced well to the
south over south Florida and the southern Gulf of Mexico.
Meanwhile, the weather over our forecast area is relatively
unchanged from the past 12-24 hours with cloudy, cool conditions
and some intermittent very light rain showers. This should
continue during the day today with a mixture of low and mid level
cloud decks. RAP analysis shows a significant 850mb dewpoint
gradient bisecting our area from SW-NE (roughly from PAM-FZG).
This is confirmed by comparing the 00z sounding from TAE with ones
to the north and west (LIX, BMX, FFC). Therefore, the southeastern
half of our area is situated in a region of greater low-level
moisture. This is where some light rain showers or patchy drizzle
will be possible today. Some weak isentropic ascent is forecast in
the 290-295K planes; the ascending flow in these layers is only
around 5-10 knots so the forcing should be fairly limited.
However, the forcing should be sufficient for drizzle or light
showers, and this is confirmed by some weak returns on the TLH
radar over the past few hours. The isentropic ascent should both
deepen and increase overnight as wind fields increase - and this
is when rain showers should spread into much of the forecast area.
.SHORT TERM [Saturday through Sunday]...
Fairly active weather pattern stetting up for the weekend as an
upper low evolving over nrn Mexico/SW TX today ejects enewd across
the central Gulf coast states/sern US this weekend as a
deamplifying trough. Ahead of this system, responding sly low
level winds across the Gulf coast/ern GoM this weekend will
increase low level WAA/ascent and bring both an increase in clouds
and rising PoPs Saturday and Sunday. Rain showers are expected to
develop over the wrn counties Saturday into Saturday night,
spreading ewd across remainder of the area into Sunday. This will
keep things seasonably cool/wet Saturday over sern AL, inland
parts of the FL panhandle into swrn GA. This system will be fast
moving so rain totals are expected to be around 1-1.5 inches over
most areas. Sunday should see fairly steady improvements with rain
chances ending from west to east through the day. Given the expect
cool air and little time for recovery, expect thunderstorms will
remain most likely over the Gulf of Mexico. However will include
slgt chance or chance of tstms spreading inland Saturday afternoon
into Sunday as warm sector becomes better defined over the nern
Gulf. Overall risk of severe storms appears fairly low attm given
the expected limited instability. Regardless, increasing low and
deep layer shear suggest an isolated strong to severe storm
remains possible.
.LONG TERM [Sunday Night Through Friday]...
The extended period begins with a cold front pushing through the
Tri-state region with rain ending from west to east Sunday. This
will be quickly followed by a dry cold front Monday as an amplifying
upper trough over the nation`s midsection moves east. In its wake,
we can expect at least two more days with cooler and dry weather.
Wednesday night through Thursday, cyclogenesis is forecast to
develop along the Central Gulf coast in response to the next
shortwave dropping down into the Southern plains. The surface low
with this system is currently forecast to be rather weak and pass
over or south of our coastal waters. For now, will just introduce
slight PoPs for all zones for Thursday. Temps will be at or below
seasonal levels through the period.
&&
.AVIATION...
[Through 06Z Saturday] Ceilings are expected through the TAF
period with BKN-OVC skies, but these should mainly be of the VFR
variety. There could be some brief periods of MVFR, particularly
at ECP, TLH, or VLD. However, probabilistic guidance indicates
that the chances of this happening are around 20-30%. Therefore,
we indicated a VFR forecast. Some very light rain showers or
drizzle is expected to develop this morning in the Florida Big
Bend, which could affect TLH and VLD. Showers spread inland
tonight - to TLH, VLD, and ECP prior to 06z, and ABY and DHN after
06z (the end of the TAF period).
&&
.MARINE...
Northeast winds will remain at cautionary levels today and
tonight, and hold in the 15-20 kt range Saturday as winds switch
to a more easterly direction and rain chances increase. By
Saturday night into Sunday winds will become more out of the
southeast and increase over wrn legs to near advisory criteria as
a surface low moves into the FL panhandle. Winds and seas are
expected to subside early next week.
&&
.FIRE WEATHER...
Relative humidity will remain well above critical thresholds.
Therefore, red flag conditions are not expected. Wetting rains are
likely this weekend.
&&
.HYDROLOGY...
The Apalachicola River at Blountstown is expected to remain in
minor flood stage through the weekend with releases from
Woodruff Dam. The Kinchafoonee Creek`s crest near Dawson is
forecast to just barely reach minor flood stage early Friday
morning and drop below minor flood stage on Friday evening. The
Choctawhatchee River at Caryville is expected to barely reach
minor flood stage on Friday morning and drop below minor flood
stage Saturday morning.
Early projections on rainfall this weekend are in the 1-2" range.
This should help to keep river levels elevated.
&&
.PRELIMINARY POINT TEMPS/POP...
Tallahassee 60 48 66 58 69 / 20 30 50 70 50
Panama City 61 50 63 58 65 / 20 50 60 80 40
Dothan 59 45 57 49 62 / 10 30 70 80 40
Albany 58 42 58 51 66 / 10 20 60 80 50
Valdosta 58 45 67 57 70 / 20 30 50 70 60
Cross City 64 51 73 61 73 / 30 30 40 60 60
Apalachicola 62 52 67 59 68 / 30 40 50 70 50
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Evans
LONG TERM...Barry
AVIATION...Lamers
MARINE...Evans
FIRE WEATHER...Lamers
HYDROLOGY...DVD/McDermott
AREA FORECAST DISCUSSION
NWS GOODLAND KS
204 AM MST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 201 AM MST FRI DEC 27 2013
LARGE SCALE PATTERN IS STILL SHOWING THE UPPER TROUGH OVER THE
EASTERN U.S. WITH THE UPPER RIDGE OVER THE WESTERN U.S. THE
EXTENDED STILL LOOKS TO REMAIN DRY WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE NORMAL...WITH A BRIEF COOL DOWN ON TUESDAY
NIGHT/WEDNESDAY...WARMING UP TOWARDS THE END OF THE EXTENDED.
THE CWA WILL BE UNDER NORTHWEST FLOW ALOFT WITH A MID-UPPER LEVEL
SHORTWAVE TROUGH MOVING THROUGH THE CENTRAL PLAINS ON WEDNESDAY. A
BACK DOOR COLD FRONT WILL MOVE THROUGH THE CWA ON TUESDAY
EVENING...BRINGING IN COLDER TEMPERATURES. THE NEW ECMWF MODEL RUN
BROUGHT IN MUCH COLDER ARCTIC AIR THAN THE OTHER MODELS. SINCE THIS WAS
THE FIRST RUN TO DO THIS...ADJUSTED TEMPS SLIGHTLY FOR LOWS ON
TUESDAY NIGHT/WEDNESDAY MORNING AND HIGHS ON WEDNESDAY AFTERNOON IN
THE NORTHEAST/EASTERN COUNTIES OF THE CWA WHERE THE COLD AIR WILL
FILTER IN. COULD NOT REALLY LOWER TEMPS A WHOLE LOT TO BE IN
AGREEMENT WITH SURROUNDING OFFICES...SO WILL HAVE TO SEE WHAT MODELS
DO TOMORROW TO SEE IF THE ECMWF IS AN OUTLIER. CLOUD COVER WILL
INCREASE ON WEDNESDAY AS THE SHORTWAVE TROUGH MOVES THROUGH AND
SOUNDINGS BECOME MORE SATURATED AT THE MID-UPPER LEVELS...BUT THE EXTENDED
WILL REMAIN DRY. HIGHS SHOULD INCREASE AND BECOME ABOVE NORMAL IN
THE UPPER 40S ON THURSDAY AS THE COLD AIR EXITS THE AREA...WITH THIS
WARMING TREND TO CONTINUE PAST DAY 7.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1014 PM MST THU DEC 26 2013
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. SURFACE
WINDS WILL BE LIGHT AND MAINLY OUT OF THE WEST WITH A SURFACE
TROUGH NEARLY STATIONARY ACROSS EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...ALW
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1017 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 145 PM MST THU DEC 26 2013
FRIDAY NIGHT-SUNDAY...CONTINUED WARM AND DRY SATURDAY AHEAD OF AN
UPPER TROUGH THAT MOVES THROUGH SATURDAY NIGHT. ON SUNDAY FORECAST
AREA UNDER NORTHWEST FLOW ALOFT. AHEAD OF THE UPPER TROUGH STRONG
NORTH/NORTHWEST WINDS MOVE IN EARLY SATURDAY AFTERNOON WITH
SUSTAINED SPEEDS AROUND 20-30 MPH WITH HIGHER GUSTS. SOME GUSTY
WINDS CONTINUE THROUGH EARLY SATURDAY NIGHT BEFORE SLOWLY DECREASING
AFTER MIDNIGHT AND THROUGH THE DAY SUNDAY. CANT COMPLETELY RULE OUT
SOME VERY LIGHT PRECIPITATION CHANCES EARLY SATURDAY NIGHT AS BETTER
MOISTURE BUT LIMITED DYNAMICS WITH THE UPPER TROUGH MOVE THROUGH.
AFTER MIDNIGHT MOISTURE QUICKLY MOVES AWAY FROM THE AREA WITH NEAR
ZERO CHANCE ON SUNDAY.
LOWS TONIGHT UPPER TEENS TO MID 20S WITH HIGHS SATURDAY MID 50S TO
LOW 60S. LOWS SATURDAY NIGHT IN THE TEENS WITH MID 20S (EAST) TO
LOW/MID 30S FAR WEST SUNDAY.
SUNDAY NIGHT-THURSDAY...FORECAST AREA REMAINS UNDER NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. WEATHER SYSTEMS MOVE THROUGH THE FLOW
SUNDAY NIGHT THEN AGAIN MONDAY NIGHT AND TUESDAY NIGHT.
HOWEVER...DOESNT LOOK LIKE ANY OF THESE PRODUCE ANY PRECIPITATION.
TEMPERATURES SLOWLY WARM MONDAY AND TUESDAY BEFORE COOLING DOWN
WEDNESDAY AND THEN WARMING UP AGAIN THURSDAY.
LOWS SUNDAY NIGHT IN THE TEENS WITH LOW TO MID 20S MONDAY
NIGHT-WEDNESDAY NIGHT. HIGHS MONDAY LOW TO MID 40S ALTHOUGH
GFS/ECMWF 850 TEMPS SUPPORT READINGS A BIT HIGHER. FOR TUESDAY LOW
TO MID 40S EAST WITH UPPER 40S TO LOW 50S WEST. ON WEDNESDAY AN
UNCERTAIN LOW TO MID 40S AS DIFFERENCES SHOW UP IN JUST HOW MUCH
COOLER IT WILL BE WITH LARGE DISPARITY BETWEEN ECMWF/GFS 850
TEMPERATURES. FOR THURSDAY GENERALLY MID TO UPPER 40S...ECMWF
SUGGESTS IT WILL BE WARMER THEN CURRENT FORECAST PER 850
TEMPERATURES WHILE GFS ABOUT 5C COOLER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1014 PM MST THU DEC 26 2013
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. SURFACE
WINDS WILL BE LIGHT AND MAINLY OUT OF THE WEST WITH A SURFACE
TROUGH NEARLY STATIONARY ACROSS EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1144 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1144 PM EST THU DEC 26 2013
CMX...EXPECT MVFR CONDITIONS UNTIL MORNING AS LAKE EFFECT SNOW BANDS
DRIFT TO THE NORTH OF THE SITE. VFR WX SHOULD THEN DOMINATE ON FRI
MRNG WITH A DRIER SW FLOW DESPITE A GOOD DEAL OF MID CLD COVER. AS
WINDS TURN TO THE WEST FRI EVENING...MVFR CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS RETURN.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW EARLY THIS
MORNING...EXPECT VFR WX FOR MOST OF THIS FCST PERIOD WITH A DRY W-SW
FLOW TO THE NW OF HI PRES MOVING TOWARD THE LOWER GRT LKS. WILL GET
GUSTY AT BOTH SITES LATE FRI MORNING. MVFR CONDITIONS RETURN TO IWD
BY FRI EVENING WITH LAKE EFFECT CLOUDS COMING BACK IN ON WEST WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1139 PM EST THU DEC 26 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST OF THE LAKES OVERNIGHT WITH
LOCALIZED HEAVY ACCUMULATIONS EAST OF LAKE ONTARIO. A WEAK
DISTURBANCE MAY BRING A GENERAL LIGHT SNOW FRIDAY MORNING WITH LAKE
EFFECT SNOW SLOWLY TAPERING OFF EAST OF THE LAKES AS HIGH PRESSURE
EDGES NORTHWARD INTO THE REGION. A TEMPORARY WARMING TREND IS THEN
EXPECTED FOR THE WEEKEND BEFORE A SURGE OF ARCTIC AIR ARRIVES NEXT
WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
WESTERLY FLOW LAKE SNOWS WILL CONTINUE ACROSS THE TUG HILL PLATEAU
GIVEN THE FULL LAKE FETCH AND CLOSER LOCATION OF LEFT ENTRANCE
REGION OF UPPER JET. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR
WILL BE COMMON WITHIN THE HEART OF THE BAND. A LAKE SNOW WARNING
WILL BE MAINTAINED FOR THE TUG HILL REGION WITH SNOWFALL TOTALS
EXCEEDING A FOOT.
LAKE ERIE SNOWS HAVE DIMINISHED CONSIDERABLY THE PAST FEW HOURS.
LATEST HRRR AND LOCAL WRF SHOWING THIS DIMINISHING TREND NICELY.
THEREFORE HAVE CANCELED THE ADVISORY FOR THIS AREA. MESOSCALE
MODELS DO SUGGEST SOME REDEVELOPMENT OFF LAKE ERIE LATE TONIGHT
AND FRIDAY MORNING...BUT THIS WILL BE FOCUSED ON A SOUTHWEST FLOW
WITH A LAKE BAND LIKELY TO DEVELOP TOWARD THE SUBURBS SOUTH OF
BUFFALO WITH A SNOWBURST DURING THE EARLY MORNING COMMUTE...THEN
SLIPPING BACK TO THE SOUTH AND WEAKENING BY MID MORNING.
TEMPERATURES OVERNIGHT WILL FALL TO THE MID TEENS TO LOW 20S...
MODERATED FROM FALLING TOO FAR BY PARTIAL CLOUD COVER AND WESTERLY
WINDS BACKING TO SOUTH BY DAYBREAK. HIGH TEMPS ON FRIDAY WILL BE
IN THE UPPER 20S TO LOWER 30S...MILDER THAN HAVE BEEN THE PAST FEW
DAYS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
WHILE A DEEP POLAR VORTEX WILL REMAIN IN PLACE IN THE VCNTY OF
HUDSON BAY DURING THIS PERIOD...THE UPPER LEVEL FLOW ACROSS THE
GREAT LAKES WILL LARGELY BE ZONAL. THIS WILL TEMPORARILY BLOCK THE
SUPPLY OF VERY COLD AIR...WHILE EXPANSIVE SFC HIGH PRESSURE OVER
THE SOUTHEAST WILL CIRCULATE MILDER CONDITIONS NORTHWARDS ACROSS
OUR REGION. OTHERWISE...UNEVENTFUL WEATHER CAN BE EXPECTED UNTIL
LATER IN THE WEEKEND WHEN A COMPLEX STORM SYSTEM FEATURING A
COASTAL LOW WILL HAVE TO BE WATCHED.
UP UNTIL THAT TIME...THE SYNOPTIC PATTERN ACROSS OUR REGION WILL BE
SIMPLE AND STRAIGHTFORWARD. FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...A LARGE AREA OF HIGH PRESSURE WILL BE ROOTED ACROSS ALL OF
THE DEEP SOUTH WHILE AN ARCTIC FRONTAL BOUNDARY STRETCHING FROM
CENTRAL QUEBEC TO THE UPPER GREAT LAKES WILL SLOWLY SAG SOUTH
TOWARDS OUR REGION. THIS WILL ENCOURAGE MODERATELY STRONG WARM
ADVECTION ACROSS THE LOWER GREAT LAKES REGION SO THAT H85 TEMPS WILL
FLEETINGLY VISIT THE POSITIVE SIDE OF ZERO C. AFTERNOON HIGHS ON
SATURDAY SHOULD BE WITHIN A COUPLE DEGREES OF 40F...WHILE OVERNIGHT
LOWS WILL BE IN THE UPPER 20S AND LOWER 30S. MEANWHILE THE CLOSEST
PCPN DURING THIS 24 HOUR WINDOW WILL BE NORTH OF THE THOUSAND
ISLANDS.
THINGS WILL THEN BECOME MORE COMPLICATED ON SUNDAY.
A WAVE OVER LAKE MICHIGAN WILL LIFT NORTHEAST ALONG THE NEARLY
STALLED ARCTIC FRONTAL BOUNDARY AND TRANSFER SOME OF ITS ENERGY TO A
SOUTHERN STREAM LOW THAT WILL BE WORKING UP THE MID ATLANTIC COAST.
THIS WILL PLACE THE BULK OF OUR FORECAST AREA IN A `RIP OFF ZONE` OF
SORTS...BETWEEN THE TWO MAIN CENTERS OF SYNOPTIC FORCING. THIS WILL
INCLUDE A STRONG AREA OF JET INDUCED LIFT THAT WILL TRACK BY JUST TO
OUR SOUTHEAST. WHILE THERE COULD BE A LITTLE LIGHT SNOW AROUND...
MAINLY ACROSS THE SRN TIER AND PORTIONS OF THE FINGER LAKES...
ACCUMULATIONS SHOULD BE INSIGNIFICANT. TEMPERATURES MAY EVEN BE HIGH
ENOUGH TO MIX IN OR CHANGE THE PCPN TO A SHORT PERIOD OF LIGHT RAIN.
AS THE NRN BRANCH LOW MOVES BY AND COMPLETES ITS ENERGY TRANSFER TO
THE COAST SUNDAY EVENING...THE ARCTIC FRONT THAT IT USED AS A
PATHWAY WILL SURGE ACROSS OUR FORECAST AREA. THIS WILL PLUNGE OUR
TEMPERATURES BACK BELOW NORMAL VALUES...INTO THE TEENS FOR MANY
AREAS. THESE VALUES WILL BE ABOUT 15 DEG LOWER THAN THOSE FROM THE
PREVIOUS COUPLE NIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE NORTHERN HEMISPHERE WILL FEATURE ANOMALOUSLY STRONG RIDGING OVER
THE RUSSIAN ARCTIC AND A LARGE POLAR VORTEX ACROSS THE HUDSON BAY
WHICH WILL SET THE STAGE FOR A CROSS POLAR FLOW. THE COLDEST OF THE
AIR (H85 -40C) HOWEVER...WILL REMAIN LOCKED UP OVER FAR NORTHERN
ONTARIO AND QUEBEC. A LITTLE CLOSER TO HOME...THE DEEP FULL LATITUDE
TROUGH MENTIONED OVER EASTERN NORTH AMERICA WILL CAUSE SOME OF THE
ARCTIC AIR (-22C) TO SETTLE SOUTH ACROSS WESTERN AND NORTH CENTRAL
NY DURING THIS PERIOD.
A POTENT FRONTAL BOUNDARY WILL SURGE ACROSS OUR FORECAST AREA SUNDAY
NIGHT INTO THE EARLY MORNING HOURS ON MONDAY. THERE WILL ALSO BE
THE POTENTIAL FOR A BRIEF PERIOD OF HEAVY SNOWFALL ACCOMPANYING THE
FRONTAL PASSAGE. BEHIND THE ARCTIC FRONT...A FRIGGED AIR MASS WILL SPILL
IN ACROSS WESTERN AND NORTH CENTRAL NY (850H TEMPS FALLING FROM -4C
TO -20 BY MONDAY NIGHT)WITH SOME MEASURE OF LAKE EFFECT SNOWS. THE
LARGE POLAR VORTEX OVER HUDSON BAY WILL SLOWLY DRIFT EASTWARD MONDAY
NIGHT INTO TUESDAY...AS IT DOES A WEAK CLIPPER TYPE SYSTEM WILL MOVE
THROUGH THE BASE OF THE TROUGH. THIS SYSTEM WILL BRING A CHANCE FOR
SOME MORE LIGHT SNOWS DURING THE DAY ON TUESDAY. FOLLOWING ITS
PASSAGE...A RE-ENFORCING SHOT OF COLD AIR WILL FILTER IN ACROSS THE
REGION (85H BACK TO -21C) AND ANOTHER ROUND OF LAKE EFFECT SNOWS
WILL DEVELOP OFF OF BOTH LAKE ERIE AND ONTARIO.
THE ECMWF/GFS SUGGEST THAT A WEAK SURFACE HIGH WILL BUILD SLOWLY
INTO THE REGION LATE WEDNESDAY. MEANWHILE ANOTHER CLIPPER TYPE STORM
SYSTEM MAY BE CROSSING THE UPPER GREAT LAKES. ALTHOUGH...AT THIS
POINT SLIGHT DIFFERENCES ARISE WHETHER THURSDAY WILL BE A RATHER
QUIET WX DAY OR THERE WILL BE SOME MORE LIGHT SNOW FROM THIS
CLIPPER SYSTEM MOVING ACROSS THE GREAT LAKES. ONE THING IS FOR
SURE...TEMPERATURES DURING THIS PERIOD WILL DEFINITELY BE BELOW
AVERAGE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THE MAIN IMPACT ON AVIATION THROUGH OVERNIGHT WILL BE LAKE EFFECT
SNOWS EAST OF THE LAKES WITH AREAS OF IFR VSBY AFFECTING MAINLY
AREAS BETWEEN KBUF AND KJHW AND BETWEEN KART AND KFZY.
THERE MAY BE A NORTHWARD MOTION TO BRING IFR VSBY TO KBUF AND KIAG
FROM 09Z TO 13Z AND KART FROM 12Z TO 16Z.
OUTLOOK...
FRIDAY...MVFR/IFR IN LIGHT SNOW IMPROVING TO VFR IN THE AFTERNOON.
SATURDAY AND SUNDAY...MAINLY VFR.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. LOCAL
IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF THE LAKES.
&&
.MARINE...
MODERATE SOUTHERLY WINDS EARLY THIS MORNING WILL BECOME MORE
SOUTHWEST AND WEST TODAY WITH MODERATE WESTERLIES CONTINUING THROUGH
TONIGHT. THIS WILL PRODUCE ONGOING SMALL CRAFT ADVISORY CONDITIONS
ON BOTH LAKES THROUGH FRIDAY MORNING. A BRIEF DIMINISHING TREND IN
WINDS IS POSSIBLE FOR A FEW HOURS FRIDAY AFTERNOON BEFORE PICKING UP
AGAIN FRIDAY NIGHT THROUGH AT LEAST SATURDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST FRIDAY FOR NYZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LOZ042.
&&
$$
SYNOPSIS...TMA/WCH
NEAR TERM...TMA/WCH
SHORT TERM...RSH
LONG TERM...AR/RSH
AVIATION...TMA/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
347 AM CST FRI DEC 27 2013
.SHORT TERM (TODAY THROUGH SATURDAY)...RAIN IS OCCURRING OVER MUCH
OF THE CWA...AND THIS SHOULD CONTINUE THROUGH ABOUT MID MORNING
BEFORE IT BEGINS TO TAPER OFF. HRRR MODEL SHOWING WIDESPREAD LIGHT
RAIN THROUGH ABOUT 15Z...THEN TAPERING OFF LATE IN THE MORNING. THIS
RAIN IS DUE TO UPPER SUPPORT IN THE FORM OF RRQ OF JET AND Q-VECTOR
CONVERGENCE...BOTH OF WHICH WILL BE LESS OF A FACTOR BY THIS EVENING
(SOME WEAK UPGLIDE AS WELL). GUIDANCE IS GOING CHANCE TO LIKELY
POPS...AND SEE NO NEED TO QUARREL WITH THIS. WOULD BE TEMPTED TO GO
EVEN A BIT HIGHER ON POPS SOME AREAS BUT RAIN COULD END OVER SOME
AREAS SHORTLY AFTER 12Z WHEN FORECAST BEGINS. WITH RAIN CHANCES
DIMINISHING BY MID AFTERNOON...AM GOING WITH SLIGHT CHANCE POPS
NORTHEAST (SOME DRY AIR MOVING IN)...WITH CHANCE POPS FARTHER WEST.
RAIN AND CLOUD COVER SHOULD KEEP TEMPERATURES DOWN AGAIN TODAY...AND
AM GOING ON THE LOW SIDE OF GUIDANCE. FOR TONIGHT...MEASURABLE RAIN
SHOULD BE ISOLATED AT BEST WITH RRQ EXITING. HOWEVER...COULD BE WEAK
UPGLIDE WESTERN AREAS TONIGHT AND SOME POSSIBLE LFQ JET DYNAMICS.
FOR SATURDAY...LIGHT RAIN (IF ANY) SHOULD BE RESTRICTED TO THE
COASTAL COUNTIES (AND OFFSHORE) WITH WEAK MOISTURE ADVECTION AND
SOME WEAK DYNAMICS ALOFT. COULD SEE SOME CLEARING SATURDAY
AFTERNOON...SO AM GOING TO GO A BIT WARMER ON THE FORECAST.
&&
.MARINE (TODAY THROUGH SATURDAY)...GRADUAL WEAKENING IN NORTHERLY
FLOW THROUGH THE PERIOD...WITH NEAR SCEC FOR THE OFFSHORE GULF OF
MEXICO TODAY. OFFSHORE WINDS EXPECTED TO BE LIGHT BY LATE SATURDAY
WITH HIGH PRESSURE NEAR THE COAST. OTHER THAN LIGHT RAIN...SEE NO
OTHER SIGNIFICANT MARINE ISSUES.
&&
.LONG-TERM (SATURDAY NIGHT THROUGH THURSDAY NIGHT)...THE EXITING
UPPER LOW WILL ALLOW FOR BRIEF RIDGING ALOFT BY THE LATTER HALF OF
THE WEEKEND WITH SURFACE HIGH BEGINNING TO SHIFT EAST AHEAD OF THE
NEXT UPPER TROUGH. MODELS CONTINUE TO SWING THE UPPER TROUGH EAST AS
IT DIGS ACROSS THE FOUR CORNERS REGION EARLY NEXT WEEK. AGREEMENT
REMAINS WITH THE TIMING OF THE ASSOCIATED COLD FRONT REACHING SOUTH
TEXAS LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. MOISTURE RETURN
AHEAD OF THE FRONT IS NOT ALL GREAT FOR RAIN CHANCES. HOWEVER
MOISTURE MAY BE ENOUGH ACROSS THE WATERS TO ALLOW FOR ISOLATED
SHOWERS. THE 1040MB HIGH COMING OUT OF CANADA IS EXPECTED TO WEAKEN
A BIT BEFORE REACHING SOUTH TEXAS...MODIFYING EVER SO SLIGHTLY THE
COLD AIRMASS. WITH THIS SAID...DAYTIME TEMPERATURES ARE STILL
EXPECTED TO FALL AND RANGE IN THE 50S MONDAY. CLEARING MONDAY NIGHT
SHOULD LEAD COLD TEMPERATURES MONDAY NIGHT WITH LOWS IN THE 30S WITH
LOCATIONS ACROSS THE NORTHERN CWA REACHING NEAR FREEZING. BY
MIDWEEK...MODELS BEGIN TO DIVERGE WITH SOLUTIONS AS THE EUROPEAN
BREAKS OFF A LOW FROM THE EXITING TROUGH...WHILE THE GFS GENERATES
WEAK MID LEVEL RIDGING. HOWEVER AT THE SURFACE...BOTH SHIFT THE
SURFACE HIGH EAST WITH ONSHORE FLOW REDEVELOPING BRINGING MOISTURE
BACK TO THE REGION. WITH THE ADDITIONAL UPPER SUPPORT...THE EUROPEAN
APPEARS TO BE THE WETTER SOLUTION. HOWEVER TO KEEP SOME CONSISTENCY
UNTIL FURTHER AGREEMENT UPON MODELS...WILL MAINTAIN A MOSTLY DRY
FORECAST WITH ONLY SLIGHT CHANCES FOR LIGHT RAIN WED/THURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 57 46 63 44 69 / 70 20 20 10 10
VICTORIA 61 40 63 41 68 / 40 10 10 10 10
LAREDO 55 47 64 46 70 / 70 20 10 10 10
ALICE 58 45 65 42 69 / 70 20 20 10 10
ROCKPORT 61 46 62 46 65 / 60 10 20 10 10
COTULLA 55 45 64 42 68 / 50 20 10 10 10
KINGSVILLE 57 44 63 42 70 / 70 20 20 10 10
NAVY CORPUS 59 49 62 47 67 / 70 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 950 PM CST THU DEC 26 2013
SKY FORECAST IS EXTREMELY PROBLEMATIC...RESULTING FROM THE LARGE
CLEARING HOLE THAT HAS DEVELOPED IN CENTRAL MINNESOTA. OVERALL
THERE IS A GENERAL WESTERLY WIND FLOW...WHICH IS ALLOWING THE
CURRENT HIGHER BASED STRATUS OVER THE FORECAST AREA TO PUSH OFF TO
THE EAST. SO IT SEEMS THERE SHOULD BE CLEARING OVER THE NEXT FEW
HOURS BEHIND THIS HIGHER BASED STRATUS. MEANWHILE...THAT SAME
WESTERLY FLOW IS ALLOWING SOME ADVANCEMENT EASTWARD OF THE LOW
STRATUS IN WESTERN AND SOUTH CENTRAL MN. HOWEVER...THAT HOLE
THAT IS IN CENTRAL MINNESOTA IS EXPANDING. NAM/RAP LOW LEVEL RH
PROGS DO NOT HAVE A GOOD HANDLE ON THE SITUATION...BUT SPECIFIC
VALUES WOULD SEEM TO SUGGEST THAT THE STRATUS COMING AT US FROM
WESTERN MN WILL DISSIPATE SOME. AGAIN...NEEDLESS TO SAY A TOUGH
SKY FORECAST.
ON TOP OF THE SKY PROBLEM...IN THAT CLEARING HOLE VISIBILITIES
HAVE DROPPED IN SOME SPOTS TO 1/4 MILE. THIS COULD HAPPEN AS WELL
OVER THE FORECAST AREA WHEN SKIES CLEAR. HAVE INCLUDED PATCHY FOG
OVERNIGHT...BUT WOULD NOT BE SURPRISED IF THIS FOG NEEDS TO BE
EXPANDED IN COVERAGE. THERE IS EVEN AN OUTSIDE CHANCE OF A DENSE
FOG ADVISORY NEED IF SKIES CAN STAY CLEAR.
ON A FINAL NOTE...THE SNOW THAT BECAME ENHANCED A BIT ALONG I-94
IS DIMINISHING...RESULTING FROM A SHORTWAVE PASSAGE ON WATER VAPOR
AND ISENTROPIC DESCENT OCCURRING ON THE 270-275K SURFACES.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1132 PM CST THU DEC 26 2013
FOG/MIST REMAINS THE MAIN CONCERN FOR THE TAFS...PARTICULARLY FOR
THIS MORNING. SKIES HAVE CLEARED OUT OVER CENTRAL MINNESOTA AND
THIS CLEARING IS APPROACHING THE TAF SITES. ANTICIPATING BOTH
SITES TO BE CLEAR BY 07Z. THIS CLEARING COMBINED WITH LIGHT WINDS
AND MOISTURE AT THE SURFACE HAS RESULTED IN VARIABLE FOG/MIST
ACROSS CENTRAL MN. VISIBILITIES THERE RANGE FROM VLIFR TO VFR.
BELIEVE SOMETHING SIMILAR WILL HAPPEN AT THE TAF SITES...SO PUT
FOR NOW A RANGE OF MVFR TO IFR. VLIFR CONDITIONS ARE POSSIBLE AS
WELL...BUT CONFIDENCE IS TOO LOW RIGHT NOW TO INCLUDE. THERE ARE
HIGHER CLOUDS DROPPING SOUTH THROUGH MN...AND THESE CLOUDS
COMBINED WITH SOUTHWEST WINDS PICKING UP AROUND 13Z SHOULD HELP TO
GET RID OF ANY FOG/MIST.
OTHERWISE...VFR CONDITIONS ARE ANTICIPATED THROUGH 06Z FRIDAY
NIGHT. THE ONLY OTHER HIGHLIGHT IS WINDS THIS AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS. WINDS AT RST LOOK TO COME UP TO 15-20
KT WITH SLIGHTLY HIGHER GUSTS...WHILE ONLY COMING UP TO 10-15 KT
AT LSE. A STRONG WIND CORE COMING ACROSS THE TAF SITES BETWEEN
19-23Z RESULTS IN THE NEED FOR LOW LEVEL WIND SHEAR AT LSE. THE
WIND DIFFERENCE IS NOT HIGH ENOUGH TO MENTION AT RST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1035 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
HIGH PRESSURE CENTERED TO THE SOUTHWEST IS PROVIDING DRY WEATHER
FOR SOUTHERN NEW ENGLAND. MADE ADJUSTMENTS TO TEMPS/DEWPOINTS
BASED ON LATEST OBSERVED TRENDS. TWEAKED SKY COVER UP SLIGHTLY
ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND BASED ON VISIBLE
SATELLITE DATA...BUT NO SIGNIFICANT CHANGES TO FORECAST.
PREVIOUS DISCUSSION...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY- SUBSIDENCE INVERSION
ACROSS THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS
FROM GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH
THE AFOREMENTIONED INVERSION AS WEAK MID- LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE...UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN
OPEN RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST
THROUGH QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS
THROUGH NEW ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS
MOVES THROUGH WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR
WEST THROUGH MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY
NIGHT. THIS CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY
WITH A SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS
DOES MOVE THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND
BURST OF COLD AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE
NOTICE THE DIFFERENCE?
MODELS...THERE IS GENERAL AGREEMENT ON THE PATTERN BUT
DIFFERENCES IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL
STORM ON SUNDAY. THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST
WITH THE STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE
ECMWF IS FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY
SNOW OR A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A
BLEND OF MODEL VALUES.
THE DAILIES...
SUNDAY...SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT
OUTSIDE CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE
MAINLY AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO
THIS LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A
LITTLE COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND
COULD SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND
1 AM MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND
BRING COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD
OF SNOW MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY...NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND.
BUT WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A
TRANSITION DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE
AFTERNOON. THIS WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS
ALOFT WILL CENTER AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN
THE 30S AND LOWER 40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY...ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE
EQUIVILENT TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE
TEMPS SHOULD BE ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE
NUMBERS EITHER SIDE OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE
SINGLE NUMBERS AND POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
1030 AM UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. CLOUDS CLEAR OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY...MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/WTB
NEAR TERM...BELK/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...BELK/SIPPRELL/WTB
MARINE...SIPPRELL/WTB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
625 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630 AM UPDATE...
HIGH PRESSURE CENTERED TO THE SOUTHWEST IS PROVIDING DRY WEATHER
FOR SOUTHERN NEW ENGLAND. MADE ADJUSTMENTS TO TEMPS/DEWPOINTS
BASED ON 6 AM OBS...BUT NO SIGNIFICANT CHANGES TO FORECAST.
PREVIOUS DISCUSSION...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY- SUBSIDENCE INVERSION
ACROSS THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS
FROM GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH
THE AFOREMENTIONED INVERSION AS WEAK MID- LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE... UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN OPEN
RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST THROUGH
QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS THROUGH NEW
ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS MOVES THROUGH
WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR WEST THROUGH
MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY NIGHT. THIS
CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY WITH A
SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS DOES MOVE
THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND BURST OF COLD
AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE NOTICE THE DIFFERENCE?
MODELS... THERE IS GENERAL AGREEMENT ON THE PATTERN BUT DIFFERENCES
IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL STORM ON SUNDAY.
THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST WITH THE
STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE ECMWF IS
FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY SNOW OR
A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A BLEND OF
MODEL VALUES.
THE DAILIES...
SUNDAY... SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT OUTSIDE
CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE MAINLY
AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO THIS
LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A LITTLE
COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND COULD
SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND 1 AM
MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND BRING
COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD OF SNOW
MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY... NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND. BUT
WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A TRANSITION
DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE AFTERNOON. THIS
WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS ALOFT WILL CENTER
AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN THE 30S AND LOWER
40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY... ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE EQUIVILENT
TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE TEMPS SHOULD BE
ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE NUMBERS EITHER SIDE
OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE SINGLE NUMBERS AND
POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
630 AM UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
640 AM EST Fri Dec 27 2013
Updated aviation discussion.
.NEAR TERM [Today and Tonight]...
Early morning surface analysis reveals the forecast area locked in
northeasterly flow with an approximately 1030mb high pressure
centered to the north and west (Arklatex to Kentucky). This
surface flow pattern exists up the east coast, and over much of
the Gulf of Mexico. Higher thetae air is displaced well to the
south over south Florida and the southern Gulf of Mexico.
Meanwhile, the weather over our forecast area is relatively
unchanged from the past 12-24 hours with cloudy, cool conditions
and some intermittent very light rain showers. This should
continue during the day today with a mixture of low and mid level
cloud decks. RAP analysis shows a significant 850mb dewpoint
gradient bisecting our area from SW-NE (roughly from PAM-FZG).
This is confirmed by comparing the 00z sounding from TAE with ones
to the north and west (LIX, BMX, FFC). Therefore, the southeastern
half of our area is situated in a region of greater low-level
moisture. This is where some light rain showers or patchy drizzle
will be possible today. Some weak isentropic ascent is forecast in
the 290-295K planes; the ascending flow in these layers is only
around 5-10 knots so the forcing should be fairly limited.
However, the forcing should be sufficient for drizzle or light
showers, and this is confirmed by some weak returns on the TLH
radar over the past few hours. The isentropic ascent should both
deepen and increase overnight as wind fields increase - and this
is when rain showers should spread into much of the forecast area.
.SHORT TERM [Saturday through Sunday]...
Fairly active weather pattern stetting up for the weekend as an
upper low evolving over nrn Mexico/SW TX today ejects enewd across
the central Gulf coast states/sern US this weekend as a
deamplifying trough. Ahead of this system, responding sly low
level winds across the Gulf coast/ern GoM this weekend will
increase low level WAA/ascent and bring both an increase in clouds
and rising PoPs Saturday and Sunday. Rain showers are expected to
develop over the wrn counties Saturday into Saturday night,
spreading ewd across remainder of the area into Sunday. This will
keep things seasonably cool/wet Saturday over sern AL, inland
parts of the FL panhandle into swrn GA. This system will be fast
moving so rain totals are expected to be around 1-1.5 inches over
most areas. Sunday should see fairly steady improvements with rain
chances ending from west to east through the day. Given the expect
cool air and little time for recovery, expect thunderstorms will
remain most likely over the Gulf of Mexico. However will include
slgt chance or chance of tstms spreading inland Saturday afternoon
into Sunday as warm sector becomes better defined over the nern
Gulf. Overall risk of severe storms appears fairly low attm given
the expected limited instability. Regardless, increasing low and
deep layer shear suggest an isolated strong to severe storm
remains possible.
.LONG TERM [Sunday Night Through Friday]...
The extended period begins with a cold front pushing through the
Tri-state region with rain ending from west to east Sunday. This
will be quickly followed by a dry cold front Monday as an amplifying
upper trough over the nation`s midsection moves east. In its wake,
we can expect at least two more days with cooler and dry weather.
Wednesday night through Thursday, cyclogenesis is forecast to
develop along the Central Gulf coast in response to the next
shortwave dropping down into the Southern plains. The surface low
with this system is currently forecast to be rather weak and pass
over or south of our coastal waters. For now, will just introduce
slight PoPs for all zones for Thursday. Temps will be at or below
seasonal levels through the period.
&&
.AVIATION...
[Through 12Z Saturday] Ceilings will remain today, but should be
mostly of the VFR variety. There will be a better chance for MVFR
CIGS overnight, mainly after 03z and at ECP, TLH, and VLD. Some -DZ
and -SHRA will affect TLH and VLD through around 19-20z, before a
brief lull in the late afternoon. -SHRA should begin to spread over
much of the area overnight, but significant visibility restrictions
are not expected.
&&
.MARINE...
Northeast winds will remain at cautionary levels today and
tonight, and hold in the 15-20 kt range Saturday as winds switch
to a more easterly direction and rain chances increase. By
Saturday night into Sunday winds will become more out of the
southeast and increase over wrn legs to near advisory criteria as
a surface low moves into the FL panhandle. Winds and seas are
expected to subside early next week.
&&
.FIRE WEATHER...
Relative humidity will remain well above critical thresholds.
Therefore, red flag conditions are not expected. Wetting rains are
likely this weekend.
&&
.HYDROLOGY...
The Apalachicola River at Blountstown is expected to remain in
minor flood stage through the weekend with releases from
Woodruff Dam. The Kinchafoonee Creek`s crest near Dawson is
forecast to just barely reach minor flood stage early Friday
morning and drop below minor flood stage on Friday evening. The
Choctawhatchee River at Caryville is expected to barely reach
minor flood stage on Friday morning and drop below minor flood
stage Saturday morning.
Early projections on rainfall this weekend are in the 1-2" range.
This should help to keep river levels elevated.
&&
.PRELIMINARY POINT TEMPS/POP...
Tallahassee 60 48 66 58 69 / 20 30 50 70 50
Panama City 61 50 63 58 65 / 20 50 60 80 40
Dothan 59 45 57 49 62 / 10 30 70 80 40
Albany 58 42 58 51 66 / 10 20 60 80 50
Valdosta 58 45 67 57 70 / 20 30 50 70 60
Cross City 64 51 73 61 73 / 30 30 40 60 60
Apalachicola 62 52 67 59 68 / 30 40 50 70 50
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Evans
LONG TERM...Barry
AVIATION...Lamers
MARINE...Evans
FIRE WEATHER...Lamers
HYDROLOGY...DVD/McDermott
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
539 AM CST FRI DEC 27 2013
.DISCUSSION...SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...FOR THE MOST PART...WILL HAVE VFR CIGS FOR THE
DAY...WITH TEMPO MVFR CIGS AND/OR VSBYS WHERE THE RAIN WILL BE
HEAVIER AT TIMES. MOST OF THE RAINFALL SHOULD END BETWEEN 18Z-
22Z...WITH ONLY PATCHY LIGHT RAIN FOR THE REMAINDER OF THE
TERMINAL FORECAST (AND THUS WILL NOT MENTION THIS IN THE
TERMINALS). AM EXPECTING CIGS TO REMAIN VFR OR BETTER AFTER SUNSET
EXCEPT AT KRLD WHERE LIFR CIGS ARE EXPECTED AOA 06Z. WITH LIGHT
NORTH WINDS OVERNIGHT...MAY SEE SOME BR AT KVCT (HAVING IT THIS
MORNING)...BUT SHOULD BE NO WORSE THAN MVFR. NOT EXPECTING FOG AT
KALI OR KCRP. WINDS THOUGH THE PERIOD OVERALL AT ALL TERMINALS
SHOULD BE BELOW 11 KNOTS...ALTHOUGH COULD NOT RULE OUT A BIT
HIGHER WINDS AT KCRP THIS MORNING IF NORTHEAST WINDS REMAIN.
&&
.PREV DISCUSSION... /ISSUED 347 AM CST FRI DEC 27 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...RAIN IS OCCURRING OVER MUCH
OF THE CWA...AND THIS SHOULD CONTINUE THROUGH ABOUT MID MORNING
BEFORE IT BEGINS TO TAPER OFF. HRRR MODEL SHOWING WIDESPREAD LIGHT
RAIN THROUGH ABOUT 15Z...THEN TAPERING OFF LATE IN THE MORNING. THIS
RAIN IS DUE TO UPPER SUPPORT IN THE FORM OF RRQ OF JET AND Q-VECTOR
CONVERGENCE...BOTH OF WHICH WILL BE LESS OF A FACTOR BY THIS EVENING
(SOME WEAK UPGLIDE AS WELL). GUIDANCE IS GOING CHANCE TO LIKELY
POPS...AND SEE NO NEED TO QUARREL WITH THIS. WOULD BE TEMPTED TO GO
EVEN A BIT HIGHER ON POPS SOME AREAS BUT RAIN COULD END OVER SOME
AREAS SHORTLY AFTER 12Z WHEN FORECAST BEGINS. WITH RAIN CHANCES
DIMINISHING BY MID AFTERNOON...AM GOING WITH SLIGHT CHANCE POPS
NORTHEAST (SOME DRY AIR MOVING IN)...WITH CHANCE POPS FARTHER WEST.
RAIN AND CLOUD COVER SHOULD KEEP TEMPERATURES DOWN AGAIN TODAY...AND
AM GOING ON THE LOW SIDE OF GUIDANCE. FOR TONIGHT...MEASURABLE RAIN
SHOULD BE ISOLATED AT BEST WITH RRQ EXITING. HOWEVER...COULD BE WEAK
UPGLIDE WESTERN AREAS TONIGHT AND SOME POSSIBLE LFQ JET DYNAMICS.
FOR SATURDAY...LIGHT RAIN (IF ANY) SHOULD BE RESTRICTED TO THE
COASTAL COUNTIES (AND OFFSHORE) WITH WEAK MOISTURE ADVECTION AND
SOME WEAK DYNAMICS ALOFT. COULD SEE SOME CLEARING SATURDAY
AFTERNOON...SO AM GOING TO GO A BIT WARMER ON THE FORECAST.
MARINE (TODAY THROUGH SATURDAY)...GRADUAL WEAKENING IN NORTHERLY
FLOW THROUGH THE PERIOD...WITH NEAR SCEC FOR THE OFFSHORE GULF OF
MEXICO TODAY. OFFSHORE WINDS EXPECTED TO BE LIGHT BY LATE SATURDAY
WITH HIGH PRESSURE NEAR THE COAST. OTHER THAN LIGHT RAIN...SEE NO
OTHER SIGNIFICANT MARINE ISSUES.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY NIGHT)...THE EXITING
UPPER LOW WILL ALLOW FOR BRIEF RIDGING ALOFT BY THE LATTER HALF OF
THE WEEKEND WITH SURFACE HIGH BEGINNING TO SHIFT EAST AHEAD OF THE
NEXT UPPER TROUGH. MODELS CONTINUE TO SWING THE UPPER TROUGH EAST AS
IT DIGS ACROSS THE FOUR CORNERS REGION EARLY NEXT WEEK. AGREEMENT
REMAINS WITH THE TIMING OF THE ASSOCIATED COLD FRONT REACHING SOUTH
TEXAS LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. MOISTURE RETURN
AHEAD OF THE FRONT IS NOT ALL GREAT FOR RAIN CHANCES. HOWEVER
MOISTURE MAY BE ENOUGH ACROSS THE WATERS TO ALLOW FOR ISOLATED
SHOWERS. THE 1040MB HIGH COMING OUT OF CANADA IS EXPECTED TO WEAKEN
A BIT BEFORE REACHING SOUTH TEXAS...MODIFYING EVER SO SLIGHTLY THE
COLD AIRMASS. WITH THIS SAID...DAYTIME TEMPERATURES ARE STILL
EXPECTED TO FALL AND RANGE IN THE 50S MONDAY. CLEARING MONDAY NIGHT
SHOULD LEAD COLD TEMPERATURES MONDAY NIGHT WITH LOWS IN THE 30S WITH
LOCATIONS ACROSS THE NORTHERN CWA REACHING NEAR FREEZING. BY
MIDWEEK...MODELS BEGIN TO DIVERGE WITH SOLUTIONS AS THE EUROPEAN
BREAKS OFF A LOW FROM THE EXITING TROUGH...WHILE THE GFS GENERATES
WEAK MID LEVEL RIDGING. HOWEVER AT THE SURFACE...BOTH SHIFT THE
SURFACE HIGH EAST WITH ONSHORE FLOW REDEVELOPING BRINGING MOISTURE
BACK TO THE REGION. WITH THE ADDITIONAL UPPER SUPPORT...THE EUROPEAN
APPEARS TO BE THE WETTER SOLUTION. HOWEVER TO KEEP SOME CONSISTENCY
UNTIL FURTHER AGREEMENT UPON MODELS...WILL MAINTAIN A MOSTLY DRY
FORECAST WITH ONLY SLIGHT CHANCES FOR LIGHT RAIN WED/THURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 57 46 63 44 69 / 70 20 20 10 10
VICTORIA 61 40 63 41 68 / 40 10 10 10 10
LAREDO 55 47 64 46 70 / 70 20 10 10 10
ALICE 58 45 65 42 69 / 70 20 20 10 10
ROCKPORT 61 46 62 46 65 / 60 10 20 10 10
COTULLA 55 45 64 42 68 / 50 20 10 10 10
KINGSVILLE 57 44 63 42 70 / 70 20 20 10 10
NAVY CORPUS 59 49 62 47 67 / 70 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS RENO NV
211 PM PST FRI DEC 27 2013
.SYNOPSIS...
AREAS OF FOG AND LOW CLOUDS WILL PERSIST TONIGHT IN SOME LOWER
ELEVATION VALLEYS. OTHERWISE WEAK LOW PRESSURE WILL JUST BRING HIGH
CLOUDS THROUGH SATURDAY. WINDS MAY KICK UP ENOUGH TO MIX OUT SOME
VALLEY INVERSIONS SATURDAY, AND GUSTY NORTHEAST WINDS ARE LIKELY IN
THE SIERRA SATURDAY NIGHT. HIGH PRESSURE WILL BUILD BACK INTO THE
REGION NEXT WEEK WITH NO BIG STORMS ON THE HORIZON.
&&
.SHORT TERM...
FOG AND LOW CLOUDS HAVE PERSISTED EAST OF SUSANVILLE AND NEAR
FALLON/LOVELOCK TODAY. HRRR GUIDANCE, WHICH PICKED UP ON FOG NEAR
FALLON, SUGGESTS IT WILL CONTINUE INTO THE EVENING HOURS IN THE NFL
AND CARSON SINK AREAS. HOWEVER FORECAST SOUNDINGS SHOW DRY AIR
MIXING INTO THE LOW LEVELS WHICH ALONG WITH SLIGHTLY INCREASED WINDS
MAY BE ENOUGH TO ERODE FOG/STRATUS. ADMITTEDLY FORECAST
CONFIDENCE IN FOG TRENDS IS ONLY MEDIUM - IT`S ALWAYS A TRICKY
THING TO FORECAST. BASED ON RECENT IMPROVING TRENDS IN VISIBILITY
AT LOL/NFL I`LL CANCEL THE FREEZING FOG ADVISORY, BUT IT IS NOT
OUT OF THE QUESTION WE MAY NEED TO REISSUE LATER THIS EVENING.
ELSEWHERE PATCHY FOG AND LOW CLOUDS ARE POSSIBLE, BUT REDEVELOPMENT
WILL BE LIMITED BY HIGH CLOUDS AHEAD OF APPROACHING SHORTWAVE. THAT
WAVE MAY KICK UP THE WINDS ENOUGH TO MIX OUT INVERSIONS IN ALL BUT
THE LOWEST VALLEYS ON SATURDAY. BEHIND THE WAVE, FLOW ALOFT TURNS NE
AND STRENGTHENS, LEADING TO A PERIOD OF GUSTY WINDS IN THE SIERRA
SATURDAY NIGHT. RIDGE BUILDS BACK IN STARTING SUNDAY, PROBABLY
LEADING TO MORE INVERSIONS AND HAZY CONDITIONS FOR THE VALLEYS EARLY
NEXT WEEK. GFS SHOWS LIGHT PRECIP ALONG THE NV/OR BORDER ASSOCIATED
WITH A PASSING JET STREAK MONDAY NIGHT. CONFIDENCE IN WHETHER THIS
PRECIP WILL IMPACT OUR CWA IS LOW, SO HAVE CONTINUED DRY FORECAST. CS
&&
.LONG TERM...TUESDAY THROUGH FRIDAY...
DRY PATTERN WITH LIGHT WINDS AND INVERSION CONDITIONS IS EXPECTED TO
PREVAIL THROUGH NEXT FRIDAY. THE LATEST GFS SHOWS THE RIDGE IN
CLOSER PROXIMITY TO WESTERN NV WHICH WOULD RESULT IN REDUCED
COVERAGE OF CIRRUS ESPECIALLY FOR THURS-FRI. THE ECMWF IS A LITTLE
FLATTER WITH THE RIDGE AND SPREADS HIGH LEVEL MOISTURE OVER THE
REGION AT TIMES, ESPECIALLY NORTH OF I-80. THE ECMWF ALSO BRUSHES A
WEAK SHORTWAVE ACROSS THE FAR NORTH BY NEXT FRIDAY EVENING, BUT
THESE FEATURES HAVE VARIED IN TIMING AND LOCATION WITH EACH RUN SO
WILL NOT ADD ANY PRECIP AT THIS TIME. MAX TEMPS SHOULD REMAIN NEAR
50 DEGREES THRU MOST OF NEXT WEEK. THE INVERSION APPEARS WEAKER ON
TUESDAY SO LOWER ELEVATIONS MAY BE A FEW DEGREES WARMER, OTHERWISE
LITTLE VARIATION IS EXPECTED WITH DAYTIME HIGHS BETWEEN WESTERN NV
AND THE SIERRA VALLEYS. MIN TEMPS WILL BE NEAR SEASONAL NORMALS
MAINLY IN THE LOWER-MID 20S FOR URBAN AREAS, AND TEENS FOR THE
TYPICALLY COOLER VALLEYS IN WESTERN NV AND NEAR THE SIERRA.
FOR THE FOLLOWING WEEK, THE GFS AND SOME OF ITS ENSEMBLE MEMBERS
ATTEMPT TO BREAK DOWN THE PERSISTENT RIDGE NEAR THE WEST COAST,
WITH A FEED OF PACIFIC MOISTURE REACHING THE SIERRA ROUGHLY BETWEEN
JANUARY 7 AND 11. SINCE THESE PROJECTIONS ARE SO FAR INTO THE FUTURE
AND THE ECMWF DOES NOT YET RUN INTO THIS TIME FRAME, THE CONFIDENCE
IN SEEING A CHANGE TO A WETTER PATTERN FOR EASTERN CA-WESTERN NV IS
STILL LOW. MJD
&&
.AVIATION...
AT THE MAIN TERMINALS, VFR CONDITIONS WILL PREVAIL THROUGH THIS
WEEKEND AS THE SHORTWAVE PASSAGE TONIGHT SHOULD PREVENT
REDEVELOPMENT OF FREEZING FOG. WINDS WILL GENERALLY REMAIN 10 KT OR
LESS.
A FEW STUBBORN AREAS OF LOW CLOUDS AND FZFG PRODUCING IFR/LIFR CIGS
AND/OR VSBY WILL BE SLOW TO DISSIPATE TONIGHT IN EASTERN LASSEN
COUNTY AFFECTING KSVE, EXTENDING EASTWARD ACROSS THE SMOKE CREEK
DESERT TO NEAR GERLACH. ALSO IMPACTED WILL BE THE WEST CENTRAL NV
BASIN INCLUDING KLOL AND KNFL. SOME LOCATIONS, ESPECIALLY IN
CHURCHILL COUNTY, MAY NOT CLEAR OUT UNTIL MIDDAY SATURDAY. MJD
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
954 AM MST FRI DEC 27 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOK REASONABLE. UPPER RIDGE
BUILDING ACROSS GREAT BASIN INTO COLORADO. SOME MID AND HIGH LEVEL
MOISTURE OVER COLORADO AS VERY WEAK MID LEVEL WAVE MOVES INTO
CENTRAL PLAINS. TEMPERATURES WARMING NICELY AS MOST AREAS ACROSS
PLAINS IN THE 40S HEADING TO THE MIDDLE 50S. FLOW ALOFT BECOMES
WESTERLY TONIGHT AHEAD OF APPROACHING TROUGH. WINDS TO INCREASE
ACROSS MOUNTAINS AND FOOTHILLS...PERHAPS SOME GUSTS TO 40 MPH.
.AVIATION...CURRENT TAF TRENDS LOOK REASONABLE. LATEST RAP AND
HRRR SHOW WINDS SHIFTING TO THE NORTH BY 18Z...THEN CLOCKWISE TO
THE SOUTHEAST THROUGH THE AFTERNOON. BASED ON CURRENT WIND AND
PRESSURE PATTERN ACROSS THE AREA...WOULD EXPECT WINDS TO STAY
SOUTHERLY THROUGH THE DAY. DRAINAGE TO THEN DEVELOP DURING THE
EVENING. VFR TO CONTINUE THROUGH SATURDAY. COLD FRONT EXPECTED TO
MOVE ACROSS THE AREA AROUND 19Z WITH GUSTY NORTHERLY WINDS. SOME
INCREASE IN MID AND HIGH LEVEL MOISTURE...WITH LOWER CEILINGS NOT
EXPECTED UNTIL AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 328 AM MST FRI DEC 27 2013/
SHORT TERM...WATER VAPOR IMAGERY SHOWING BROAD RIDGE ALOFT
BUILDING ACROSS MUCH OF THE GREAT BASIN WITH RISING HEIGHTS AND
WARMING TEMPERATURES. 700MB TEMPERATURES EXPECTED TO RISE AROUND
+3C TODAY OVER NORTHEAST COLORADO WHICH WILL RESULT IN TEMPERATURES
ABOUT 3-6 DEGREES OF WARMING THIS AFTERNOON. THERE IS SOME HIGH
LEVEL MOISTURE OVER WYOMING WHICH WILL DRIFT OVER NORTHERN
COLORADO THIS MORNING BUT WON`T HAVE MUCH EFFECT ON THE OVERALL
FORECAST. AS THE FLOW ALOFT SHIFTS MORE WESTERLY TONIGHT SHOULD
SEE SOME GUSTY WINDS IN THE 25-40 MPH RANGE INCREASE OVER THE
MOUNTAINS AND EAST SLOPES AFTER MIDNIGHT TONIGHT.
LONG TERM...AN UPPER TROUGH WILL PUSH ITS WAY SOUTHEAST OVER THE
STATE SATURDAY. ITS ASSOCIATED COLD FRONT IS EXPECTED TO MOVE
THROUGH DURING THE DAYTIME SO HIGH TEMPERATURES THAT DAY WILL
LIKELY HAPPEN EARLY ON...ESPECIALLY IN THE NORTH. LIGHT SNOW IS
EXPECTED OVER THE MOUNTAINS DURING THE AFTERNOON...THEN UPSLOPE
FLOW FOLLOWING THE FRONT AND QG VERTICAL LIFT OVERHEAD WILL ALLOW
FOR A CHANCE OF SNOW OVER THE FOOTHILLS AND PLAINS OVERNIGHT. NOT
MUCH QPF EXPECTED WITH THIS SYSTEM...UP TO A COUPLE INCHES OVER
THE MOUNTAINS AND LIKELY LESS THAN A HALF INCH OVER THE PLAINS.
WARMER TEMPERATURES TODAY AND TOMORROW BEFORE THE FRONT WILL
LIKELY HINDER MUCH ACCUMULATION ON THE GROUND OVER THE FOOTHILLS
AND PLAINS. A STRONG PRESSURE GRADIENT ASSOCIATED WITH THE FRONT
WILL BRING NORTH WINDS BEHIND THE FRONT OVER THE EASTERN PLAINS
OF 15 TO 25 MPH SUSTAINED WITH POSSIBLE GUSTS TO 35 MPH.
TEMPERATURES WILL DROP INTO THE TEENS OVERNIGHT OVER THE PLAINS
AND IN THE SINGLE DIGITS OVER THE MOUNTAINS.
SUNDAY`S TEMPERATURES WILL BE 10 TO 20 DEGREES COOLER THAN
SATURDAY WITH 30S OVER THE PLAINS AND 20S FOR THE MOUNTAINS. SNOW
SHOULD BE DONE BY MID MORNING OVER THE PLAINS BUT LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS AS A 125+KT JET IN NORTHWEST FLOW
ALOFT MOVES OVERHEAD.
A SHORTWAVE RIDGE WILL MOVE OVERHEAD MONDAY TO BRING WARMER
TEMPERATURES AND A DRY PERIOD FOR THE MOUNTAINS BEFORE THE NEXT
SYSTEM MOVES IN FOR TUESDAY. TEMPERATURES WILL LIKELY BE WARMER
TUESDAY AS THE SYSTEM CREATES DOWNSLOPING OVER THE LEESIDE OF THE
CO ROCKIES. SOME SNOW FOR THE HIGH COUNTRY...BUT LIKELY NOTHING
FOR THE PLAINS EXCEPT PERHAPS FOR THE FAR NORTHEASTERN CORNER.
MOST OF THE COLD AIR WILL BE EXPECTED TO AFFECT CO FOR WEDNESDAY
BUT WILL LIKELY ONLY COOL TEMPERATURES BY A FEW DEGREES. WILL HAVE
TO WATCH TO SEE IF MODELS DIG THIS SYSTEM DEEPER HOWEVER. THE WEST
COAST UPPER RIDGE SHOULD BUILD IN THURSDAY FOR WARMER AND DRIER
WEATHER.
AVIATION...VFR WITH ONLY SCATTERED TO BROKEN CIRRUS CLOUDS FOR
MAINLY THIS MORNING. SOUTH TO SOUTHWEST DRAINAGE WINDS WILL SHIFT
A BIT MORE SOUTHEAST THIS AFTERNOON BUT SPEEDS WILL GENERALLY BE
UNDER 15KT. WITH DECREASING WINDS ALOFT SHOULD BE A SMOOTH FLYING
DAY OVER THE REGION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
508 PM EST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF ACROSS
THE UPR GRT LKS BTWN TROFFING OVER ERN NAMERICA AND UPR RDG IN THE
ROCKIES. SW FLOW/ISENTROPIC ASCENT IN ADVANCE OF SHRTWV DIGGING SEWD
THRU ONTARIO HAS BROUGHT LOTS OF CLDS TO THE CWA. RADAR/SFC OBS
INDICATE SN IS FALLING OVER LK SUP CLOSER TO THE SHARPER ISENTROPIC
ASCENT/SHRTWV AND ACCOMPANYING SFC LO TRACK...BUT DRY WEDGE BTWN
H8-7 SHOWN ON THE 12Z INL RAOB HAS LIMITED THE COVERAGE OF THE SN
FARTHER SW OVER THE LAND CWA. OTRW...SSW LLVL FLOW HAS ADVECTED
WARMER AIR INTO UPR MI...WITH TEMPS THIS AFTN APRCHG ABV 32 AT IWD.
BUT TEMPS REMAIN WELL BLO FRZG OVER THE INTERIOR CENTRAL. THERE IS
SOME CLRG IN MN EXTENDING TOWARD WRN UPR MI WHERE THE LLVL WARMING
HAS BEEN MOST AGGRESSIVE ON THE SRN FLANK OF THE SFC LO SHIFTING
ESEWD NEAR THE MN/CNDN BORDER AND IN ADVANCE OF AN ATTENDANT LO PRES
TROF EXTENDING SWWD INTO THE ERN DAKOTAS. BUT MORE LO CLDS AND SOME
GUSTY NW WINDS FOLLOW THIS TROF FM NDAKOTA INTO MANITOBA/ADJOINING
ONTARIO. FARTHER TO THE W...A STRONG SHRTWV IS MOVING OVER THE WRN
UPR RDG INTO THE PAC NW/BRITISH COLUMBA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/POPS THIS AFTN
RELATED TO THE ONGOING WAD AHEAD OF THE APRCHG DISTURBANCE AND THEN
THE CHC FOR SOME -SN OR EVEN FREEZING DRIZZLE TNGT INTO SAT
FOLLOWING THE TROF PASSAGE.
LATE THIS AFTN/TNGT...BEST CHC FOR SOME WAD SN LATE THIS AFTN INTO
THE EVNG WL BE OVER THE ERN CWA WHERE GUIDANCE SHOWS DEEPER
SATURATION UNDER THE SHARPER ISENROPIC ASCENT DEEPER INTO THE
RETREATING COLD AIR. THE CHC POPS OVER THE ERN CWA WL SHIFT TO THE E
THIS EVNG FOLLOWING PASSAGE OF DISTURBANCE AND END OF WAD/ISENTROPIC
ASCENT. ALTHOUGH THERE WL BE SOME CLRG OVER THE W LATE THIS AFTN
INTO EARLY EVNG PER CURRENT OBS/STLT TRENDS...PASSAGE OF SFC LO PRES
TROF WL BRING A RETURN OF MORE LLVL MSTR/LO CLDS. SOME OF THE MODELS
ALSO GENERATE LGT PCPN OVER MAINLY THE W IN AREAS WHERE WNW FLOW WL
UPSLOPE DESPITE PRESENCE OF LARGER SCALE QVECTOR DVGC/DNVA/WEAK CAD
FOLLOWING THE SHRTWV. FCST SDNGS INDICATE THE MSTR WL BE CONFINED TO
THE LOWEST FEW THOUSAND FEET AND WELL BLO THE DGZ AS INCOMING
AIRMASS IS MARITIME POLAR IN ORIGIN. IN FACT...H85 TEMPS ARE FCST TO
FALL NO LOWER THAN -6C TO -8C EVEN OVER THE TIP OF THE KEWEENAW THRU
12Z SAT...TOO WARM FOR ANY LES. SO RETAINED MENTION OF SOME FREEZING
DRIZZLE AS WELL AS FINE SN/FLURRIES IN THESE UPSLOPE AREAS. AS THE
FLOW AND UPSLOPE WIND COMPONENT DIMINISHES LATE WITH ARRIVAL OF
WEAKER PRES GRADIENT...ANY -FZDZ MAY DIMINISH A BIT AS WELL. WEAKENS
DOWNSLOPE NATURE OF THE EXPECTED LLVL FLOW IN THE WAKE OF THE TROF
MAY RESULT IN SOME CLRG OVER THE SCENTRAL. OVERNGT TEMPS WL BE MUCH
WARMER THAN ON RECENT NGTS GIVEN EXPECTED CLD COVER/MODEST CHILL OF
AIRMASS. THE LOWEST MIN TEMPS ARE MOST LIKELY OVER THE SCENTRAL
WHERE MORE SUSTAINED CLRG SHUD ALLOW FOR A SHARPER TEMP DROP. SOME
FOG MAY DVLP IN THESE AREAS AS WELL WITH RELATIVELY HI SFC DEWPTS.
SAT...FOCUS SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE
PAC NW AND ARPCH OF COLD FNT FM THE N. GUIDANCE SHOWS SFC COLD FNT
AND ACCOMPANYING BAND OF H85-7 FGEN SHIFTING SLOWLY S INTO THE NRN
CWA BY EARLY AFTN AS THE FLOW TURNS MORE TO THE NNE WELL TO THE S OF
COLD HI PRES BLDG THRU CENTRAL CANADA. SINCE THE MSTR IS FCST TO
STILL BE RELATIVELY SHALLOW...FREEZING DRIZZLE AS WELL AS SOME LGT
SN/FLURRIES MAY BE THE PTYPE...ESPECIALLY IN UPSLOPE AREAS NEAR LK
SUP. BUT AS THE SHRTWV TO THE W APRCHS LATER IN THE DAY...VIGOROUS
H85-5 QVECTOR CNVGC AND SOME UPR DVGC IN RRQ OF 140KT H3 JET MAX
STREAKING ACRS ONTARIO WL BRING A RETURN OF DEEPER MSTR/HIER POPS
OVER AT LEAST THE NRN TIER. EXPECT THE HIEST TEMPS AOA FRZG OVER THE
SCENTRAL...WHERE THE FNT WL NOT LIKELY PASS UNTIL AFTER 00Z SUN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
SAT NIGHT...UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 130KT
250-300 MB JET THROUGH NRN ONTARIO/WRN QUEBEC AND ASSOCIATED 700
MB FGEN WILL RESULT IN STRONG ENOUGH UPWARD MOTION TO SUPPORT A BAND
OF SNOW FROM NRN MN THROUGH THE NRN LAKES. THE 12Z MODELS ARE IN
GENERAL AGREEMENT WITH POSITION OF HEAVIER PCPN BAND THROUGH NRN
UPPER MI. CONSENSUS QPF AMOUNTS OF 0.15-0.30 WITH SLR VALUES IN THE
15/1 RANGE WOULD GIVE SYNOPTIC SNOW AMOUNTS OF 1 TO LOCALLY 4 INCHES
...GREATEST NORTH. IN ADDITION...CYCLONIC NE TO NNE FLOW INTO NRN
UPPER MI WILL ALSO BRING ADDITIONAL LAKE ENHANCED SNOW AMOUNTS.
SINCE SLR VALUES ONLY CLIMB NEAR 20/1 LATE SAT NIGHT WITH THE
ARRIVAL OF THE COLDER AIR...ADDITIONAL ENHANCEMENT AMOUNTS IN THE 1
TO 4 INCH RANGE WOULD KEEP OVERALL TOTAL GENERALLY IN THE ADVISORY
RANGE OR BELOW 8 INCHES. BELIEVE ONLY A FEW LOCATIONS OVER THE HURON
MTNS COULD APPROACH WARNING CRITERIA OF 8 INCHES DUE TO MORE
PROLONGED FAVORABLE UPSLOPE NE FLOW. IN ADDITION...NRLY WINDS
GUSTING TO 25 TO 30 MPH IN OPEN AREAS NEAR THE LAKE SHORES WILL
PRODUCE BLOWING AND DRIFTING SNOW.
SUN...A TRANSITION FROM LAKE ENHANCED TO PURE LES IS EXPECTED AS THE
DEEPER MOISTURE AND MID-LVL Q-VECT CONV DEPARTS E WITH MOVEMENT OF
LOW PRESSURE SYSTEM. 850 MB TEMPS DROPPING INTO THE -19C TO -22C
RANGE BY 18Z AS 850-700 MB MOISTURE STILL LINGERS OVER AREA WILL
FAVOR CONTINUED MODERATE TO HEAVY LES...ESPECIALLY FOR LOCATIONS
FAVORED BY NRLY UPSLOPE FLOW. EXPECT LES RATES TO GRADUALLY DIMINISH
IN THE AFTERNOON AS WINDS BACK AND INVERSION HEIGHTS DROP TO AROUND
5K FT. WITH EXPECTED SNOWFALL AMOUNTS GENERALLY IN HIGH END OF THE
ADVISORY RANGE...WILL CONTINUE WITH A SPS TO HIGHLIGHT THE POTENTIAL
FOR SIGNIFICANT SNOWFALL. EXPECT THE GREATEST TOTAL ACCUMULATIONS
FROM IRONWOOD THROUGH THE PORCUPINE MOUNTAINS TO ROCKLAND IN THE
WEST AND FROM HERMAN THROUGH THE HURON MOUNTAINS TO NEGAUNEE OVER
THE NORTH CENTRAL. A FEW FAVORED HIGHER TERRAIN LOCATIONS COULD
APPROACH 10 TO 12 INCHES THROUGH THE EVENT.
SUN NIGHT...ENHANCED LOW-LEVEL CONVERGENCE FROM DEVELOPING LAND
BREEZES COULD FAVOR AREAS EAST OF MQT FOR ADDITIONAL MODERATE LES
ACCUMULATION. NAM BUFR SNDGS SHOW FAVORABLE PLACEMENT OF DGZ WITHIN
BEST MODEL OMEGA OF CONVECTIVE BOUNDARY LAYER SO GOOD SNOW GROWTH
AND FLUFFY LES ACCUMULATION EXPECTED. WOULD NOT BE SURPRISED TO SEE
ADVISORY SNOWFALL OF 4 INCHES OR MORE OVER PORTIONS OF ERN
ALGER...NRN SCHOOLCRAFT AND NW LUCE COUNTY WHERE MODELS SHOW BEST
LOW-LVL CONVERGENCE.
MON-WED...AS THE POLAR VORTEX GRADUALLY SHIFTS FROM HUDSON BAY TO
NRN QUEBEC...VERY COLD ARCTIC AIR WILL DOMINATE THE WRN GREAT LAKES.
WITH 850 MB TEMPS DROPPING INTO THE -25C TO -29C RANGE...LES WILL
PERSIST FOR LOCATIONS FAVORED BY NW TO W FLOW. AS TO BE EXPECTED
MODELS STILL SHOWING DIFFERENCES WITH TIMING OF SHORTWAVES MOVING
THROUGH THE REGION AND THUS ACCOMPANYING WIND SHIFTS. THERE MAY
BE PERIODS WHERE THE WINDS ARE LIGHT ENOUGH FOR LAKE INDUCED
TROUGHING TO DOMINATE THE LOW LEVEL FLOW. THE COLD AIRMASS WILL ALSO
FAVOR SMALL SNOWFLAKES THAT WILL LIMIT OVERALL ACCUMULATIONS BUT
STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS AT TIMES ASE VALUES DROP INTO THE -20 TO -35 RANGE.
THU AND FRI...MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED
PATTERN BY THE END OF THE WEEK WITH WAA DEVELOPING. SFC HIGH
PRESSURE OVER THE REGION SHOULD ENSURE MOSTLY DRY CONDITIONS ON
THURSDAY...EXCEPT FOR SOME LINGERING LIGHT WEST FLOW LES ALONG LAKE
SUPERIOR. EXPECT HIGH TEMPS THU TO REBOUND BACK INTO THE DOUBLE
DIGITS ABOVE ZERO. STRONGER WAA ON FRIDAY AHEAD OF THE NEXT
ADVANCING CLIPPER SYSTEM MAY ALLOW FOR HIGH TEMPS TO CLIMB BACK INTO
THE 20S ESPECIALLY OVER THE EAST HALF OF THE FCST AREA. BOTH THE
ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW NORTH OF LAKE SUPERIOR IN
WAA/ISENTROPIC ASCENT AND SPREAD THIS SNOW ACROSS MAINLY THE EASTERN
AND NORTH CENTRAL FCST AREA. WILL INCLUDE HIGHER CHC POPS IN FRI
FCST FOR THIS SNOW POTENTIAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1223 PM EST FRI DEC 27 2013
TRICKY AVIATION FORECAST THIS AFTERNOON WITH STRONG SSW WIND IN
ADVANCE OF DISTURBANCE DROPPING SEWD TOWARD THE UPR GRT LKS. PLENTY
OF LO CLDS JUST TO THE S OF UPR MI...BUT DOWNSLOPING HAS CAUSED
THESE CLDS TO BREAK UP AT TIMES. INCLUDED TEMPO GROUPS FOR THE FIRST
COUPLE OF HRS TO SHOW MVFR CIGS GIVEN POTENTIAL FOR SOME OF THESE
CLDS TO SURVIVE INTO THE TAF SITES...ESPECIALLY EARLY IN THE FCST
PERIOD BEFORE WARMER AIR ARRIVES. EXPECT GUSTY WINDS AT TIMES AT THE
MORE EXPOSED IWD/SAW LOCATIONS...BUT INCLUDED LLWS FOR THE MORE
SHELTERED CMX SITE. THE PASSAGE OF A LO PRES TROF TNGT FOLLOWING THE
PASSAGE OF THE DISTURBANCE SHOULD RESULT IN A WSHFT TO THE WNW AND
THE ARRIVAL OF SOME SHALLOW MSTR. MVFR CONDITIONS WL BE THE RESULT
EXCEPT AT CMX...WHERE MORE PRONOUNCED UPSLOPE COMPONENT WL BRING
ABOUT IFR CONDITIONS. THERE COULD ALSO BE SOME FLURRIES AND -FZDZ AT
IWD AND ESPECIALLY CMX. THESE LOWER CONDITIONS WL PERSIST THRU SAT
MRNG WITH THE ARRIVAL OF A COLD FNT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EST FRI DEC 27 2013
EXPECT SW WINDS UP TO 30 KTS AND SOME FREEZING SPRAY THIS EVENING TO
DIMINISH WITH ARRIVAL OF WEAKER PRES GRADIENT ACCOMPANYING A LO PRES
PASSAGE. STRONGER N WINDS AND SOME FREEZING SPRAY WILL REDEVELOP ON
SAT FOLLOWING THE PASSAGE OF ANOTHER COLD FRONT AND AS ARCTIC AIR
SURGES S IN ADVANCE OF HI PRES BUILDING INTO SCENTRAL CANADA. AS
ARCTIC AIR FLOWS S INTO THE AREA BEHIND FRONT AND NE GRADIENT
TIGHTENS BEHIND LOW PASSING TO SOUTH LOOK FOR A PERIOD OF GALES TO
DEVELOP OVER THE WEST AND NCNTRL SAT NIGHT SO HAVE ISSUED A GALE
WATCH FOR THIS POTENTIAL. OTHERWISE NE WINDS TO 30KT WILL BE COMMON
SAT NIGHT FOR THE REST OF THE LAKE BACKING TO THE NORTH ON SUNDAY.
HEAVY FREEZING SPRAY IS STILL EXPECTED OVER MUCH OF THE LAKE SAT
NIGHT INTO MONDAY. IT APPEARS THAT THE ARCTIC AIR WILL SETTLE INTO
THE UPPER LAKES FOR AN EXTENDED STAY MUCH OF NEXT WEEK...ALTHOUGH NO
GALES APPEAR EVIDENT AT THIS POINT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ265-267.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY
FOR LSZ266.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ SATURDAY
TO 1 AM EST /MIDNIGHT CST/ MONDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...VOSS/KC