Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/09/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1059 PM MDT SAT APR 6 2013
.UPDATE...
ISSUED AT 1059 PM MDT SAT APR 6 2013
CURRENT WATER VAPOR IMAGERY INDICATING SHORT WAVE EMBEDDED WITHIN
THE MODERATE WESTERLY FLOW ALOFT TRANLATING ACROSS EASTERN
COLORADO WITH DISTINCT CLEARING BEHIND SAID WAVE. REGIONAL RADARS
INDICATING ISOLATED TO SCATTERED ECHOES MOVING ACROSS THE EASTERN
PLAINS AS WELL...THOUGH WEB CAMS AND OBSERVATIONS INDICATING MAINLY
VIRGA WITH ONLY A FEW SPRINKLES MAKING IT TO THE GROUND WITH DRY
SUB CLOUD LAYER AND DEW PT DEPRESSIONS STILL 15-20F.
UPDATE ISSUED AT 558 PM MDT SAT APR 6 2013
ADDED ISOLATED POPS TO SOUTHERN PORTIONS OF THE I-25 CORRIDOR WITH
CURRENT RADAR TRENDS INDICATING ECHOES ACROSS THE AREA...THOUGH
NOT SURE HOW MUCH IF ANY IS MAKING IT TO THE GROUND WITH DEW PT
DEPRESSIONS IN EXCESS OF 20 DEGREE. WILL CONTINUE TO MONITOR RADAR
TRENDS THROUGH THE EVENING WITH EMBEDDED SHORT WAVE ACROSS WESTERN
COLORADO TRANSLATING ACROSS THE STATE AND LATEST HRRR DATA
SPREADING A FEW SHOWERS ACROSS THE PIKES PEAK AND PALMER DVD
AROUND MIDNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 323 PM MDT SAT APR 6 2013
CURRENTLY...UPPER 60S TO NR 70 FOR THE PLAINS...AND 40S-50S FOR THE
MT AREAS. WINDS GENERALLY ARE WELL BEHAVED...BUT WILL SEE A FEW
ISOLD WIND GUSTS INT EH 30KT RANGE DUE TO VIRGA. UPSTREAM SHORTWAVE
TO OUR N IS EASILY SEEN IN IR IMAGERY ACROSS NRN UT AND ID. THIS
WILL CROSS OUR AREA FROM AROUND 03Z-09Z TONIGHT...SO EXPECT THIS TO
COINCIDE WITH HIGHEST POPS OVR THE MTS. BEST CHANCE FOR SHOWERS WILL
BE OVER THE CONTDVD N OF KMYP...WHERE THE HIGHER ELEVATIONS COULD
PICK UP ONE TO THREE INCHES OF SNOW THROUGH TOMORROW FROM SCT SHSN.
TOMORROW...WILL START OFF FAIRLY QUIET...THEN COULD SEE A FEW
SHOWERS DEVELOP ACROSS THE AREA AFTER ABOUT 21Z...IN RESPONSE TO
INCREASING UPPER LIFT FROM THE APPROACHING STORM SYSTEM NOW OVER
THE N PACIFIC. INCREASING LAPSE RATES WILL LEAD TO LIFTED INDICES IN
THE MINUS TWO RANGE IN THE AFTERNOON...WHICH COULD LEAD TO A FEW LTG
STRIKES ACROSS THE AREA. BELIEVE LTG WILL BE RATHER LIMITED...BUT
WILL LEAVE MENTION IN THE FORECAST FOR NOW TO PRESERVE CONTINUITY
AND COORDINATION WITH SURROUNDING WFOS. TEMPS SHOULD BE FAIRLY CLOSE
TO TODAY`S READINGS...MAYBE A COUPLE DEGREES HIGHER AS WRLY FLOW
INCREASES.
FIRE WX DANGER ALSO IS ON THE INCREASE TOMORROW DUE TO THE INCREASE
IN WINDS AND CONTINUED DRY CONDITIONS OVERALL. BEST BET FOR CRITICAL
FIRE WX WILL BE OVER THE SAN LUIS VALLEY...WHICH SHOULD SEE GUSTS IN
THE 25-35 KT RANGE IN THE AFTERNOON AND EARLY EVE. WILL HOIST THE
RED FLAG FOR THE VALLEY FOR THIS PERIOD. ALSO COULD SEE SOME
CRITICAL FIRE WX CONDITIONS ACROSS THE LOWER ARKANSAS FROM FREMONT
INTO NRN PUEBLO COUNTY...AND IN HUERFANO COUNTY DUE TO GAP FLOW
THROUGH LA VETA PASS. AT THIS TIME...LOOKS TOO LIMITED IN SCOPE TO
INCLUDE IN THE RED FLAG...BUT MAY HAVE TO BE ADDED BY LATER SHIFTS
IF IT APPEARS THAT WINDS WILL BE MORE WIDESPREAD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 323 PM MDT SAT APR 6 2013
...POSSIBLE WEATHER TRIFECTA ACROSS SOUTHERN COLORADO MONDAY...
MONDAY HAS A LOT OF WEATHER HAZARD POTENTIAL...INCLUDING POSSIBLE
SEVERE WEATHER ON THE FAR EASTERN PLAINS...FIRE WEATHER OVER MOST
OF THE REST OF THE PLAINS AND WINTER WEATHER IN THE MOUNTAINS.
FIRST THE FIRE WEATHER. MONDAY AFTERNOON INTO EARLY EVENING DEFINITELY
LOOKS LIKE A HIGH FIRE DANGER PERIOD ACROSS MUCH OF THE SOUTHEAST
PLAINS...WITH WINDS...HUMIDITIES AND FUELS ALL MEETING CRITERIA.
WITH GUSTS TO 40 MPH...HUMIDITIES BELOW 15 PERCENT AND DRY FUELS...
THIS IS DAY WHEN OUTDOOR BURNING SHOULD BE SUSPENDED AND ANY OTHER
ACTIVITIES THAT MIGHT SPARK A FIRE SHOULD BE AVOIDED.
NOW THE SEVERE POTENTIAL. PARAMETERS ON BOTH MAJOR MODELS USED FOR THIS
TIME FRAME ARE INDICATING POSSIBLE SEVERE CONVECTION ACROSS THE FAR
EASTERN PLAINS MONDAY AFTERNOON AND EVENING. PARAMETERS INDICATE
TORNADO AS WELL AS LARGE HAIL POTENTIAL. THE THREAT AREA CURRENTLY
LOOKS EAST OF NORTH-SOUTH LINE THROUGH LA JUNTA. THUNDERSTORMS
POSSIBLE ELSEWHERE THIS DAY AS WELL BUT LIKELY NOT SEVERE.
NOW THE SNOW. IT WILL SPREAD INTO THE HIGH COUNTRY MONDAY AFTERNOON
AND START TO SPREAD ONTO THE ADJACENT PLAINS BY TUESDAY MORNING.
STILL BIG UNCERTAINTIES REGARDING THE STORM TRACK. CONTINUES TO
LOOK PRETTY CERTAIN FOR GOOD SNOW AND WIND POTENTIAL OVER THE
MOUNTAINS AND ALONG THE PALMER DIVIDE...WITH MORE IFFY POTENTIAL
ELSEWHERE. REGARDLESS OF THE MODEL...STILL LOOKS LIKE A PERIOD OF
AT LEAST SOME SNOW AND WIND FOR MOST OF SOUTHERN COLORADO...INCLUDING
THE HIGH MOUNTAIN VALLEYS AND THE SOUTHEAST PLAINS FROM LATE
MONDAY NIGHT INTO TUESDAY EVENING. AS WE GET CLOSER...WINTER
WEATHER HIGHLIGHTS WILL LIKELY BE NEEDED FOR THE MOUNTAINS AND
PALMER DIVIDE AND POSSIBLY ELSEWHERE. STORM SHOULD BE MOSTLY EAST
OF THE AREA BY WEDNESDAY EXCEPT FOR LINGERING WIND...COLD AND
MOUNTAIN SNOW SHOWERS. STAY TUNED. LW
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1059 PM MDT SAT APR 6 2013
SHORT WAVE EMBEDDED WITHIN THE MODERATE WESTERLY FLOW ALOFT
TRANLATING ACROSS EASTERN COLORADO WITH DISTINCT CLEARING BEHIND
SAID WAVE AT THIS TIME. WAVE PRODUCING MAINLY VIRGA WITH CIGS
RANGING BETWEEN 070-100 ACROSS THE PLAINS AT THIS TIME. WILL SEE
CLEARING FROM WEST TO EAST THROUGH THE REST OF THE EVENING WITH
VFR CONDITIONS CONTINUING FOR KCOS...KPUB AND KALS FOR THE NEXT
24 HOURS. COULD SEE ISOLD -TSRA DEVELOPING ACROSS THE HIGHER
TERRAIN TOMORROW AFTENROON...WHICH COULD RESULT IN SOME LOCALIZED
STRONG WIND GUSTS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING
FOR COZ228>233-235-237.
RED FLAG WARNING FROM 1 PM TO 9 PM MDT SUNDAY FOR COZ224.
&&
$$
UPDATE...MW
SHORT TERM...ROSE
LONG TERM...LW
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
940 PM EDT MON APR 8 2013
.SYNOPSIS...
A FRONT WILL STALL IN THE VICINITY OF SOUTHERN NEW ENGLAND
TONIGHT...THEN WAVER NORTH AND SOUTH MUCH OF THE WEEK. WAVES OF
LOW PRESSURE WILL MOVE ALONG THE FRONT...BRINGING PERIODS OF
UNSETTLED WEATHER. THE FRONT MAY PUSH SOUTH OF NEW ENGLAND LATE
WEDNESDAY NIGHT OR THURSDAY WITH COOLER TEMPS. ANOTHER LOW WILL
MOVE ACROSS THE REGION FRIDAY WITH A PERIOD OF HEAVY RAIN
POSSIBLE. MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THIS
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
940 PM UPDATE...
MID AND HIGH CLOUDS CONTINUE TO STREAM INTO SOUTHERN NEW ENGLAND
AND A FEW SPRINKLES ARE EVIDENT ON RADAR ACROSS WESTERN MA/CT.
THESE WILL MOVE ACROSS REGION THROUGH MIDNIGHT OR SO...BEFORE
ADDITIONAL ACTIVITY UPSTREAM ACROSS WESTERN/CENTRAL NY ARRIVES
WELL AFTER MIDNIGHT.
HIGHER RESOLUTION MODELS /NAM AND RAP/ CONTINUE TO SHOW ENOUGH
INSTABILITY OVERNIGHT FOR ELEVATED THUNDER. RAP IS A BIT SLOWER
THAN NAM...SHOWING BEST INSTABILITY CLOSER TO 12Z /AS OPPOSED TO
09Z ON NAM/. MAIN FOCUS APPEARS TO BE S OF MASS PIKE WHERE BEST
INSTABILITY IS COLLOCATED WITH TIGHT 925MB THETA-E GRADIENT AND
ENHANCEMENT FROM LOW LEVEL JET JUST OFFSHORE...BUT ALSO CAN/T
RULE OUT ISOLATED THUNDER FARTHER N. SEVERE THREAT IS MINIMAL.
MADE MINOR ADJUSTMENTS TO OVERNIGHT TEMPS BASED UPON GFS LAMP.
LOWS WILL FALL BACK INTO 40S/NEAR 50.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
TUESDAY...
LOW PRESSURE WILL BE MOVING EAST AND AWAY FROM THE NEW
HAMPSHIRE TUESDAY MORNING. ANY LEFT OVER SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS SHOULD COME TO AN END BY MID MORNING. OTHERWISE...SKIES
SHOULD BECOME PARTLY TO MOSTLY SUNNY BY LATE MORNING OR EARLY
AFTERNOON. GUSTY WESTERLY WINDS WILL ALSO DEVELOP AND ALLOW FOR
VERY GOOD MIXING TO OCCUR. HIGH TEMPS SHOULD GENERALLY BE IN THE
UPPER 60S AND LOWER 70S...WITH THE WARMER READINGS SOUTH OF THE MA
TURNPIKE. THE EXCEPTION WILL BE SOUTHERN NH...WHERE WILL KEEP
HIGHS IN THE LOWER TO MIDDLE 60S. CLOUD DEBRIS MAY HANG ON LATER
IN THAT REGION AND THEY MAY NEVER COMPLETELY WARM SECTOR.
TUESDAY NIGHT... THE FIRST PART OF THE EVENING AGAIN LOOKS DRY.
HOWEVER...ANOTHER WAVE OF LOW PRESSURE WILL BE APPROACHING FROM THE
WEST. THIS WILL RESULT IN AN AREA OF SCATTERED SHOWERS WORKING INTO
THE REGION...MAINLY DURING THE OVERNIGHT HOURS. WILL GO WITH HIGH
CHANCE TO LOW END LIKELY POPS TO COVER THIS POTENTIAL. CAN/T RULE
OUT SOME THUNDER NEAR THE SOUTH COAST...BUT CONFIDENCE WAS NOT HIGH
ENOUGH TO HAVE IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
BIG PICTURE... MIDWEEK UPPER TROUGH OVER THE ROCKIES EXTENDS FROM
BORDER TO BORDER. THIS TROUGH EJECTS INTO THE PLAINS AND GREAT
LAKES LATE WEEK AND CROSSES EASTERN CANADA/NEW ENGLAND OVER THE
WEEKEND. ANOTHER TROUGH DIGS OVER THE WESTERN USA OVER THE WEEKEND
WITH SIGNS OF A BUILDING UPPER RIDGE OVER THE EAST EARLY NEXT WEEK.
MODEL PREFERENCES... GOOD AGREEMENT AMONG MODEL CONTOUR AND THERMAL
FIELDS THROUGH THURSDAY NIGHT. AFTER THAT...THE GFS BECOMES AS MUCH
AS 24 HOURS FASTER IN MOVING THE UPPER LOW PAST NEW ENGLAND.
ENSEMBLE OUTPUT FROM THE TWO MODELS SHOWS A WIDE SPREAD OF
SOLUTIONS. WE HAVE FAVORED A MODEL BLEND TO THE EXTENT THAT THE
MODEL DATA IS AVAILABLE...WITH A LEANING TOWARD THE 00Z ECMWF.
THE DAILIES...
WEDNESDAY-THURSDAY... FRONT IS STALLED EITHER OVER SOUTHERN NEW
ENGLAND /PER THE 12Z GFS/ OR JUST TO THE SOUTH /PER THE 00Z ECMWF/.
SHORTWAVES IN THE WESTERLY FLOW ALOFT WILL GENERATE DISTURBANCES
ALONG THE FRONT. TIMING THESE DISTURBANCES IS DIFFICULT...BUT
FAVORING THE ECMWF WOULD SUGGEST A BREAK ON WEDNESDAY DURING THE DAY
FOLLOWED BY CLOUDS AND AT LEAST SCATTERED PCPN WEDNESDAY NIGHT AND
THURSDAY. SUFFICIENT SUN WEDNESDAY FOR MIXING TO 900 MB...WITH
TEMPS 9-13C MIXING TO SUPPORT MAX SFC TEMPS IN THE MID 60S TO MID
70S.
FRIDAY... LOW PRESSURE MOVES OUT OF THE PLAINS TO THE EASTERN GREAT
LAKES BY FRIDAY. LOW LEVEL JET WITH 50-60 KNOT WINDS RIDES OVER THE
STALLED FRONT DURING THE MORNING AND CREATING STRONG ISENTROPIC LIFT
ACROSS SOUTHERN NEW ENGLAND. THE GFS PAINTS A EARLY MORNING ARRIVAL
AND MIDDAY DEPARTURE SCENARIO WHILE THE 00Z ECMWF SHOWS LIFT
ARRIVING DURING THE MORNING AND LINGERING THROUGH THE AFTERNOON.
EITHER WAY...A WET DAY FOR OUR AREA WITH POTENTIAL FOR STRONG WIND
GUSTS. CURRENT FORECAST GUSTS ARE LOWER THAN THE FULL
POTENTIAL...THIS DATA WILL BE MONITORED AND ADJUSTED WITH LATER DATA
PACKAGES. TEMPS LOOK TO BE WARM ENOUGH FOR A MAINLY RAIN
EVENT...POSSIBLY SOME SNOW MIXING IN OVER NORTHERN MASS AND SOUTHERN
NH AS THE EVENT ENDS.
SATURDAY THROUGH MONDAY... THE SURFACE STORM MOVES OFF BUT THE UPPER
LOW LINGERS OVER THE MARITIMES OVER THE WEEKEND. THIS COULD KEEP
SOME CLOUDS AROUND ESPECIALLY NORTH OF THE MASS PIKE. FOR NOW WE
ARE GOING OPTIMISTIC WITH SKIES BECOMING PARTLY TO MOSTLY CLEAR.
TEMPS COME FROM HPC GRIDS. WITH THE UPPER JET NEARBY THROUGH THE
PERIOD...EXPECT TEMPS TO FLUCTUATE A LITTLE EITHER SIDE OF NORMAL.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TONIGHT...MODERATE CONFIDENCE IN A PERIOD OF MVFR CONDITIONS IN A
ROUND OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS.
TUESDAY...HIGH CONFIDENCE THAT LEFT OVER MVFR-IFR CONDITIONS EARLY
SHOULD IMPROVE TO VFR BY MID TO LATE MORNING. OTHERWISE...VFR WITH
NORTHWEST WIND GUSTS OF 25 KNOTS EXPECTED AT MANY TERMINALS.
TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. MAINLY VFR CONDITIONS
DURING THE FIRST PART OF THE NIGHT. AN AREA OF SCATTERED SHOWERS
LATE MAY RESULT IN SOME MVFR CONDITIONS DEVELOPING TOWARD DAYBREAK
WED.
KBOS TAF...MODERATE CONFIDENCE IN TAF. EAST TO SOUTHEAST SEA
BREEZES BECOME SOUTHEAST EARLY THIS EVENING. LOW PROBABILITY OF A
BRIEF THUNDERSTORM BETWEEN 7Z AND 12Z. HIGH CONFIDENCE IN NO SEA
BREEZES ON TUE WITH WNW WIND GUSTS OF 25 KNOTS DEVELOPING.
KBDL TAF...MODERATE CONFIDENCE IN TAF. LOW PROBABILITY IN A BRIEF
THUNDERSTORM BETWEEN 3Z AND 9Z.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
MODERATE CONFIDENCE ALL PERIODS.
WEDNESDAY-THURSDAY... MAINLY VFR. AREAS OF MVFR CIGS/VSBYS POSSIBLE
WEDNESDAY NIGHT AND THURSDAY IN SHOWERS.
FRIDAY...IFR/LIFR IN RAIN. EAST TO SOUTHEAST WINDS AT THE SURFACE
WITH SOUTHWEST WINDS INCREASING TO 50-60 KNOTS 2000-4000 FEET ABOVE
THE SURFACE AND PROVIDING LOW LEVEL WIND SHEAR.
SATURDAY...BECOMING VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TONIGHT...WINDS/SEAS SHOULD REMAIN BELOW SCA THRESHOLDS FOR MOST OF
THE NIGHT WITH A WEAK PRESSURE GRADIENT IN PLACE. MARGINAL SCA 5
FOOT SEAS MAY DEVELOP ACROSS THE OUTER-WATERS NEAR DAYBREAK IN
RESPONSE TO A DEVELOPING LOW LEVEL JET. A FEW THUNDERSTORMS MAY
ALSO DEVELOP NEAR DAYBREAK.
TUESDAY...SCA HOISTED FOR ALL WATERS. EXPECT NEAR SHORE NORTHWEST
25 KNOT WIND GUSTS WITH GOOD MIXING BEHIND A WAVE OF LOW PRESSURE
EXITING THE NEW HAMPSHIRE COAST. IN ADDITION...SCA SEAS EXPECTED
ACROSS OUR OUTER WATERS.
TUESDAY NIGHT...ANY LEFT OVER SCA ACROSS THE OUTER-WATERS SHOULD
DIMINISH DURING THE EVENING HOURS AS PRESSURE GRADIENT
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
MODERATE CONFIDENCE ALL PERIODS.
WEDNESDAY-THURSDAY...VARIABLE WINDS BELOW 25 KNOTS BECOMING EAST.
SEAS BELOW 5 FEET WEDNESDAY...CLIMBING TO 5-6 FEET ON THE SOUTHERN
WATERS WEDNESDAY NIGHT AND THURSDAY. SMALL CRAFT ADVISORY MAY BE
NEEDED.
FRIDAY... EAST TO SOUTHEAST WINDS REACHING 25-30 KNOTS. SEAS
BUILDING TO 5-9 FEET. SMALL CRAFT ADVISORY IS LIKELY. THERE IS A
LOW PROBABILITY OF WINDS TO GALE FORCE FOR A SHORT TIME.
SATURDAY... NORTHWEST WINDS GUSTING TO 25 KNOTS. SEAS REMAIN ABOVE
5 FEET ESPECIALLY ON THE OUTER WATERS.
&&
.FIRE WEATHER...
TUESDAY...
MINIMUM AFTERNOON RH VALUES SHOULD BE DOWN TO BETWEEN 30 AND 40
PERCENT TUESDAY AFTERNOON. NORTHWEST WIND GUSTS OF 25 TO 30 WITH
PERHAPS A FEW GUSTS NEAR 35 MPH POSSIBLE TUE AFTERNOON.
HOWEVER...GIVEN MARGINAL RH VALUES AND TONIGHT/S PRECIPITATION WILL
NOT HOIST ANY FIRE WEATHER HEADLINES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM TO 6 PM EDT TUESDAY FOR
ANZ230>234-236.
SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT TUESDAY FOR ANZ235-
237.
SMALL CRAFT ADVISORY FROM 5 AM TO 6 PM EDT TUESDAY FOR ANZ250-
251.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 PM EDT TUESDAY FOR
ANZ254>256.
&&
$$
SYNOPSIS...WTB/FRANK
NEAR TERM...JWD
SHORT TERM...FRANK
LONG TERM...WTB
AVIATION...WTB/FRANK
MARINE...WTB/FRANK
FIRE WEATHER...FRANK
AREA FORECAST DISCUSSION
NWS ALBANY NY
423 PM EDT SUN APR 7 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO TRACK NORTHEAST ACROSS THE SAINT
LAWRENCE VALLEY TONIGHT. A BAND OF SHOWERS WILL TRACK ACROSS THE
REGION INTO THIS EARLY EVENING...THEN THE WINDS AND THE SHOWERS
WILL DIMINISH. A DRY START TO THE WORK WEEK BEFORE ANOTHER LOW
PRESSURE SYSTEM APPROACHES MONDAY NIGHT WITH ANOTHER CHANCE FOR
SHOWERS. RATHER UNSETTLED CONDITIONS ARE EXPECTED FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
H2O VAPOR LOOP SHOWS A RATHER STRONG UPPER LOW TRACKING NORTHEAST
ACROSS THE ST LAWRENCE VALLEY WITH AN IMPRESSIVE SURFACE PRESSURE
GRADIENT IN PLACE ACROSS EASTERN NY. THE VWP FROM THE WSR88D SHOWS
WINDS WITHIN THE BOUNDARY LAYER ARE AROUND 40KTS. WITH FUNNELING
UP THE HUDSON VALLEY...WIND SPEEDS HAVE INCREASED WITH SEVERAL
REPORTING STATIONS GUSTING INTO THE LOW-MID 40MPH RANGE. THE
ADDITIONAL INSOLATION WE RECEIVED ALSO ASSISTED WITH MOMENTUM
TRANSFER TODAY ALONG WITH TEMPERATURES CLIMBING A COUPLE DEGREES
OF FORECAST. A BAND OF SHOWERS ALONG THE COLD FRONT HAS DEVELOPED
AND WE EVEN HAD A FEW LIGHTNING STRIKES PER THE NLDN ACROSS THE
ADIRONDACKS. WHILE THE LIGHTNING HAS DIMINISHED...THE BAND OF
SHOWERS HAS INCREASED IN COVERAGE AND FORWARD MOMENTUM THE PAST
COUPLE OF HOURS. THE LATEST HRRR REFLECTIVITY FORECASTS SUGGEST
THIS LEADING EDGE OF PRECIP WILL DIMINISH WITH ANOTHER RENEW AREA
OF SHOWERS ACROSS LAKE ONTARIO AND WESTERN NY EXPECTED TOWARD THIS
EARLY EVENING AND QUICKLY MOVE ACROSS MAINLY EASTERN NY. WE WILL
KEEP POPS INTO CHC-SCT CATEGORY THROUGH THE REMAINDER OF TODAY AND
INTO THE EVENING. COLD ADVECTION WILL COMMENCE IN THE WAKE OF
FROPA AS H850 TEMPS SETTLE BACK INTO THE LOWER SINGLE DIGITS.
WESTERLY WINDS SHOULD KEEP SOME UPSLOPE CLOUDS...ESPECIALLY ACROSS
THE WESTERN NEW ENGLAND COUNTIES. AS FOR WINDS...COULD SEE SOME
SLIGHT ENHANCEMENT THRU THE MOHAWK RIVER LATER THIS EVENING...BUT
EXPECTATIONS ARE FOR THE SURFACE RIDGE TO BUILD IN AND RELAX THE
GRADIENT AND THOSE WINDS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
MONDAY...INCREASING CONFIDENCE THAT THE RIDGE BOTH ALOFT AND THE
SURFACE WILL CREST OVER THE REGION FOR A NICE START TO THE WORK
WEEK. H850 TEMPS CLIMB A COUPLE OF DEGREES THROUGH THE DAY AND
COINCIDING WITH MIXING LAYER HEIGHTS BETWEEN H850-H900...WE SHOULD
BE ABLE TO OBTAIN AFTERNOON HIGHS L-M60S FOR VALLEY LOCATIONS AND
50S ELSEWHERE.
MONDAY NIGHT...INCREASING LOW LEVEL JET ACROSS THE LOWER AND MID
MISSISSIPPI RIVER VALLEY ALONG WITH A TIGHTENING BAROCLINIC ZONE
WILL LIKELY RESULT IN AN ORGANIZED CONVECTIVE EPISODE THAT WILL
TRACK TOWARD THE UPPER OHIO VALLEY AND LOWER GREAT LAKES REGION
MONDAY NIGHT. TRENDS FROM THE NCEP MODEL SUITE AND INTERNATIONAL
GUIDANCE ALL SUGGEST THIS SYSTEM TO TRACK ACROSS THE REGION DURING
THE EVENING AND EARLY OVERNIGHT PERIOD. AS PREVIOUS MENTIONED IN
THE EARLIER AFD/S...MID LEVEL INSTABILITY PER THE SHOWALTERS DROP
TO OR BELOW 0C TO CONTINUE TO THE MENTION OF THUNDER IN THE
FORECAST. AT THIS TIME...SEEMS THE RAINFALL AMOUNTS OF ONE QUARTER
TO ONE HALF OF AN INCH ARE TO BE EXPECTED /SEE HYDRO SECTION
BELOW/.
TUESDAY...THE STRENGTH OF THIS CONVECTIVE SYSTEM MAY JUST BE
ENOUGH TO ALLOW FOR INCREASED SUBSIDENCE FOR A RATHER NICE DAY IN
THE WAKE OF THE RAINFALL. WE WILL DECREASE POPS AND INCREASE THE
POTENTIAL FOR PARTIAL SUNSHINE. SINCE WE SHOULD BE RATHER MILD
START TO THE DAY...WE COULD SEE OUR FIRST REAL RUN AT 70F FOR THE
CAPITAL REGION WITH HIGHER CONFIDENCE OF 70S INTO THE MID HUDSON
VALLEY AND PORTIONS OF LITCHFIELD COUNTY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODEL CONSENSUS IS BETTER DURING THIS TIME FRAME COMPARED TO
EARLIER RUNS. ALL INDICATE AN UNSETTLED PATTERN DURING MUCH OF
THIS TIME FRAME AS A STRONG FRONTAL STALLS NEAR THE AREA.
THE 12Z OPERATIONAL GFS CONTINUES TO HAVE THIS FRONT STALLING THE
FURTHEST NORTH...CLOSE TO JUST NORTH OF INTERSTATE 90. THE 12Z
CANADIAN MODEL STALLED THE FRONT A LITTLE FURTHER SOUTH. THE 1Z
EUROPEAN WAS STILL THE FURTHEST SOUTH...STALLING THE FRONT CLOSER TO
THE MASON DIXON LINE.
WE HAVE LEANED WITH THE EUROPEAN SOLUTION WHICH HAPPENED TO THE
WEATHER PREDICTION CENTER (WPC) SOLUTION AS WELL.
TUESDAY NIGHT MOST MODELS FORECAST SOME SORT OF MESO-SCALE COMPLEX
(MCS) WORKING THROUGH THE AREA. THE 12Z GFS AND 12Z EUROPEAN
FORECAST MODELS INDICATE THIS WOULD TRACK FROM I-90 SOUTH...WHILE
THE CANADIAN MODEL INDICATED IT WOULD TRAVEL FURTHER NORTH. FOR
NOW...JUST WENT WITH 40 POPS OF SHOWERS EVERYWHERE ACROSS THE
REGION. OVERNIGHT LOWS WILL BE IN THE MID TO UPPER 30S NORTH...40S
MOST OTHER PLACES.
WEDNESDAY LOOKS AS IF IT MIGHT BE THE "DRIEST" OF THE PERIOD IN THAT
WE SHOULD BETWEEN AN EXISTING MCS AND PERHAPS ANOTHER LINE OF
SHOWERS APPROACHING AHEAD OF A COLD FRONT. DUE TO LACK OF CONFIDENCE
IN TIMING...WE CANNOT RULE OUT A STRAY SHOWER OR TWO...BUT MUCH OF
THE DAY COULD BE RAINFREE AND MILD WITH TEMPERATURES MAINLY IN THE
60S...EXCEPT 50S ACROSS THE ADIRONDACK PARK AND SOUTHERN GREENS. A
THUNDERSTORM CANNOT BE COMPLETELY RULED OUT (MENTIONED SLIGHT CHANCE
OF THUNDERSTORMS).
WEDNESDAY NIGHT...THE AFOREMENTIONED COLD FRONT LOOKS TO MOVE
THROUGH BRINGING AT LEAST SOME SCATTERED SHOWERS. TEMPERATURES LOOK
TO REMAIN MILD MAINLY IN THE 50S SOUTH...40S NORTH.
THEN FRONT LOOKS TO STALL...AGAIN PROBABLY SOUTH OF OUR
REGION...SOMETIME THURSDAY THROUGH FRIDAY. WAVES OF LOW PRESSURE
WILL LIKELY RIPPLE ALONG THIS FRONT...IMPOSSIBLE TO CORRECTLY TIME
THIS FAR OUT. WE MIGHT SQUEAK OUT ANOTHER MILD DAY THURSDAY WITH
HIGHS IN THE 60S FROM THE CAPITAL DISTRICT SOUTH...50S FURTHER
NORTH.
TEMPERATURES THEN COOL DOWN TO THE 40S THURSDAY NIGHT (30S NORTH).
IT WILL TURN COOLER FRIDAY WITH HIGHS ONLY 50-55 ALBANY SOUTH...40S
AND EVEN SOME UPPER 30S FURTHER TO THE NORTH.
IT DOES APPEAR A MORE SIGNIFICANT AREA OF LOW PRESSURE WILL RIDE THE
FRONT ON FRIDAY...BRINGING THE BEST CHANCE OF A SOAKING RAIN. THE
12Z EUROPEAN FORECAST MODEL STILL INSIST IT COULD BE COULD ENOUGH
FOR SOME MIXED PRECIPITATION TO FALL LATE FRIDAY INTO FRIDAY NIGHT
FROM THE CAPITAL DISTRICT NORTHWARD AS SHALLOW COLD AIR WEDGES IN
FROM THE NORTH THANKS TO A STRONG AGEOSTROPHIC NORTHERLY FLOW. H925
TEMPERATURES ON THAT MODEL DROP TO BELOW 0Z (FREEZING) WHILE H850
ARE INITIALLY WELL ABOVE 0C...BUT EVENTUALLY FALL BELOW FREEZING
LATER FRIDAY NIGHT.
FOR NOW...WE HAVE MAINLY RAIN IN THE GRIDS...BUT DO MENTION A
POSSIBLE CHANGEOVER TO SNOW MOST PLACES FRIDAY NIGHT. BEING THIS
EVENT IS STILL NEARLY A WEEK WAY...WE WILL HAVE PLENTY OF TIME TO
MONITOR THE LATEST TRENDS.
THE WHOLE DISTURBANCE SHOULD LIFT OUT TO OUR NORTHEAST SATURDAY. IN
ITS WAKE...A CHILLY BREEZY DAY AWAITS US SATURDAY...WITH SOME
MODERATION BY SUNDAY.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS AND GUSTY WINDS WILL PREVAIL THROUGH THE REMAINDER OF
THE AFTERNOON. A WARM FRONT WILL APPROACH THE AREA FROM THE
SOUTH...LOWERING CEILINGS CLOSE TO MVFR LEVELS...BEFORE HIGH
PRESSURE BUILDS ACROSS THE REGION FOR MONDAY.
THIS AFTERNOON...GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON AS TERRAIN CHANNELING AND DEEP BOUNDARY
LAYER MIXING CONTINUE WITH NOW INCREASED DAYTIME HEATING DUE TO
CLEARING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM PER THE LATEST
VISIBLE SATELLITE IMAGERY. CLOUD COVER WILL GRADUALLY FILL IN LATE
IN THE AFTERNOON WITH SCATTERED SHOWERS DEVELOPING AS WELL. HOWEVER
CONFIDENCE REMAINS LOW REGARDING THE AREAL COVERAGE OF THESE
SHOWERS...SO HAVE MENTIONED JUST VCSH IN THE TAFS.
TONIGHT INTO MONDAY...AS A LOW PRESSURE SYSTEM AND ITS ASSOCIATED
BOUNDARIES MOVE ACROSS THE REGION TONIGHT...CLOUD COVER WILL
CONTINUE TO INCREASE WITH LOWERED CEILINGS. MVFR CEILINGS WILL BE
POSSIBLE AT KPSF TOWARDS DAYBREAK...BUT SHOULD REMAIN AT VFR LEVELS
AT KGFL/KALB/KPOU. HIGH PRESSURE WILL BUILD IN ACROSS THE REGION FOR
MONDAY...ALLOWING SKIES TO CLEAR BY MONDAY AFTERNOON.
WINDS WILL DIMINISH THROUGH THE OVERNIGHT AND SHIFT WESTERLY TO
GENERALLY 5-10 KNOTS.
OUTLOOK...
MON NIGHT-THU....VFR/MVFR CHC SHOWERS.
&&
.FIRE WEATHER...
THE COLD FRONT WILL MOVE THROUGH TONIGHT WITH THE SHOWERS
ENDING...AND THE RH VALUES INCREASING TO 75 TO 95 PERCENT WITH THE
WINDS SHIFTING TO THE WEST NORTHWEST AT 5 TO 15 MPH...WITH A FEW
HIGHER GUSTS INTO THE MOHAWK VALLEY...CAPITAL REGION AND
BERKSHIRES THIS EVENING.
HIGH PRESSURE WILL BRING DRY WEATHER ON MONDAY WITH MUCH LIGHTER
WINDS. THE RH VALUES WILL DROP TO 30 TO 45 PERCENT BY THE MID TO
LATE AFTERNOON.
&&
.HYDROLOGY...
NO WIDESPREAD HYDROLOGY PROBLEMS ARE EXPECTED AT THIS TIME...HOWEVER
THERE IS MUCH UNCERTAINTY IN THE FORECAST AS WE HEAD THROUGH THE
WEEK WITH REGARDS TO PRECIPITATION AND THE AMOUNTS OF SNOWMELT THAT
WILL OCCUR. THE WEATHER WILL BE UNSETTLED MUCH OF THE WEEK.
A CONVECTIVE COMPLEX IS EXPECTED TO IMPACT THE REGION MONDAY
NIGHT. AT THIS TIME...RAINFALL AMOUNTS OF ONE QUARTER TO ONE HALF
AN INCH ARE EXPECTED. COMBINE THAT WITH MILD TEMPERATURES SHOULD
RESULT WITH AN INCREASE WATER FLOWS INTO AREA RIVERS AND STREAMS.
AT THIS TIME...EXPECTATIONS ARE FOR WITHIN BANK WATER RISES.
TEMPERATURES ARE EXPECTED TO WARM TO ABOVE NORMAL ESPECIALLY ON
TUESDAY WITH A RETURN TO MORE SEASONABLE READINGS LATER IN THE
WEEK. THE DEPARTURES FROM NORMAL ARE NOT EXPECTED TO BE AS
PRONOUNCED ACROSS THE HIGHER TERRAIN WHERE THE SNOWPACK IS...PLUS
TEMPERATURES AT NIGHT ARE EXPECTED TO COOL DOWN ENOUGH TO SLOW THE
SNOWMELT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ038>041-
043-048>050-052>054-059>061-064>066-083-084.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ041>043-049-
050-052-053-059-060-083-084.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...HWJIV
AVIATION...IRL
FIRE WEATHER...BGM
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
305 PM EDT SUN APR 7 2013
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UNAMPLIFIED UPPER LEVEL
PATTERN IN PLACE OVER THE CONUS OUTSIDE OF A FEW MINOR SHORTWAVE
"KINKS" IN THE FLOW. ZONAL FLOW IS IN PLACE OVER THE NORTHERN GULF
COAST AND FLORIDA PENINSULA AND WILL HOLD FOR AT LEAST THE NEXT 24
HOURS. ONE VERY MINOR IMPULSE WITHIN THE ZONAL FLOW IS LOCATED OVER
THE EASTERN GULF AND WILL PASS OVER THIS EVENING/TONIGHT WITH LITTLE
TO NO INFLUENCE ON OUR WEATHER.
AT THE SURFACE...HIGH PRESSURE EXTENDS DOWN THE EASTERN SEABOARD AND
CONTINUES TO RIDGE ALL THE WAY TO THE FL PENINSULA AND
CENTRAL/EASTERN GULF. GRADIENT AROUND THIS RIDGE IS PROVIDING A
GENERAL EASTERLY WIND PATTERN. SIMILAR TO SATURDAY...STILL HAVE A
RATHER MOIST LAYER SEEN ON TIME HEIGHT/CROSS SECTION ANALYSIS
BETWEEN AROUND 950-825MB. THE 12Z KTBW SOUNDING PROFILE CONFIRMS
THIS NWP FORECAST. WITH THE MOISTURE IN PLACE...DIURNAL HEATING
CONTINUES TO MIX UP INTO THE COLUMN RESULTING IN A SHALLOW SCT-BKN
CU FIELD EXPANDING ACROSS THE PENINSULA FROM EAST TO WEST. THIS CU
FIELD WILL DISSIPATE THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
&&
.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
TONIGHT...
QUIET AND SEASONABLE OVERNIGHT PERIOD ON TAP. MOSTLY CLEAR SKIES
EXPECTED WITH TEMPERATURES DROPPING TO THE MIDDLE AND UPPER 50S FOR
MANY INLAND LOCATIONS BY SUNRISE...AND HOLDING IN THE 60S AT THE
COAST FROM PINELLAS COUNTY SOUTHWARD ALONG THE SUN COAST.
MONDAY/MONDAY NIGHT...
ZONAL FLOW PATTERN ALOFT WILL SLOWLY BEGIN TO TRANSITION TOWARD
RIDGING THROUGH THE DAY...AND COMPLETE THE TRANSITION MONDAY NIGHT.
AT THE SURFACE...AN EAST TO SOUTHEAST FLOW PATTERN WILL HOLD IN
PLACE ON THE SOUTHERN SIDE OF A RIDGE AXIS OFF THE GA/SC COAST.
EFFICIENT DIURNAL MIXING AND 800-850MB TEMPS AROUND 12C SHOULD
EASILY ALLOW AFTERNOON TEMPS TO MIX OUT TO THE LOWER AND MIDDLE 80S
AWAY FROM THE BEACHES. SIMILAR TO TODAY...THE STRONG TERRESTRIAL
HEATING AND WEAKER AFTERNOON GRADIENT WILL ALLOW AN ONSHORE WIND
COMPONENT TO DEVELOP AT THE COAST AND HOLD TEMPS DOWN IN THE 70S
OFF THE SHELF WATERS. MOSTLY SUNNY SKIES TO START THE DAY WILL FILL
IN WITH A SCT-BKN CU FIELD FOR A GENERALLY PARTLY CLOUDY AFTERNOON
FORECAST. A SLOW INFLUX IN LOW LEVEL MOISTURE WILL CONTINUE THE RISE
IN OVERNIGHT LOWS. MANY SPOTS BY MONDAY NIGHT OUTSIDE OF THE NATURE
COAST WILL STRUGGLE TO FALL BELOW 60 BY SUNRISE. NORMALLY COLDER
NATURE COAST LOCATIONS SHOULD FALL NO LOWER THAN THE MID 50S.
TUESDAY/TUESDAY NIGHT...
A WARM APRIL DAY SEEMS ON TAP UNDER A MIX OF SUN AND CLOUDS. LOW
LEVEL COLUMN CONTINUES TO MODIFY UNDER STACKED RIDGING. AFTERNOON
HIGH TEMPERATURES AWAY FROM THE BEACHES SHOULD RISE WELL INTO THE
80S FOR MOST LOCATIONS...AND WOULD NOT BE SURPRISED TO SEE A FEW 90
DEGREE READINGS BY LATE IN THE DAY. A SLIGHTLY BETTER MOISTURE
PROFILE OVER THE SOUTHERN THIRD OF THE FORECAST AREA MAY BE JUST
ENOUGH TO SUPPORT AN ISOLATED AFTERNOON SHOWER OR 2 ALONG THE
SEA-BREEZE. HOWEVER...USUALLY THIS TIME OF YEAR...YOU NEED SOME
SYNOPTIC HELP TO GET ANY SEA-BREEZE INDUCED CONVECTION TO FIRE. THE
UPPER RIDGE OVERHEAD WILL CERTAINLY NOT PROVIDE THIS SUPPORT...AND
FOR NOW WILL KEEP POPS AT SILENT 10% DOWN TOWARD CHARLOTTE AND LEE
COUNTIES. TUESDAY NIGHT LOOKS WARM WITH OVERNIGHT LOW TEMPS HOLDING
AROUND 60S FAR NORTH AND IN THE LOWER/MIDDLE 60S SOUTH. ENJOY!
&&
.LONG TERM (WEDNESDAY-SUNDAY)...
MEDIUM RANGE GUIDANCE IS IN SLIGHTLY BETTER AGREEMENT COMPARED TO
PREVIOUS MODEL CYCLES...HOWEVER SOLUTIONS CONTINUE TO DIVERGE LATE
NEXT WEEK AND INTO THE UPCOMING WEEKEND WITH RESPECT TO THE
PROGRESSIVENESS OF A COLD FRONT THROUGH THE AREA. WILL CONTINUE TO
TAKE A BLENDED FORECAST APPROACH FOR NOW UNTIL THE MODEL SOLUTIONS
COME INTO BETTER AGREEMENT. AS A RESULT...WILL NEED TO KEEP SLIGHT
CHANCE OR LOW CHANCE POPS IN THE FORECAST EACH DAY THROUGH THE LONG
TERM PERIOD...FOR PRIMARILY AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS. TEMPERATURES ARE EXPECTED TO RUN ABOVE NORMAL THROUGH
FRIDAY BEFORE SETTLING BACK CLOSER TO SEASONAL LEVELS OVER THE
UPCOMING WEEKEND.
&&
.AVIATION...
VFR CONDITIONS WITH FEW-SCT CU/SC AND SOME CIRRUS. GENERALLY
EASTERLY WINDS WITH A LATE SEA BREEZE CLOSE TO THE COAST.
&&
.MARINE...
THE EASTERN GULF OF MEXICO WILL REMAIN ON THE SOUTHERN SIDE OF A
RIDGE AXIS EXTENDING OFF THE GA/SC COAST THROUGH THE NEXT SEVERAL
DAYS. RESULTING GRADIENT WILL PROVIDE A GENERAL EASTERLY FLOW TO THE
REGION...HOWEVER MARINERS SHOULD ANTICIPATE WINDS BECOMING LOCALLY
ONSHORE THE NEXT COUPLE OF AFTERNOON NEAR THE COAST WITH THE
DEVELOPMENT OF THE SEA-BREEZE. THE NEXT FRONT WILL NOT APPROACH THE
REGION UNTIL THE LATTER PORTION OF THE WEEK WITH SOUTHEAST AND SOUTH
WINDS INCREASING AHEAD OF THIS SYSTEM.
&&
.FIRE WEATHER...
RISING TEMPERATURES THE NEXT SEVERAL DAYS WILL ALSO BE ACCOMPANIED
BY A SLOW INCREASE IN LOW LEVEL MOISTURE. RELATIVE HUMIDITY VALUES
WILL BOTTOM OUT IN THE UPPER 30S TO AROUND 40 PERCENT THE NEXT
SEVERAL DAYS DURING THE AFTERNOON...AND NO RED FLAG CONDITIONS ARE
ANTICIPATED. PATCHY FOG WILL BE INTRODUCED TO THE FORECAST FOR LATE
MONDAY NIGHT AND EARLY TUESDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 63 82 65 85 / 0 0 0 10
FMY 63 86 65 85 / 0 0 0 10
GIF 59 86 61 87 / 0 0 0 10
SRQ 62 79 62 83 / 0 0 0 10
BKV 54 85 57 86 / 0 0 0 0
SPG 64 82 66 82 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS MIAMI FL
219 PM EDT SUN APR 7 2013
.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
PLACED AN ISOLATED POP GRID FOR ALL ZONES THE REMAINDER OF THIS
AFTERNOON. THE ONSHORE FLOW OF A FEW SHOWERS ALONG THE EAST COAST
HAS BEEN PERSISTENT AND THE HRRR DOES INDICATE A CONTINUATION OF
ISOLATED ACTIVITY DEVELOPING ACROSS THE INTERIOR AND COASTAL
COLLIER COUNTY UNTIL VERY EARLY THIS EVENING.
GLOBAL MODELS IN VERY GOOD AGREEMENT OVER THE NEXT 48-60 HOURS
WITH MID LEVEL ZONAL FLOW THROUGH EARLY TUESDAY AND SURFACE HIGH
PRESSURE ACROSS THE ATLANTIC AND NORTH FLORIDA. THIS WILL MAINTAIN
A MODEST EASTERLY LOW LEVEL WIND FLOW AND A MOSTLY DRY WEATHER
REGIME WITH STRONG SUBSIDENCE CAP REMAINING INTACT. THERE IS A
SMALL INCREASE IN PWAT VALUES THAT WILL BE ROTATING WESTWARD
BENEATH THE LARGE SCALE LOW LEVEL RIDGE OVER THE ATLANTIC THAT THE
MODELS SHOW ARRIVING ACROSS SOUTH FLORIDA BY LATE TUESDAY AND
TUESDAY NIGHT. FORECAST SOUNDINGS ALSO INDICATE THE CAP WILL BEGIN
TO ERODE BY THIS TIME AND THIS SHOULD ALLOW FOR A SLIGHT INCREASE
IN SHOWER ACTIVITY MOVING FROM THE ATLANTIC ONTO THE SOUTHEAST
COAST. FOR THIS REASON, WILL MAINTAIN A SLIGHT CHANCE POP ALONG
THE EAST COAST TUESDAY NIGHT AND SILENT POP ELSEWHERE AS RAIN
CHANCES OVER THE INTERIOR AND COASTAL COLLIER COUNTY WILL BE TOO
SMALL TO MENTION IN THOSE LOCATIONS. IN ADDITION, THE SHORT RANGE
ENSEMBLE (SREF) IS SHOWING A SUBSTANTIAL INCREASED CHANCE FOR FOG
OVER THE INTERIOR AND SOUTHWEST COAST FOR MONDAY NIGHT AND TUESDAY
NIGHT AS THE LOW LEVEL MOISTURE INCREASES SO WILL INTRODUCE PATCHY
FOG FOR THOSE LOCATIONS AT THAT TIME.
.LONG TERM (WEDNESDAY THROUGH SUNDAY)...
LOOKING AHEAD TOWARDS THE MIDDLE AND END OF THE WEEK, THE FORECAST
BECOMES INCREASINGLY UNCERTAIN AS THE GFS AND ECMWF CONTINUE TO
DIVERGE ON THE EVOLUTION OF THE POWERFUL MID LEVEL TROUGH THAT WILL
BE MOVING INTO THE CENTRAL PLAINS STATES MONDAY NIGHT AND TUESDAY
THEN SHIFTING EAST THROUGH THE WEEK. THE GFS PHASES IT IN WITH A
NORTHERN STREAM TROUGH BY LATE WEDNESDAY AND THURSDAY AS THE MAIN
SYSTEM LIFTS EAST INTO THE ATLANTIC. THIS BRINGS A TRAILING COLD
FRONT ACROSS SOUTH FLORIDA ON FRIDAY SLOWLY PUSHING THROUGH THE
REGION AND OFF THE SOUTHEAST COAST LATE SATURDAY AND SUNDAY. THIS
WOULD ALSO BRING AN INCREASED CHANCE FOR CONVECTION ON FRIDAY AND
POSSIBLY LINGERING INTO SATURDAY AS SHOWN BY THE LATEST MEX
GUIDANCE. HOWEVER, THE ECMWF IS ALSO HOLDING ONTO ITS SLOWER
SOLUTION WITH THE CENTRAL PLAINS TROUGH PHASING WITH THE UPSTREAM
SYSTEM BUT FARTHER TO THE NORTH. IT THEN SHOWS THE FRONT STALLING
ACROSS CENTRAL FLORIDA SATURDAY AND SUNDAY SO THE HIGHEST POPS WOULD
BE OVER NEXT WEEKEND. AT THIS TIME, IT IS A WAIT AND SEE APPROACH
WITH LITTLE CHANGE TO THE CURRENT FORECAST.
&&
.MARINE...
WIND AND SEAS WILL REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF
THIS WEEK WITH A LIGHT TO MODERATE EAST TO SOUTHEAST WIND AND SEAS
OF 5 FEET OR LESS. THE WIND WILL INCREASE AND BECOME MORE
SOUTHERLY BY FRIDAY AS A COLD FRONT MOVES INTO NORTH FLORIDA AND
THE HIGH PRESSURE SHIFTS FARTHER EAST INTO THE ATLANTIC.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS
THROUGH THE END OF THIS WEEK AS LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE. THIS WILL ALSO INCREASE THE LIKELIHOOD FOR SOME LATE
NIGHT FOG FORMATION OVER THE INTERIOR AND SOUTHWEST COAST AS THE
WEEK PROGRESSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 67 80 69 81 / - - 10 10
FORT LAUDERDALE 70 80 70 82 / - - 10 10
MIAMI 68 77 71 82 / - - 10 10
NAPLES 65 81 65 84 / - - - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1120 AM EDT SUN APR 7 2013
.UPDATE (REST OF TODAY AND TONIGHT)...
BENIGN WEATHER WILL CONTINUE THROUGH TONIGHT WITH DRY CONDITIONS AND
SEASONABLE TEMPERATURES.
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UNAMPLIFIED UPPER LEVEL
PATTERN IN PLACE OVER THE CONUS OUTSIDE OF A FEW MINOR SHORTWAVE
"KINKS" IN THE FLOW. ZONAL FLOW IS IN PLACE OVER THE NORTHERN GULF
COAST AND FLORIDA PENINSULA AND WILL HOLD FOR AT LEAST THE NEXT 24
HOURS. ONE VERY MINOR IMPULSE WITHIN THE ZONAL FLOW IS LOCATED OVER
THE CENTRAL/EASTERN GULF AND WILL PASS OVER THIS EVENING/TONIGHT. WE
HAVE SEEN A FEW HIGH LEVEL CIRRUS OUT AHEAD OF THIS FEATURE...
HOWEVER AS IT APPROACHES...THE SYNOPTIC SUPPORT FOR THIS CIRRUS IS
ALREADY BEGINNING TO PASS BY.
AT THE SURFACE...HIGH PRESSURE EXTENDS DOWN THE EASTERN SEABOARD AND
CONTINUES TO RIDGE ALL THE WAY TO THE FL PENINSULA AND
CENTRAL/EASTERN GULF. GRADIENT AROUND THIS RIDGE IS PROVIDING A
GENERAL EASTERLY WIND PATTERN. SIMILAR TO SATURDAY...STILL HAVE A
RATHER MOIST LAYER SEEN ON TIME HEIGHT/CROSS SECTION ANALYSIS
BETWEEN AROUND 950-985MB. THE 12Z KTBW SOUNDING PROFILE CONFIRMS
THIS NWP FORECAST. WITH THE MOISTURE IN PLACE...AS DIURNAL HEATING
CONTINUES TO MIX UP INTO THE COLUMN WE SHOULD AGAIN SEE A SHALLOW
SCT-BKN CU FIELD EXPANDING ACROSS THE PENINSULA FROM EAST TO WEST
DURING THE NEXT SEVERAL HOURS.
MIXED ON SATURDAY TO AROUND 800MB PER 00Z KTBW SOUNDING. EXPECT
SIMILAR MIXING TODAY...WHICH WITH 800-850MB TEMPS AROUND 9-10C WILL
MIX DOWN TO HIGH TEMPERATURES IN THE LOWER 80S FOR MANY
LOCATIONS...EVEN SOME MIDDLE 80S FOR THE FAR SOUTHERN ZONES WHERE
LOW LEVEL COLUMN IS EVEN WARMER. THE STRONG TERRESTRIAL HEATING
SHOULD FORCE AN ONSHORE COMPONENT SEA-BREEZE TO DEVELOP DURING THE
EARLY AFTERNOON...AND THIS WILL KEEP THE BEACHES SEVERAL DEGREES
COOLER WITH THE FLOW OFF THE SHELF WATERS.
QUIET AND SEASONABLE OVERNIGHT PERIOD ON TAP. MOSTLY CLEAR SKIES
EXPECTED WITH TEMPERATURES DROPPING TO THE MIDDLE AND UPPER 50S FOR
MANY INLAND LOCATIONS BY SUNRISE...AND HOLDING IN THE 60S AT THE
COAST FROM PINELLAS COUNTY SOUTHWARD ALONG THE SUN COAST. ENJOY!
&&
.AVIATION...
VFR CONDITIONS UNDER SCT CU/SC AND OCNL BKN CIRRUS. EAST AND SE WINDS
SHIFT TO WESTERLY AT COASTAL TERMINALS IN THE AFTERNOON...AT 10KT OR
LESS.
&&
.MARINE...
THE EASTERN GULF OF MEXICO WILL REMAIN ON THE SOUTHERN SIDE OF A
RIDGE AXIS EXTENDING OFF THE GA/SC COAST THROUGH THE NEXT SEVERAL
DAYS. RESULTING GRADIENT WILL PROVIDE A GENERAL EASTERLY FLOW TO THE
REGION...HOWEVER MARINERS SHOULD ANTICIPATE WINDS BECOMING LOCALLY
ONSHORE THE NEXT COUPLE OF AFTERNOON NEAR THE COAST WITH THE
DEVELOPMENT OF THE SEA-BREEZE. THE NEXT FRONT WILL NOT APPROACH THE
REGION UNTIL THE LATTER PORTION OF THE WEEK WITH SOUTHEAST AND SOUTH
WINDS INCREASING AHEAD OF THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 63 83 65 / 0 10 0 0
FMY 82 63 85 63 / 10 0 0 0
GIF 82 61 85 62 / 10 0 10 10
SRQ 79 61 82 63 / 10 0 0 0
BKV 82 55 84 57 / 10 10 10 10
SPG 79 66 83 68 / 10 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
633 AM EDT SUN APR 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH MID WEEK. A COLD FRONT WILL
APPROACH THE AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THROUGH SUNRISE...SATELLITE...SOUTH CAROLINA DOT WEBCAMS AND
SURFACE OBSERVATIONS SHOW LOW CLOUDS AND DENSE FOG ARE EXPANDING
RAPIDLY SOUTH OUT OF BERKELEY COUNTY. THE BERKELEY COUNTY WARNING
POINT AS WELL AS AWOS OBSERVATIONS FROM KMKS AND KDYB INDICATE
VSBYS ARE RUNNING ABOUT 1/4-1/2 MILE. A DENSE FOG ADVISORY HAS
BEEN ISSUED FOR DORCHESTER AND BERKELEY COUNTIES UNTIL 9 AM...BUT
MAY NEED TO BE EXPANDED TO INCLUDE CHARLESTON AND COLLETON
COUNTIES PRIOR TO SUNRISE. UPDATED GRIDDED AND TEXT FORECASTS TO
REFLECT GOING TRENDS.
TODAY...LARGE SOUTHWEST-NORTHEAST ORIENTED HIGH PRESSURE CENTERED
OFF NEW ENGLAND WILL STEADILY SHIFT FARTHER OFFSHORE TODAY AS A
FAIRLY ZONAL FLOW DOMINATES ALOFT. ONGOING WEAK WARM ADVECTION
WILL PUSH H8 TEMPERATURES INTO THE 8-9C RANGE WHICH WILL YIELD
SLIGHTLY WARMER HIGH TEMPERATURES COMPARED TO SATURDAY. LOW-LEVEL
THICKNESSES SCHEMES AND MODEL BUFR SOUNDINGS GENERALLY SUPPORT
HIGHS IN THE LOWER-MID 70S WITH CONSIDERABLY COOLER TEMPERATURES
IN THE LOWER 60S AT THE BEACHES WHERE OCEANIC INFLUENCES WILL BE
THE GREATEST. EXPECT ANOTHER RATHER ROBUST SEA BREEZE CIRCULATION
TO FORM ALONG THE BEACHES LATER TODAY WHICH WILL MOVE STEADILY
INLAND DURING THE AFTERNOON HOURS. THIS WILL CAUSE TEMPERATURES TO
DROP ABOUT 5-8 DEGREES ACROSS THE COASTAL COUNTIES WITH ITS
PASSAGE...SIMILAR TO SATURDAY. WITH THE LACK OF STRATOCUMULUS
THIS MORNING...ITS UNCLEAR EXACTLY HOW MUCH CUMULUS WILL DEVELOP
LATER TODAY AS TEMPERATURES WARM INTO THE 70S. SUSPECT THERE WILL
BE AT LEAST A SHALLOW...SOMEWHAT SCATTERED CUMULUS FIELD AHEAD OF
THE SEA BREEZE SO WILL STICK WITH A PARTLY CLOUDY SKIES CHARACTER
FOR TODAY. SKIES WILL LIKELY CLEAR A BIT IN THE WAKE OF THE SEA
BREEZE AS MORE STABLE AIR IS DRAWN INLAND FROM OFF THE ATLANTIC.
THIS MAY RESULT IN A PERIOD OF MOSTLY SUNNY TO SUNNY SKIES PRIOR
TO SUNSET...MAINLY ACROSS THE COASTAL CORRIDORS. NO RAIN IS
EXPECTED EVEN AS THE COASTAL FRONT DRAWS CLOSER TO THE COAST AND
EVENTUALLY BECOMES ABSORBED IN THE BROADER SYNOPTIC FLOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...THE AREA WILL REMAIN ALONG THE WESTERN FRINGES OF
ATLANTIC HIGH PRESSURE TONIGHT. EXPECT MAINLY CLEAR SKIES TO
DOMINATE WITH SOME PATCHY STRATOCUMULUS POSSIBLY MOVING INLAND
FROM OFF THE ATLANTIC. THE BOUNDARY LAYER SHOULD DECOUPLE FOR MOST
AREA AWAY FROM THE IMMEDIATE COAST A FEW HOURS AFTER SUNSET.
GENERALLY FAVORED THE COOLER SIDE OF GUIDANCE GIVEN THE DECENT
RADIATIONAL SETUP. LOWS WILL RANGE FROM THE LOWER 50S INLAND TO
THE MID 50S ALONG THE IMMEDIATE COAST. A FEW UPPER 40S CAN NOT BE
COMPLETELY RULED OUT...MAINLY IN THE NORMALLY COLDER LOCATIONS
SUCH AS ALLENDALE AND JAMESTOWN. COULD SEE SOME SHALLOW GROUND FOG
FORM AFTER MIDNIGHT...BUT ITS PROBABLY NOT WORTH MENTIONING GIVEN
THE LACK OF ANY SIGNIFICANT IMPACT.
MONDAY AND TUESDAY...THE FORECAST AREA WILL REMAIN ON THE PERIPHERY
OF SURFACE HIGH PRESSURE IN THE ATLANTIC EARLY NEXT WEEK. THE UPPER
LEVEL PATTERN WILL BECOME MORE AMPLIFIED BY TUESDAY...AS A DEEP
TROUGH SHIFTS INTO THE CENTRAL PLAINS AND RIDGING STRENGTHENS ACROSS
THE SOUTHEAST COAST. RISING HEIGHTS ALOFT AND SOUTH/SOUTHEAST FLOW
WILL SUPPORT UNSEASONABLY WARM CONDITIONS EACH AFTERNOON. HIGH
TEMPERATURES INLAND WILL RISE INTO THE UPPER 70S TO LOWER 80S ON
MONDAY...WHILE WARMING SOLIDLY INTO THE LOWER 80S BY TUESDAY. THE
ONSHORE COMPONENT TO THE SURFACE FLOW WILL KEEP COASTAL LOCATIONS
NOTABLY COOLER...SUPPRESSING HIGH TEMPERATURES IN THE LOWER TO MID
70S NEAR THE BEACHES. ALTHOUGH LOW LEVEL MOISTURE WILL BE
INCREASING...AND A SEABREEZE BOUNDARY WILL DEVELOP WITHIN MORE
SUMMER-LIKE CONDITIONS...DECENT SUBSIDENCE SHOULD PREVENT DIURNAL
SHOWER DEVELOPMENT. HAVE THUS CAPPED RAIN CHANCES BELOW 15 PERCENT.
WEDNESDAY...DEEP LAYER RIDGING WILL GRADUALLY SHIFT FARTHER INTO
THE ATLANTIC BY MID WEEK...WHILE THE ROBUST UPPER TROUGH
STRETCHING FROM THE NORTHERN PLAINS TO THE SOUTHWEST STATES MAKES
SOME PROGRESS EASTWARD. THIS SYSTEM WILL PROVIDE THE ENERGY TO
SPAWN A SURFACE LOW AND TRAILING COLD FRONT TO THE WEST OF THE
FORECAST AREA. THE GFS MODEL SOLUTIONS HAVE BEEN CONSISTENTLY MORE
AGGRESSIVE IN BREAKING DOWN THE DEEP RIDGING...DECREASING
SUBSIDENCE ENOUGH TO SUPPORT DIURNAL SHOWER DEVELOPMENT WEDNESDAY
AFTERNOON. PREFER TO LEAN TOWARD A MORE CONSERVATIVE AND SLOWER
SCENARIO...THUS CONTINUING TO KEEP RAIN CHANCES BELOW 15 PERCENT.
WILL ALSO CONTINUE TO INDICATE UNSEASONABLY WARM HIGH
TEMPERATURES...REACHING THE LOWER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE DURING THE AFTERNOON HOURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE MODEL SOLUTIONS MAINTAIN SIGNIFICANT DISCREPANCIES IN
THE TIMING OF A COLD FRONT APPROACHING FROM THE WEST LATE IN THE
WEEK. AN ELONGATED UPPER TROUGH OVER THE CENTRAL PLAINS WEDNESDAY
NIGHT WILL BREAK INTO A MORE SPLIT FLOW FEATURE BY THURSDAY.
SLOWER MODEL SOLUTIONS SUGGEST THE SOUTHERN SHORTWAVE ENERGY WILL
SPIN UP A SECONDARY SURFACE LOW ALONG THE GULF COAST STATES THAT
COULD DELAY THE PROGRESS OF THE FRONTAL SYSTEM. IN ADDITION...THERE
IS SOME QUESTION AS TO THE RESILIENCY OF THE UPPER RIDGE AND
SUBSEQUENT IMPACTS ON PRECIPITATION TIMING AND COVERAGE. UPON
COLLABORATION WITH NEIGHBORING FORECAST OFFICES...PREFER TO LEAN
TOWARD THE SLOWER MODELS SOLUTIONS AT THIS TIME. WILL INTRODUCE A
SLIGHT CHANCE OF RAIN FROM WEST TO EAST AS EARLY AS THURSDAY...YET
SUGGEST THE HIGHEST POTENTIAL FOR SHOWER/THUNDERSTORM COVERAGE
FRIDAY AFTERNOON AND EVENING...WHEN THE SOUTHERN STREAM SHORTWAVE
AND SURFACE LOW LIFT INTO THE AREA. REGARDLESS OF MODEL
SOLUTION...THE UNSEASONABLY WARM CONDITIONS AHEAD OF THE FRONTAL
SYSTEM WILL SUPPORT DECENT INSTABILITY AND SUBSEQUENT THUNDERSTORM
DEVELOPMENT. THIS INSTABILITY...WHEN COMBINED WITH A POTENTIAL 40
TO 50 KT LOW LEVEL JET...COULD ALSO ALLOW THUNDERSTORMS TO BECOME
STRONG AND ORGANIZED. HOWEVER...CONFIDENCE IN SUCH DETAILS THIS
FAR OUT REMAINS LOW...ESPECIALLY CONSIDERING CURRENT MODEL
CONSISTENCY ISSUES.
EXPECT THE COLD FRONT TO HAVE CROSSED THE EAST COAST BY FRIDAY
NIGHT...WITH SURFACE HIGH PRESSURE RAPIDLY REBUILDING FROM THE WEST
IN ITS WAKE. HAVE MAINTAINED JUST A SLIGHT CHANCE FOR
SHOWERS/THUNDERSTORMS INTO EARLY SATURDAY...WITH POPS FALLING
BELOW 15 PERCENT FOR THE REMAINDER OF THE WEEKEND. HIGH
TEMPERATURES WILL BE A FEW DEGREES COOLER FROM FRIDAY AFTERNOON
THROUGH SUNDAY...BECOMING CLOSER TO SEASONAL NORMALS IN THE MID
70S BY THE WEEKEND.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
GENERALLY VFR. INCREASING MOISTURE FROM OFF THE ATLANTIC WILL
LIKELY SUPPORT SOME STRATOCUMULUS THROUGH SUNRISE. ITS STILL
UNCLEAR AT THIS POINT HOW WIDESPREAD THESE CLOUDS WILL BECOME BUT
LATEST RAP DATA SUGGESTS ANY CIGS THAT ARE ESTABLISHED WILL LIKELY
REMAIN LOW-END VFR...MAINLY AT KSAV WHERE THE RISK FOR LOW CLOUDS
WILL BE THE GREATEST. WILL CARRY VFR CONDITIONS AT BOTH KCHS/KSAV
FOR THE NEXT 24 HOURS. WILL LIKELY SEE A PERIOD OF GUSTY WINDS IN
THE WAKE OF THE AFTERNOON...POSSIBLY REACHING AS HIGH AS 15-18 KT.
EXTENDED AVIATION OUTLOOK...POSSIBLE FLIGHT RESTRICTIONS IN LIGHT
FOG/MIST LATE AT NIGHT AND IN THE MORNING SUNDAY NIGHT THROUGH
WEDNESDAY.
&&
.MARINE...
TODAY...NORTHEAST WINDS WILL GRADUALLY TURN SOUTHEAST TODAY AS THE
COASTAL TROUGH DRIFTS CLOSER TO THE COAST AND GRADUALLY BECOMES
ABSORBED IN THE BROADER SYNOPTIC FLOW. WINDS WILL GENERALLY REMAIN
10-15 KT THROUGH THE DAY...ALTHOUGH THERE WILL LIKELY BE COME
ENHANCEMENT NEAR THE LAND/SEA INTERFACE AND IN THE CHARLESTON
HARBOR AS THE SEA BREEZE DEVELOPS AND MOVES INLAND. SEAS WILL
RANGE FROM 2-4 FT NEARSHORE WATERS WITH 4-5 FT OFFSHORE WATERS.
TONIGHT...THERE ARE NO CONCERNS TONIGHT WITH SOUTHEAST WINDS
DOMINATING. WINDS WILL REMAIN 10-15 KT WITH SEAS 2-4 FT...
HIGHEST OVER THE GEORGIA OFFSHORE WATERS
MONDAY THROUGH FRIDAY...THE MARINE ZONES WILL REMAIN ALONG THE
WESTERN PERIPHERY OF A LARGE AND FAIRLY STRONG RIDGE OF ATLANTIC
HIGH PRESSURE THROUGH THE UPCOMING WEEK. SOUTHEAST/SOUTH
CIRCULATION AROUND THE HIGH WILL BECOME ENHANCED AT TIMES BY
AFTERNOON/EVENING SEA BREEZE CIRCULATIONS...BUT EXPECT WINDS TO BE
CAPPED AT 10 OR 15 KT. SEAS WILL GENERALLY RANGE FROM 2 TO 4 FT
THROUGH MID WEEK. THE GRADIENT WILL LIKELY TIGHTEN BETWEEN THE
ATLANTIC HIGH AND AN APPROACHING COLD FRONT BY THURSDAY. WINDS
AND/OR SEAS COULD THEREFORE BUILD CLOSE TO ADVISORY LEVELS LATE IN
THE FORECAST PERIOD.
RIP CURRENTS...OPTED TO UPGRADE TO A MODERATE RISK FOR RIP
CURRENTS FOR ALL BEACHES TODAY. WW4 OUTPUT SHOWS 8 TO OCCASIONAL 9
SECOND SWELLS DOMINATING FOR MUCH OF THE DAY. TYBEE ISLAND
LIFEGUARDS REPORTED RIP CURRENTS ALONG WITH SEVERAL ASSISTS AND
ONE RESCUE YESTERDAY AFTERNOON. CONSIDERING SIMILAR CONDITIONS
WILL BE IN PLACE TODAY...THERE IS ENOUGH EVIDENCE TO SUPPORT A
MODERATE RISK...DESPITE THE FAIRLY MODEST ONSHORE WIND REGIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ044-045-
052.
MARINE...NONE.
&&
$$
ST/79
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
410 AM EDT SUN APR 7 2013
...MODERATE RISK FOR RIP CURRENTS TODAY...
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH MID WEEK. A COLD FRONT WILL
APPROACH THE AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THROUGH SUNRISE...LOW CLOUDS HAVE YET TO DEVELOP ACROSS THE AREA
EARLY THIS MORNING. KCLX VWP SHOWS WINDS ALOFT HAVE VEERED MORE
SOUTHERLY AS EXPECTED WHILE AT THE SURFACE WINDS REMAIN LIGHT
NORTHEAST. IT APPEARS ANY ISENTROPIC ASSENT THAT IS OCCURRING IS
JUST NOT STRONG ENOUGH TO PRODUCE MUCH CLOUD COVER YET AND
INCOMING RAP GUIDANCE CONTINUES TO SUGGEST THIS WILL BE THE CASE
THROUGH SUNRISE. HAVE ADJUSTED SKY COVER DOWN TO MOSTLY CLEAR TO
PARTLY CLOUDY AND REMOVED ALL INDICATIONS OF MOSTLY CLOUDY SKIES.
HOWEVER...A BRIEF PERIOD OF MOSTLY CLOUDY CONDITIONS CAN NOT BE
RULED OUT MAINLY ACROSS INTERIOR SOUTHEAST GEORGIA. LOWS FROM THE
MID 40S WELL INLAND TO THE LOWER-MID 50S ALONG THE IMMEDIATE COAST
LOOK ON TRACK.
TODAY...LARGE SOUTHWEST-NORTHEAST ORIENTED HIGH PRESSURE CENTERED
OFF NEW ENGLAND WILL STEADILY SHIFT FARTHER OFFSHORE TODAY AS A
FAIRLY ZONAL FLOW DOMINATES ALOFT. ONGOING WEAK WARM ADVECTION
WILL PUSH H8 TEMPERATURES INTO THE 8-9C RANGE WHICH WILL YIELD
SLIGHTLY WARMER HIGH TEMPERATURES COMPARED TO SATURDAY. LOW-LEVEL
THICKNESSES SCHEMES AND MODEL BUFR SOUNDINGS GENERALLY SUPPORT
HIGHS IN THE LOWER-MID 70S WITH CONSIDERABLY COOLER TEMPERATURES
IN THE LOWER 60S AT THE BEACHES WHERE OCEANIC INFLUENCES WILL BE
THE GREATEST. EXPECT ANOTHER RATHER ROBUST SEA BREEZE CIRCULATION
TO FORM ALONG THE BEACHES LATER TODAY WHICH WILL MOVE STEADILY
INLAND DURING THE AFTERNOON HOURS. THIS WILL CAUSE TEMPERATURES TO
DROP ABOUT 5-8 DEGREES ACROSS THE COASTAL COUNTIES WITH ITS
PASSAGE...SIMILAR TO SATURDAY. WITH THE LACK OF STRATOCUMULUS
THIS MORNING...ITS UNCLEAR EXACTLY HOW MUCH CUMULUS WILL DEVELOP
LATER TODAY AS TEMPERATURES WARM INTO THE 70S. SUSPECT THERE WILL
BE AT LEAST A SHALLOW...SOMEWHAT SCATTERED CUMULUS FIELD AHEAD OF
THE SEA BREEZE SO WILL STICK WITH A PARTLY CLOUDY SKIES CHARACTER
FOR TODAY. SKIES WILL LIKELY CLEAR A BIT IN THE WAKE OF THE SEA
BREEZE AS MORE STABLE AIR IS DRAWN INLAND FROM OFF THE ATLANTIC.
THIS MAY RESULT IN A PERIOD OF MOSTLY SUNNY TO SUNNY SKIES PRIOR
TO SUNSET...MAINLY ACROSS THE COASTAL CORRIDORS. NO RAIN IS
EXPECTED EVEN AS THE COASTAL FRONT DRAWS CLOSER TO THE COAST AND
EVENTUALLY BECOMES ABSORBED IN THE BROADER SYNOPTIC FLOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...THE AREA WILL REMAIN ALONG THE WESTERN FRINGES OF
ATLANTIC HIGH PRESSURE TONIGHT. EXPECT MAINLY CLEAR SKIES TO
DOMINATE WITH SOME PATCHY STRATOCUMULUS POSSIBLY MOVING INLAND
FROM OFF THE ATLANTIC. THE BOUNDARY LAYER SHOULD DECOUPLE FOR MOST
AREA AWAY FROM THE IMMEDIATE COAST A FEW HOURS AFTER SUNSET.
GENERALLY FAVORED THE COOLER SIDE OF GUIDANCE GIVEN THE DECENT
RADIATIONAL SETUP. LOWS WILL RANGE FROM THE LOWER 50S INLAND TO
THE MID 50S ALONG THE IMMEDIATE COAST. A FEW UPPER 40S CAN NOT BE
COMPLETELY RULED OUT...MAINLY IN THE NORMALLY COLDER LOCATIONS
SUCH AS ALLENDALE AND JAMESTOWN. COULD SEE SOME SHALLOW GROUND FOG
FORM AFTER MIDNIGHT...BUT ITS PROBABLY NOT WORTH MENTIONING GIVEN
THE LACK OF ANY SIGNIFICANT IMPACT.
MONDAY AND TUESDAY...THE FORECAST AREA WILL REMAIN ON THE PERIPHERY
OF SURFACE HIGH PRESSURE IN THE ATLANTIC EARLY NEXT WEEK. THE UPPER
LEVEL PATTERN WILL BECOME MORE AMPLIFIED BY TUESDAY...AS A DEEP
TROUGH SHIFTS INTO THE CENTRAL PLAINS AND RIDGING STRENGTHENS ACROSS
THE SOUTHEAST COAST. RISING HEIGHTS ALOFT AND SOUTH/SOUTHEAST FLOW
WILL SUPPORT UNSEASONABLY WARM CONDITIONS EACH AFTERNOON. HIGH
TEMPERATURES INLAND WILL RISE INTO THE UPPER 70S TO LOWER 80S ON
MONDAY...WHILE WARMING SOLIDLY INTO THE LOWER 80S BY TUESDAY. THE
ONSHORE COMPONENT TO THE SURFACE FLOW WILL KEEP COASTAL LOCATIONS
NOTABLY COOLER...SUPPRESSING HIGH TEMPERATURES IN THE LOWER TO MID
70S NEAR THE BEACHES. ALTHOUGH LOW LEVEL MOISTURE WILL BE
INCREASING...AND A SEABREEZE BOUNDARY WILL DEVELOP WITHIN MORE
SUMMER-LIKE CONDITIONS...DECENT SUBSIDENCE SHOULD PREVENT DIURNAL
SHOWER DEVELOPMENT. HAVE THUS CAPPED RAIN CHANCES BELOW 15 PERCENT.
WEDNESDAY...DEEP LAYER RIDGING WILL GRADUALLY SHIFT FARTHER INTO
THE ATLANTIC BY MID WEEK...WHILE THE ROBUST UPPER TROUGH
STRETCHING FROM THE NORTHERN PLAINS TO THE SOUTHWEST STATES MAKES
SOME PROGRESS EASTWARD. THIS SYSTEM WILL PROVIDE THE ENERGY TO
SPAWN A SURFACE LOW AND TRAILING COLD FRONT TO THE WEST OF THE
FORECAST AREA. THE GFS MODEL SOLUTIONS HAVE BEEN CONSISTENTLY MORE
AGGRESSIVE IN BREAKING DOWN THE DEEP RIDGING...DECREASING
SUBSIDENCE ENOUGH TO SUPPORT DIURNAL SHOWER DEVELOPMENT WEDNESDAY
AFTERNOON. PREFER TO LEAN TOWARD A MORE CONSERVATIVE AND SLOWER
SCENARIO...THUS CONTINUING TO KEEP RAIN CHANCES BELOW 15 PERCENT.
WILL ALSO CONTINUE TO INDICATE UNSEASONABLY WARM HIGH
TEMPERATURES...REACHING THE LOWER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE DURING THE AFTERNOON HOURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MEDIUM RANGE MODEL SOLUTIONS MAINTAIN SIGNIFICANT DISCREPANCIES IN
THE TIMING OF A COLD FRONT APPROACHING FROM THE WEST LATE IN THE
WEEK. AN ELONGATED UPPER TROUGH OVER THE CENTRAL PLAINS WEDNESDAY
NIGHT WILL BREAK INTO A MORE SPLIT FLOW FEATURE BY THURSDAY.
SLOWER MODEL SOLUTIONS SUGGEST THE SOUTHERN SHORTWAVE ENERGY WILL
SPIN UP A SECONDARY SURFACE LOW ALONG THE GULF COAST STATES THAT
COULD DELAY THE PROGRESS OF THE FRONTAL SYSTEM. IN ADDITION...THERE
IS SOME QUESTION AS TO THE RESILIENCY OF THE UPPER RIDGE AND
SUBSEQUENT IMPACTS ON PRECIPITATION TIMING AND COVERAGE. UPON
COLLABORATION WITH NEIGHBORING FORECAST OFFICES...PREFER TO LEAN
TOWARD THE SLOWER MODELS SOLUTIONS AT THIS TIME. WILL INTRODUCE A
SLIGHT CHANCE OF RAIN FROM WEST TO EAST AS EARLY AS THURSDAY...YET
SUGGEST THE HIGHEST POTENTIAL FOR SHOWER/THUNDERSTORM COVERAGE
FRIDAY AFTERNOON AND EVENING...WHEN THE SOUTHERN STREAM SHORTWAVE
AND SURFACE LOW LIFT INTO THE AREA. REGARDLESS OF MODEL
SOLUTION...THE UNSEASONABLY WARM CONDITIONS AHEAD OF THE FRONTAL
SYSTEM WILL SUPPORT DECENT INSTABILITY AND SUBSEQUENT THUNDERSTORM
DEVELOPMENT. THIS INSTABILITY...WHEN COMBINED WITH A POTENTIAL 40
TO 50 KT LOW LEVEL JET...COULD ALSO ALLOW THUNDERSTORMS TO BECOME
STRONG AND ORGANIZED. HOWEVER...CONFIDENCE IN SUCH DETAILS THIS
FAR OUT REMAINS LOW...ESPECIALLY CONSIDERING CURRENT MODEL
CONSISTENCY ISSUES.
EXPECT THE COLD FRONT TO HAVE CROSSED THE EAST COAST BY FRIDAY
NIGHT...WITH SURFACE HIGH PRESSURE RAPIDLY REBUILDING FROM THE WEST
IN ITS WAKE. HAVE MAINTAINED JUST A SLIGHT CHANCE FOR
SHOWERS/THUNDERSTORMS INTO EARLY SATURDAY...WITH POPS FALLING
BELOW 15 PERCENT FOR THE REMAINDER OF THE WEEKEND. HIGH
TEMPERATURES WILL BE A FEW DEGREES COOLER FROM FRIDAY AFTERNOON
THROUGH SUNDAY...BECOMING CLOSER TO SEASONAL NORMALS IN THE MID
70S BY THE WEEKEND.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
GENERALLY VFR. INCREASING MOISTURE FROM OFF THE ATLANTIC WILL
LIKELY SUPPORT SOME STRATOCUMULUS THROUGH SUNRISE. ITS STILL
UNCLEAR AT THIS POINT HOW WIDESPREAD THESE CLOUDS WILL BECOME BUT
LATEST RAP DATA SUGGESTS ANY CIGS THAT ARE ESTABLISHED WILL LIKELY
REMAIN LOW-END VFR...MAINLY AT KSAV WHERE THE RISK FOR LOW CLOUDS
WILL BE THE GREATEST. WILL CARRY VFR CONDITIONS AT BOTH KCHS/KSAV
FOR THE NEXT 24 HOURS. WILL LIKELY SEE A PERIOD OF GUSTY WINDS IN
THE WAKE OF THE AFTERNOON...POSSIBLY REACHING AS HIGH AS 15-18 KT.
EXTENDED AVIATION OUTLOOK...POSSIBLE FLIGHT RESTRICTIONS IN LIGHT
FOG/MIST LATE AT NIGHT AND IN THE MORNING SUNDAY NIGHT THROUGH
WEDNESDAY.
&&
.MARINE...
TODAY...NORTHEAST WINDS WILL GRADUALLY TURN SOUTHEAST TODAY AS THE
COASTAL TROUGH DRIFTS CLOSER TO THE COAST AND GRADUALLY BECOMES
ABSORBED IN THE BROADER SYNOPTIC FLOW. WINDS WILL GENERALLY REMAIN
10-15 KT THROUGH THE DAY...ALTHOUGH THERE WILL LIKELY BE COME
ENHANCEMENT NEAR THE LAND/SEA INTERFACE AND IN THE CHARLESTON
HARBOR AS THE SEA BREEZE DEVELOPS AND MOVES INLAND. SEAS WILL
RANGE FROM 2-4 FT NEARSHORE WATERS WITH 4-5 FT OFFSHORE WATERS.
TONIGHT...THERE ARE NO CONCERNS TONIGHT WITH SOUTHEAST WINDS
DOMINATING. WINDS WILL REMAIN 10-15 KT WITH SEAS 2-4 FT...
HIGHEST OVER THE GEORGIA OFFSHORE WATERS
MONDAY THROUGH FRIDAY...THE MARINE ZONES WILL REMAIN ALONG THE
WESTERN PERIPHERY OF A LARGE AND FAIRLY STRONG RIDGE OF ATLANTIC
HIGH PRESSURE THROUGH THE UPCOMING WEEK. SOUTHEAST/SOUTH
CIRCULATION AROUND THE HIGH WILL BECOME ENHANCED AT TIMES BY
AFTERNOON/EVENING SEA BREEZE CIRCULATIONS...BUT EXPECT WINDS TO BE
CAPPED AT 10 OR 15 KT. SEAS WILL GENERALLY RANGE FROM 2 TO 4 FT
THROUGH MID WEEK. THE GRADIENT WILL LIKELY TIGHTEN BETWEEN THE
ATLANTIC HIGH AND AN APPROACHING COLD FRONT BY THURSDAY. WINDS
AND/OR SEAS COULD THEREFORE BUILD CLOSE TO ADVISORY LEVELS LATE IN
THE FORECAST PERIOD.
RIP CURRENTS...OPTED TO UPGRADE TO A MODERATE RISK FOR RIP
CURRENTS FOR ALL BEACHES TODAY. WW4 OUTPUT SHOWS 8 TO OCCASIONAL 9
SECOND SWELLS DOMINATING FOR MUCH OF THE DAY. TYBEE ISLAND
LIFEGUARDS REPORTED RIP CURRENTS ALONG WITH SEVERAL ASSISTS AND
ONE RESCUE YESTERDAY AFTERNOON. CONSIDERING SIMILAR CONDITIONS
WILL BE IN PLACE TODAY...THERE IS ENOUGH EVIDENCE TO SUPPORT A
MODERATE RISK...DESPITE THE FAIRLY MODEST ONSHORE WIND REGIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/79
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
120 AM EDT SUN APR 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH THE MIDDLE OF NEXT WEEK. A COLD
FRONT WILL APPROACH THE AREA LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ADJUSTED LOW TEMPERATURES DOWN IN A SEVERAL AREAS PER GOING
TRENDS. HAVING DOUBTS ON THE DEVELOPMENT OF WIDESPREAD
STRATOCUMULUS AS SOME OF THE VARIOUS GUIDANCE SUGGESTS. LOWERED
SKY COVER A CATEGORY IN SOME AREAS PER LATEST RAP SOUNDINGS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/...
SUNDAY...THE FLOW ALOFT IS PRETTY MUCH ZONAL ACROSS THE LOWER 48
STATES...INCLUDING THE LOCAL ZONES. A LARGE AND ELONGATED RIDGE OF
SURFACE HIGH PRESSURE WILL STRETCH FROM EAST OF NEW ENGLAND TO
ACROSS THE SE STATES AND INTO THE GULF OF MEXICO AND BAY OF
CAMPECHE. THE RESULTING SYNOPTIC FLOW VEERS AROUND TO THE SE AND
SOUTH...WHICH PRODUCES TWO IMPORTANT FACTORS IN THE FORECAST
PROCESS. FIRST IT PROVIDES THE AREA WITH SLIGHTLY WARMER CONDITIONS
THAN TODAY...WHILE IT ALSO ALLOWS FOR A NOTICEABLE INCREASE IN LOWER
LEVEL MOISTURE. AS 850 MB TEMPS CLIMB TO 8-9C AND LOW LEVEL
THICKNESS VALUES RISE TO BETWEEN 1362 AND 1372 METERS FROM NE TO
SW...IT ALLOWS FOR MAX TEMPS TO ACTUALLY RISE ABOVE EARLY APRIL
NORMS. LOWER AND MIDDLE 70S WILL BE FAIRLY UNIFORM...EXCEPT FOR THE
SHORELINE SECTIONS WHERE THE COOLING SEA BREEZE/ONSHORE TRAJECTORIES
WILL LIMIT HIGHS TO ONLY THE MID OR UPPER 60S. THE MAJORITY OF THE
MOISTURE IS TRAPPED BENEATH A STRONG SUBSIDENCE INVERSION AND
RESTRICTED TO THE LOWEST 1-1.5 MILES OF THE ATMOSPHERE. WITH THE LOW
AND MID LEVEL LAPSE RATES STEEPENING QUICKLY IN THE MORNING...WE/RE
CONFIDENT THAT THIS WILL PRODUCE PERIODS OF STRATOCUMULUS AND FLAT
CUMULUS CLOUD COVER THROUGHOUT THE DAY...EQUATING TO A PARTLY TO
PERIODICALLY MOSTLY CLOUDY SKY COVER FORECAST. THERE ARE HINTS AT A
COUPLE OF BRIEF SHOWERS FORMING ALONG THE INLAND PENETRATING SEA
BREEZE WITH WEAK ISENTROPIC LIFT AND SOME UPWARD OMEGA FIELDS. BUT
GIVEN LARGE DEW POINT DEPRESSIONS MOSTLY 15 DEGREES OR MORE...POPS
WILL BE LIMITED TO ONLY A SILENT 10 PERCENT.
SUNDAY NIGHT...ATLANTIC RIDGING WILL PERSIST OVERHEAD FROM THE EAST
AND NE...WITH ZONAL FLOW UPSTAIRS. A WARM SE TO SOUTH SYNOPTIC FLOW
AND AT LEAST SOME LOWER STRATOCUMULUS AND/OR STRATUS WILL PREVENT
TEMPS FROM FALLING ANY LOWER THAN THE LOWER OR MIDDLE 50S INLAND
FROM THE INTRACOASTAL...WITH A FEW UPPER 50S ON THE ISLANDS. FOG
COULD BECOME A REALITY WITH HIGHER DEW POINTS...CONDENSATION
PRESSURE DEFICITS FALLING TO 30-50 MB AND GEOSTROPHIC WINDS 10 KT
OR LESS. HOWEVER...WE/LL BE HARD-PRESSED TO REACH OUR CROSS-OVER
TEMPS IN MANY AREAS...THUS NO MORE THAN PATCHY FOG INLAND WELL
LATE.
MONDAY...THE MID AND UPPER PATTERN WILL START TO UNDERGO SOME
CHANGES IN THE LARGER SCALE...AS A MORE AMPLIFIED TROUGH DEVELOPS
OUT WEST. THE QUASI-ZONAL FLOW OVERHEAD LOCALLY WILL TRANSITION TO
SHORT WAVE RIDGING DURING THE SECOND HALF OF THE DAY...RESULTING IN
SOME NOTICEABLE MID LEVEL HEIGHT RISES. THAT ALONG WITH A CONTINUED
INCREASE IN BOTH 850 MB TEMPS AND LOW LEVEL THICKNESSES WILL YIELD
AN EVEN WARMER DAY. HIGHS WILL MAX OUT WITHIN A DEGREE OR TWO EITHER
SIDE OF 80...ALTHOUGH THE ONSHORE FETCH AND SEA BREEZE CIRCULATION
HOLDS COASTAL AREAS TO ONLY THE UPPER 60S TO PERHAPS 70. THE
SYNOPTIC PATTERN WILL EXPERIENCE THE FORMATION OF A TYPICAL WARM
SEASON RIDGE OF BERMUDA HIGH PRESSURE...THAT STRETCHES ACROSS MOST
OF THE EAST AND SE PARTS OF THE NATION. THE SOUTHERLY LOW LEVEL FLOW
AROUND THIS FEATURE WILL CONTINUE TO ADVECT SOME LOW LEVEL MOISTURE
INTO THE REGION...BUT WITH THE LARGE SCALE SINKING AIR WE/LL BE
HARD-PRESSED TO OBTAIN ANY SHOWER ACTIVITY ALONG THE SEA BREEZE.
MONDAY NIGHT...ODDS FAVOR A GREATER POTENTIAL FOR FOG AS
CONDENSATION PRESSURE DEFICITS LOWER TO AROUND 10-30 MB...DEW POINTS
ARE EVEN HIGHER AND CROSS-OVER TEMPS WILL BE ACHIEVED IN MANY
LOCALES. WEAK WARM ADVECTION WILL LIMIT MINIMUM TEMPS TO ONLY THE
MID AND UPPER 50S MOST COMMUNITIES.
TUESDAY...A MORE AMPLIFIED SCENARIO WILL UNFOLD ALOFT...WITH A DEEP
POSITIVELY TILTED TROUGH IN THE ROCKIES TO BAJA CALIFORNIA...WHILE
INCREASED RIDGING FORMS IN THE EAST. MID LEVEL HEIGHTS IN SOUTHERN
SC AND SE GA RISE TO AROUND 5840 METERS...WITH A CONTINUED WARMING
THROUGHOUT MUCH OF THE VERTICAL. BERMUDA HIGH PRESSURE IS AGAIN
FIRMLY IN CONTROL...AND WITH ONLY LIMITED MOISTURE CONFINED IN THE
LOWER LAYERS AND A STRONG SUBSIDENCE INVERSION OUR RAIN CHANCES ARE
CLOSE TO ZERO. THERE IS ONLY A SUBTLE INCREASE IN LOW LEVEL
THICKNESS...SO MAX TEMPS WILL BE A DEGREE OR TWO WARMER THAN ON
MONDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DEEP LAYER RIDGING WILL SHIFT FARTHER INTO THE ATLANTIC WEDNESDAY
AND THURSDAY. THE UPPER TROUGH FAR TO THE WEST WILL ALSO RAPIDLY
SWING INTO THE MISSISSIPPI VALLEY AND SHIFT A COLD FRONT THROUGH
THE OHIO/TENNESSEE VALLEYS. THERE REMAINS CONSIDERABLE TIMING
DIFFERENCES IN MODEL SOLUTIONS REGARDING THE FRONTAL PASSAGE...
WHICH COULD OCCUR AS EARLY AS THURSDAY AFTERNOON OR AS LATE AS
FRIDAY NIGHT. DUE TO THIS UNCERTAINTY...PREFER TO KEEP MUCH OF THE
LONG RANGE FORECAST AS PERSISTENCE UNTIL MODELS COME INTO BETTER
AGREEMENT. HAVE THUS REMAINED RATHER GENERIC...INDICATING RAIN
CHANCES IN THE 20 TO 30 PERCENT RANGE THURSDAY AND FRIDAY. WITH
UNSEASONABLY WARM CONDITIONS CONTINUING PRIOR TO FRONTAL
PASSAGE...THERE WILL BE ENOUGH TIME FOR LOW LEVEL INSTABILITY TO
DEVELOP ACROSS THE AREA AS THE FRONT CROSSES THE REGION. THIS
UNSTABLE AIR...WHEN COMBINED WITH AN IMPRESSIVE 40 TO 50 KT LOW
LEVEL JET...COULD SUPPORT STRONG THUNDERSTORMS LATE THIS WEEK.
CONDITIONS BY SATURDAY COULD BE IMPROVING...AS EVEN THE SLOWEST
MODEL SOLUTIONS HAVE THE FRONT MOVING OFF THE COAST BY THE
AFTERNOON HOURS. EXPECT A SLIGHT COOL DOWN TOWARD SEASONAL NORMALS
IN THE MID 70S BEHIND THE FRONT LATE IN THE PERIOD.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
GENERALLY VFR. INCREASING MOISTURE FROM OFF THE ATLANTIC WILL
LIKELY SUPPORT SOME STRATOCUMULUS THROUGH SUNRISE. ITS STILL
UNCLEAR AT THIS POINT HOW WIDESPREAD THESE CLOUDS WILL BECOME BUT
LATEST RAP DATA SUGGESTS ANY CIGS THAT ARE ESTABLISHED WILL LIKELY
REMAIN LOW-END VFR...MAINLY AT KSAV WHERE THE RISK FOR LOW CLOUDS
WILL BE THE GREATEST. WILL CARRY VFR CONDITIONS AT BOTH KCHS/KSAV
FOR THE NEXT 24 HOURS. WILL LIKELY SEE A PERIOD OF GUSTY WINDS IN
THE WAKE OF THE AFTERNOON...POSSIBLY REACHING AS HIGH AS 15-18 KT.
EXTENDED AVIATION OUTLOOK...POSSIBLE FLIGHT RESTRICTIONS IN LIGHT
FOG/MIST LATE AT NIGHT AND IN THE MORNING SUNDAY NIGHT THROUGH
WEDNESDAY.
&&
.MARINE...
THE MAIN CONCERN OVERNIGHT IS SEA HEIGHTS OVER OUR OUTER GEORGIA
WATERS RUNNING POSSIBLY NEAR ADVISORY LEVELS FOR A WHILE. STEADY
NE-E FETCH AND SEAS OBSERVED GREATER THAN MODEL WAVE GUIDANCE WELL
OFF THE S CAROLINA COAST ARE PROBABLY TIPS WE HAVE SOME 6 FOOTERS
OUT THERE CLOSER TO THE GULF STREAM IN AMZ374. MODELS ALLOW THE
FLOW TO LAY DOWN OVERNIGHT AND WE HAVE OPTED NOT TO RAISE A SMALL
CRAFT ADVISORY DURING THIS EVENING GIVEN FORECAST MODEL TRENDS.
STILL A NICE SWELL COMPONENT AND 4-5 FT LOOKING COMMON OVERNIGHT
BEYOND 20 NM. OTHERWISE...FLOW LOCKED NE TONIGHT BY THE COLDER
SHELF WATERS WITH SPEEDS 15 KT OR LESS AND SEAS 3 TO 4 FT.
THE LOCAL WATERS WILL LIE UNDER THE WESTERN PORTION OF A LARGE
AND FAIRLY STRONG RIDGE OF ATLANTIC HIGH PRESSURE THROUGHOUT THE
UPCOMING WEEK. THE ANTICYCLONIC SE AND SOUTH CIRCULATION AROUND
THE HIGH WILL BECOME ENHANCED AT TIMES BY AFTERNOON/EVENING SEA
BREEZE CIRCULATIONS...BUT NOTHING MORE THAN ABOUT 10 OR 15 KT
WINDS AND 2-4 FOOT SEAS THROUGH WEDNESDAY. BY THURSDAY THERE DOES
APPEAR TO BE SOME TIGHTENING OF THE GRADIENT BETWEEN THE HIGH AND
AN APPROACHING COLD FRONT...AND WINDS AND/OR SEAS COULD BUILD
CLOSE TO ADVISORY LEVELS LATE IN THE FORECAST PERIOD.
RIP CURRENTS...DESPITE WATER TEMPS ONLY NEAR 60 AND AIR TEMPS NOT
MUCH HIGHER...THERE ARE STILL PEOPLE FLOCKING TO THE BEACH. AND SOME
ARE VENTURING INTO THE SURF...WITH REPORTS OF RIP CURRENTS AND
RESCUES AT TYBEE BEACH EARLIER TODAY. WITH ONSHORE WINDS AT 10-15
MPH AND AROUND 2 FOOT SWELLS EVERY 8 SECONDS WE/LL BE AT THE
HIGH-END RANGE OF THE LOW RISK OF RIP CURRENTS SUNDAY. IF SWELLS ARE
ABLE TO OBTAIN 3 FEET...A MODERATE RISK WOULD BE REQUIRED. BEACH
GOERS ARE REMINDED THAT EVEN DURING A LOW RISK THAT RIP CURRENTS CAN
STILL OCCUR.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 AM CDT SUN APR 7 2013
.DISCUSSION...
912 PM CDT
SHOWERS CONTINUE TO MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HOWEVER...A CLUSTER OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED OVER
THE PAST COUPLE HOURS ACROSS EASTERN IOWA. THIS ACTIVITY IS FIRING
JUST AHEAD OF A SURFACE COLD FRONT IN AN AREA OF INCREASED ASCENT
AHEAD OF A RATHER STOUT MID LEVEL SHORT WAVE...CURRENTLY NOTED IN
THE WATER VAPOR IMAGERY MOVING EASTWARD ACROSS SOUTHEASTERN IOWA. THE
00 UTC SOUNDING OUT OF KDVN INDICATES THAT THE AIRMASS IN WHICH THIS
ACTIVITY IS DEVELOPING IN POSSES DECENT MID LEVEL LAPSE RATES.
HOWEVER...OVERALL INSTABILITY IS RATHER LACK LUSTER...WITH MUCAPE
VALUES ONLY UP TO AROUND 100 J/KG. IN SPITE OF THIS...THE STRONGER
FORCING FOR ASCENT COMPLEMENTS OF THE MID LEVEL WAVE AND MOISTURE
CONVERGENCE IN THE LOWER LEVELS...IS ABLE TO TAKE ADVANTAGE OF THE
STEEP LAPSE RATES TO RESULT IN THUNDERSTORMS. THIS ACTIVITY WILL
LIKELY MAINTAIN ITSELF FOR THE NEXT FEW HOURS AS IT PUSHES EASTWARD
ACROSS NORTHERN ILLINOIS. THERE COULD EVEN BE SOME SMALL HAIL AND
SOME GUSTY WINDS IN SOME OF THE STRONGEST STORMS GIVEN THE DRIER AIR
IN THE LOWEST FEW THOUSAND FEET. THIS ACTIVITY SHOULD END OVERNIGHT
WITH WINDS BECOMING WESTERLY IN THE WAKE OF THE FRONTAL PASSAGE.
KJB
//PREV DISCUSSION...
259 PM CDT
THERE ARE NUMEROUS CHALLENGES WITH THE FORECAST AS THE PATTERN
TRANSITIONS TO A MORE ACTIVE ONE...BEGINNING WITH SHOWERS AND
SOME SPORADIC THUNDER THIS EVENING AND THEN CARRYING THROUGH THE
MIDDLE OF NEXT WEEK. IN ADDITION...THE LIKELY LOCATION OF THE
AREA RELATIVE TO SYNOPTIC FEATURES WILL ALLOW FOR TEMPERATURES TO
BE HEAVILY DEPENDENT ON CLOUD COVER AND RAIN...ALONG WITH LAKE
INDUCED COOLING AT LEAST A FEW OF THE UPCOMING SEVERAL DAYS.
NEAR TERM INTO TONIGHT...A FAST PACED BUT MORE AMPLIFIED UPPER
LEVEL PATTERN IS ESTABLISHED OVER THE CENTRAL U.S. THIS AFTERNOON
WITH A WELL-DEFINED UPPER WAVE ON WATER VAPOR ADVANCING EASTWARD
FROM WESTERN IA. A 1000 MB SURFACE LOW REFLECTION ACROSS SOUTHERN
MN HAS DEVELOPED AND HELPED TO ESTABLISH STRONG RETURN FLOW WITH
WIND GUSTS TO 40 TO 45 MPH AT SEVERAL SITES. THESE WINDS SHOULD
DIMINISH GRADUALLY THROUGH THE EVENING HOURS.
MOISTURE RETURN HAS STRUGGLED HOWEVER...BOTH AT THE SURFACE AND IN
THE DEEP LAYER PER OBSERVATIONS AND PWAT ANALYSIS AND IS A REASON
SHOWER COVERAGE IS LIKELY TO BE MORE LIMITED THAN IT COULD BE
GIVEN THE UPPER FORCING AHEAD OF THIS WAVE...AND IT WILL TAKE SOME
TIME FOR THE VERY DRY LOWER ATMOSPHERE TO SATURATE. A NARROW
CORRIDOR OF 700-900 MB MOISTURE TRANSPORT ALONG A MID-LEVEL JET
HAS STILL HELPED TO INCREASE ECHOES UPSTREAM DURING THE FIRST HALF
OF THE AFTERNOON AND THIS WILL LIKELY BE JUST ENOUGH TO CONTINUE
DOING SUCH WITH STEEPENING MID-LEVEL LAPSE RATES IN CONCERT WITH
THE NARROW MOISTURE CONVERGENCE. MOST OF THE HIGH-RES CONVECTIVE
ALLOWING MODELS PREDICT AN INCREASE IN CONVECTIVE-TYPE ECHOES
ACROSS NORTH CENTRAL IL BETWEEN 23Z AND 03Z SHIFTING EASTWARD AND
FADING SLOWLY THROUGH EARLY OVERNIGHT AS THE FRONT SHIFTS EAST.
WITH SEVERAL OF THESE GUIDANCE MEMBERS INDICATING HIGHER
REFLECTIVITY AND A NARROW CORRIDOR OF 200-400 J/KG OF MUCAPE PER
THE RAP ALONG THE FRONT...WOULD EXPECT A FEW STORMS WITHIN THE
GENERAL SHOWERS. HAVE ADAPTED HOURLY POPS THROUGH THIS EVENING
PERIOD OF THE FORECAST. AS PREVIOUS FORECAST DID KEEP MOST OF
TONIGHTS TEMPERATURE DROP AFTER THE FRONTAL PASSAGE FROM WEST TO
EAST.
SUNDAY...HIGH PRESSURE STILL LOOKS TO BRIEFLY PREVAIL FOR THIS
PERIOD. THE MOST NOTEWORTHY ASPECT ABOUT THIS IS IT LOOKS TO LINE
UP DOWN THE AXIS OF LAKE MICHIGAN BY MIDDAY AND ALLOW FOR A FAIRLY
STOUT LAKE BREEZE. THIS WILL BE AIDED BY THE FACT THAT
TEMPERATURES SHOULD MODERATE NICELY ON SUNDAY OVER LAND DUE TO
ONLY A SMALL WINDOW OF COLD AIR ADVECTION BEHIND THE FRONT TONIGHT
AND A DRY AIR MASS AND PREDICTED SUNSHINE DURING SUNDAY. THE
TEMPERATURE AND PRESSURE DIFFERENCES WITHIN A LIGHT WIND FIELD
SHOULD DRIVE A STRONG LAKE BREEZE...AND THE AFTERNOON TEMPERATURE
DROP FOR DOWNTOWN CHICAGO AND OTHER NEAR LAKE AREAS MAY BE AS MUCH
AS 15 DEGREES.
SUNDAY NIGHT AND MONDAY...AN ACTIVE WEST-TO-EAST PACIFIC JET OVER
120 KT AS SEEN ON HEMISPHERIC WATER VAPOR TODAY WILL DIG ITS WAY
INTO THE WESTERN U.S. WITH TROUGH DEVELOPMENT AND UPSTREAM
SOUTHWEST FLOW OVER THE MIDWEST. A LEAD IMPULSE IN THIS FLOW IS
WELL PREDICTED ON GUIDANCE TO PASS OVER THE AREA DURING LATE
SUNDAY NIGHT INTO MONDAY MORNING. THIS LOOKS TO TIGHTEN AN UPPER
LEVEL WARM FRONT AND ALLOW FOR SATURATED ISENTROPIC LIFT FOR RAIN
SHOWERS. ELEVATED INSTABILITY DOES INCREASE AS THE WARM NOSE
BUILDS IN WITHIN THE LOWER LEVELS...AND START THUNDER IN THIS
FORECAST PERIOD ITS TOO TOUGH TO DISCERN A PERIOD WHERE THERE
WOULD NOT BE A THUNDER CHANCE ALL THE WAY THROUGH WEDNESDAY NIGHT.
IN THE WAKE OF THIS LEAD IMPULSE HEIGHTS LOOK TO BUILD ON MONDAY
AS THE PRIMARY TROUGH DEVELOPS. ITS A LITTLE INTERESTING AS THERE
SHOULD BE A SURFACE WARM FRONT...POSSIBLY DIABATICALLY
ENHANCED...LAID OUT SOMEWHERE IN THE CENTRAL IL TO NORTHERN IL
REGION. THE ONLY THING IS WITH SHORT WAVE RIDGING HINTED AT THIS
FEATURE APPEARS TO BE FAIRLY BENIGN...BUT SOMETHING TO KEEP AN
EYE ON.
MIDWEEK...AN ACTIVE PERIOD HERE AS PROLONGED SURFACE CYCLOGENESIS
BEGINS OVER THE SOUTHERN PLAINS MONDAY NIGHT AND CONTINUES THROUGH
TUESDAY WITH THE SURFACE WAVE ADVANCING ENE ON WED. MODEL
GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THIS...LATCHING MORE
ONTO AN EC SOUTHERN SOLUTION. HAVE CONTINUED TO LEAN THAT WAY WITH
THE FORECAST WHICH MEANS INHIBITING TEMPERATURES ON WHAT COULD BE
GIVEN 850MB TEMPERATURES CLIMBING TO 8C-12C...ESPECIALLY NORTH OF
I-80. WITH FLOW OFF THE LAKE TUESDAY AND WEDNESDAY DUE TO THE LOW
BEING SOUTHWEST OF THE AREA...TEMPERATURES NEAR THE LAKE WILL
REMAIN COOLER. ALSO THIS FORECAST PATTERN MEANS LIKELY SEVERAL
BOUTS OF PRECIP WITH THE PROXIMITY OF THE ELEVATED WARM/STATIONARY
FRONT. THE 06.12 GFS AND EC RUNS BOTH HAVE OVER TWO AND A HALF
INCHES OF RAIN FORECAST AREA WIDE FROM SUNDAY NIGHT THROUGH
THURSDAY. WHILE IT IS CHALLENGING TO FOCUS ANY WINDOW FOR
CATEGORICAL POPS...IT WOULD SEEM WEDNESDAY AND WEDNESDAY NIGHT
WOULD BE THE MOST FAVORED PERIODS FOR STRONGER DYNAMIC FORCING AND
POSSIBLY MORE ROBUST ELEVATED CONVECTION WITH THE LARGE SCALE
UPPER TROUGH MOVING EASTWARD. COOLING BEHIND THE FRONT LOOKS
SOMEWHAT STRONG AND THERE IS A POTENTIAL TO SEE SOME MIX IN THE
WAKE OF THE FRONT...BUT CONFIDENCE IS VERY LOW ON HOW THIS SYSTEM
WILL EVOLVE AS IT LIFTS OUT.
BEYOND...HAVE GONE PRIMARILY WITH A MODEL CONSENSUS AT THE END OF
NEXT WEEK AS THE UPPER FLOW PATTERN WORKS FROM BRIEFLY NORTHWEST
BACK TO WEST. TEMPERATURES SHOULD GRADUALLY MODERATE BUT
CONFIDENCE IS LOW ON PRECIP CHANCES AS THE PATTERN STILL LOOKS
DISTURBED.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS OVERNIGHT INTO SUNDAY MORNING
* WIND SHIFT TO EASTERLY SUNDAY AFTERNOON
IZZI
//DISCUSSION...UPDATED 06Z...
COLD FRONT MOVING THROUGH THE REGION AT THIS TIME WITH SHRA/TSRA
MOVING EAST OF THE REGION. EXPANDING BANK OF STRATUS HAS BEEN
NOTED ON SATELLITE IMAGERY UPSTREAM OVER WI/IA INTO NW IL WITH
GUIDANCE SUGGESTING THIS SHOULD CONTINUE TO EXPAND EAST INTO THE
TERMINALS OVERNIGHT. DOES APPEAR THAT MIXING/HEATING SHOULD HELP
ERODE THE STRATUS SUNDAY MORNING...THOUGH TIMING OF SCATTERING OUT
CIGS IS UNCERTAIN. WESTERLY WINDS SHOULD GUST OCCASIONALLY TO
15-20KT OVERNIGHT BEFORE EASING SUNDAY MORNING. PRESSURE FALLS
OVER THE PLAINS EXPECTED TO RESULT IN AN ABRUPT SHIFT TO EASTERLY
WINDS SUNDAY EVENING...WITH THE TIMING OF THAT WIND SHIFT LIKELY A
BIT EARLIER AT ORD/MDW/GYY AS COLLAPSING GRADIENT IN THE AFTERNOON
SHOULD ALLOW FOR ROBUST LAKE BREEZE DEVELOPMENT. NEXT DISTURBANCE
LIKELY TO APPROACH THE REGION TOWARD THE END OF OR JUST BEYOND
THE ORD 30 TAF HOUR PERIOD WITH ADDITIONAL SHRA/TSRA EXPECTED AT
THAT TIME.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN LOW END MVFR CIGS OVERNIGHT INTO SUN
AM
* LOW-MEDIUM CONFIDENCE ON TIMING OF IMPROVEMENT TO VFR SUNDAY
MORNING
* HIGH CONFIDENCE ON WIND SHIFT TO EAST SUN PM
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SHRA/TSRA LIKELY EARLY. MVFR/BRIEF IFR POSSIBLE EARLY.
TUESDAY THROUGH THURSDAY NIGHT...PERIODIC CHANCE FOR SHRA/TSRA.
PERIODIC MVFR CIGS/VSBY LIKELY WITH BRIEF IFR POSSIBLE.
FRIDAY...PROBABLE VFR.
MDB
&&
.MARINE...
258 AM CDT
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION TODAY WITH WINDS
SUBSIDING FAIRLY QUICKLY...BEFORE DEVELOPING LAKE BREEZE CIRCULATION
GETS A BOOST FROM GRADUALLY INCREASING SYNOPTIC EASTERLY GRADIENT
THIS AFTERNOON. EASTERLY WINDS LIKELY TO FRESHEN UP LATE TONIGHT
INTO MONDAY MORNING...ESPECIALLY SOUTHERN PORTIONS OF THE LAKE.
FRONT WILL ATTEMPT TO MOVE NORTH MONDAY...BUT MAY GET HUNG UP ALONG
OR JUST OFFSHORE WITH MORE OF AN EAST OR SOUTHEAST WIND LIKELY OVER
OPEN WATERS. SURGE OF HIGHER DEWPOINTS OVER THE COLD LAKE WITH THE
FRONT NEARBY COULD RESULT IN SOME DENSE MARINE FOG MONDAY NIGHT. FOG
SHOULD DISSIPATE TUESDAY ASSUMING THE NORTHEAST WINDS INCREASE AS
FORECAST. THERE REMAINS SOME DISAGREEMENT AMONG THE MODELS WITH
REGARDS TO FRONTAL PLACEMENT...BUT THE MOST RELIABLE MODELS ARE
GENERALLY KEEPING FRONT SOUTH OF THE LAKE MONDAY NIGHT THROUGH END
OF THE WEEK WITH FAIRLY STRONG NORTHEASTERLY FLOW EXPECTED TO
GENERALLY PREVAIL.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
246 AM CDT SUN APR 7 2013
.DISCUSSION...
ISSUED 245 AM CDT SUN APR 7 2013
COLD FRONT HAS PUSHED THROUGH ABOUT THE NORTHWEST HALF OF THE CWA
AS OF 2 AM...EXTENDING ROUGHLY FROM BLOOMINGTON TO JACKSONVILLE.
NARROW BAND OF SHOWERS ALONG I-70 IS WHAT IS LEFT FROM THE PRE-
FRONTAL CONVECTION WHICH BROUGHT SOME LOCALLY HEAVY SHOWERS LAST
EVENING ACROSS THE NORTHERN CWA. LARGE STRATUS/STRATOCUMULUS DECK
BEHIND THE FRONT HAS BEEN OOZING SOUTHWARD PER FOG CHANNEL
SATELLITE IMAGERY AND HAS REACHED MARSHALL COUNTY...BUT HAS NOT
MADE MUCH FURTHER SOUTHWARD PROGRESSION OVER THE LAST COUPLE
HOURS.
TIMING OF RAIN CHANCES OVER THE NEXT FEW DAYS CONTINUES TO BE A
CHALLENGE...ALONG WITH THE WARM TEMPERATURES.
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...
LATEST MODEL GUIDANCE SHOWING WINDS ALREADY SWINGING BACK TO THE
SOUTHEAST BY AFTERNOON ACROSS MUCH OF THE FORECAST AREA...WITH THE
BOUNDARY LIFTING BACK INTO NORTHERN ILLINOIS OVERNIGHT. MOST OF
THE CWA SHOULD BE ABLE TO REACH 70 DEGREES EXCEPT FOR PERHAPS THE
NORTH...ALTHOUGH A FASTER FRONTAL PASSAGE WOULD ALLOW SUCH
TEMPERATURES THERE AS WELL. CURRENTLY LOOKS LIKE THE DAYTIME
SHOULD BE DRY WITH PERHAPS A COUPLE SHOWERS SOUTH OF I-70 LATE
AFTERNOON...WITH NEXT SURGE OF PRECIPITATION SPREADING IN FROM THE
SOUTHWEST IN THE EVENING AHEAD OF THE NEXT SHORTWAVE IN THE
PLAINS. HAVE RAMPED RAIN CHANCES UP INTO THE CATEGORICAL RANGE OF
NEAR 80 PERCENT ALONG AND WEST OF THE ILLINOIS RIVER AFTER
MIDNIGHT...WITH LIKELY POPS IN MOST OTHER AREAS NORTH OF I-70.
MUCH OF THE RAIN SHOULD EXIT THE AREA MONDAY MORNING...ALLOWING
TEMPS TO RISE BACK TO AROUND 70 WITH A DECENT SOUTHERLY FLOW.
UPPER LOW CURRENTLY SPINNING WEST OF BRITISH COLUMBIA SHOULD DROP
SOUTHEASTWARD INTO THE 4-CORNERS REGION BY MONDAY EVENING.
EVENING MODELS COMING INTO SOMEWHAT BETTER AGREEMENT WITH THE
EVOLUTION OF THIS FEATURE THROUGH THE MIDDLE OF THE WEEK...LIFTING
IT NORTHWARD TO NEAR SOUTH DAKOTA BY WEDNESDAY MORNING WITH A
SURFACE LOW TRACKING NORTHEAST INTO IOWA. CONVECTION EXPECTED TO
INCREASE AGAIN MONDAY NIGHT AND WANE TUESDAY AFTERNOON...BEFORE
RAMPING UP AGAIN AS THE MAIN COLD FRONT APPROACHES. HAVE GONE WITH
LIKELY POPS ACROSS THE WEST TUESDAY NIGHT...EVERYWHERE
WEDNESDAY...AND INCREASED THEM TO CATEGORICAL FROM I-57 EAST
WEDNESDAY EVENING AS THE FRONT PASSES. IN TERMS OF SEVERE
POTENTIAL...THE FRONT WILL BE CROSSING DURING A FAVORABLE TIME OF
THE DAY ON WEDNESDAY...WITH MUCAPES INCREASING TO AROUND 1500
J/KG WEDNESDAY AFTERNOON IN THE EASTERN CWA AND LOW-LEVEL WINDS
RAMPING UP TO AROUND 45 KNOTS AT 925 MB. LATEST SPC DAY3
CONVECTIVE OUTLOOK DOES SPREAD SLIGHT CHANCES OF SEVERE WEATHER
ACROSS THE WESTERN CWA WITH SLIGHTLY LOWER CHANCES ACROSS THE
EAST. FORECAST SOUNDINGS WOULD FAVOR MORE OF A WIND THREAT THIS
FAR EAST WITH UNIDIRECTIONAL WIND PROFILES IN THE LOWER LEVELS.
LONG TERM...THURSDAY THROUGH SATURDAY...
LINGERING SHOWERS ON THURSDAY WILL DECREASE FROM WEST TO EAST AS
THE FRONT PULLS AWAY. HOWEVER...LATEST GFS AND ECMWF MODELS SWING
THE REMAINING UPPER LOW THROUGH IOWA AND WISCONSIN...SO SOME
POTENTIAL FOR COLD-CORE SHOWERS CONTINUES MAINLY ACROSS THE
NORTHERN CWA INTO AFTERNOON...ALTHOUGH BEST CHANCES WILL BE CLOSER
TO THE LOW. THE REMAINDER OF THE WEEK WILL MAINLY BE QUIET...AS
HIGH PRESSURE SLOWLY PUSHES EASTWARD THROUGH THE REGION. WILL SEE
A COUPLE OF COOL DAYS THURSDAY AND FRIDAY...WITH TEMPERATURES
FRIDAY MORNING GETTING CLOSE TO FREEZING ACROSS THE NORTHWEST CWA.
GEELHART
&&
.AVIATION...
ISSUED 1154 PM CDT SAT APR 6 2013...FOR THE 06Z TAFS
SOME SHOWERS MAY AFFECT CMI FOR THE FIRST HALF HOUR OF THE TAF
PERIOD...OTHERWISE THE TERMINAL SITES SHOULD REMAIN DRY OVER
THE NEXT 24 HOURS.
THE COLD FRONT WILL PASS ACROSS DEC/CMI OVER THE NEXT HOUR OR
TWO...SO WINDS SHOULD DIMINISH FROM STRONG SOUTH TO LIGHTER
SOUTHWEST AROUND 12-14KT. LATER TONIGHT ALL TAF SITES SHOULD SEE
WEST WINDS AROUND 10KT.
SOME MVFR CLOUDS ARE EXPECTED TO APPROACH OUR NORTHERN
COUNTIES...WITH PIA AND BMI POSSIBLY SEEING SOME OF THAT. LIGHT
FOG MAY EVEN AFFECT PIA AND BMI. I ADDED A TEMPO FOR BKN015 FOR
12Z TO 15Z TO MATCH THE HRRR OUTPUT FOR THAT TIME FRAME.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1231 AM CDT SUN APR 7 2013
.DISCUSSION...
912 PM CDT
SHOWERS CONTINUE TO MOVE ACROSS NORTHERN ILLINOIS THIS EVENING.
HOWEVER...A CLUSTER OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED OVER
THE PAST COUPLE HOURS ACROSS EASTERN IOWA. THIS ACTIVITY IS FIRING
JUST AHEAD OF A SURFACE COLD FRONT IN AN AREA OF INCREASED ASCENT
AHEAD OF A RATHER STOUT MID LEVEL SHORT WAVE...CURRENTLY NOTED IN
THE WATER VAPOR IMAGERY MOVING EASTWARD ACROSS SOUTHEASTERN IOWA. THE
00 UTC SOUNDING OUT OF KDVN INDICATES THAT THE AIRMASS IN WHICH THIS
ACTIVITY IS DEVELOPING IN POSSES DECENT MID LEVEL LAPSE RATES.
HOWEVER...OVERALL INSTABILITY IS RATHER LACK LUSTER...WITH MUCAPE
VALUES ONLY UP TO AROUND 100 J/KG. IN SPITE OF THIS...THE STRONGER
FORCING FOR ASCENT COMPLEMENTS OF THE MID LEVEL WAVE AND MOISTURE
CONVERGENCE IN THE LOWER LEVELS...IS ABLE TO TAKE ADVANTAGE OF THE
STEEP LAPSE RATES TO RESULT IN THUNDERSTORMS. THIS ACTIVITY WILL
LIKELY MAINTAIN ITSELF FOR THE NEXT FEW HOURS AS IT PUSHES EASTWARD
ACROSS NORTHERN ILLINOIS. THERE COULD EVEN BE SOME SMALL HAIL AND
SOME GUSTY WINDS IN SOME OF THE STRONGEST STORMS GIVEN THE DRIER AIR
IN THE LOWEST FEW THOUSAND FEET. THIS ACTIVITY SHOULD END OVERNIGHT
WITH WINDS BECOMING WESTERLY IN THE WAKE OF THE FRONTAL PASSAGE.
KJB
//PREV DISCUSSION...
259 PM CDT
THERE ARE NUMEROUS CHALLENGES WITH THE FORECAST AS THE PATTERN
TRANSITIONS TO A MORE ACTIVE ONE...BEGINNING WITH SHOWERS AND
SOME SPORADIC THUNDER THIS EVENING AND THEN CARRYING THROUGH THE
MIDDLE OF NEXT WEEK. IN ADDITION...THE LIKELY LOCATION OF THE
AREA RELATIVE TO SYNOPTIC FEATURES WILL ALLOW FOR TEMPERATURES TO
BE HEAVILY DEPENDENT ON CLOUD COVER AND RAIN...ALONG WITH LAKE
INDUCED COOLING AT LEAST A FEW OF THE UPCOMING SEVERAL DAYS.
NEAR TERM INTO TONIGHT...A FAST PACED BUT MORE AMPLIFIED UPPER
LEVEL PATTERN IS ESTABLISHED OVER THE CENTRAL U.S. THIS AFTERNOON
WITH A WELL-DEFINED UPPER WAVE ON WATER VAPOR ADVANCING EASTWARD
FROM WESTERN IA. A 1000 MB SURFACE LOW REFLECTION ACROSS SOUTHERN
MN HAS DEVELOPED AND HELPED TO ESTABLISH STRONG RETURN FLOW WITH
WIND GUSTS TO 40 TO 45 MPH AT SEVERAL SITES. THESE WINDS SHOULD
DIMINISH GRADUALLY THROUGH THE EVENING HOURS.
MOISTURE RETURN HAS STRUGGLED HOWEVER...BOTH AT THE SURFACE AND IN
THE DEEP LAYER PER OBSERVATIONS AND PWAT ANALYSIS AND IS A REASON
SHOWER COVERAGE IS LIKELY TO BE MORE LIMITED THAN IT COULD BE
GIVEN THE UPPER FORCING AHEAD OF THIS WAVE...AND IT WILL TAKE SOME
TIME FOR THE VERY DRY LOWER ATMOSPHERE TO SATURATE. A NARROW
CORRIDOR OF 700-900 MB MOISTURE TRANSPORT ALONG A MID-LEVEL JET
HAS STILL HELPED TO INCREASE ECHOES UPSTREAM DURING THE FIRST HALF
OF THE AFTERNOON AND THIS WILL LIKELY BE JUST ENOUGH TO CONTINUE
DOING SUCH WITH STEEPENING MID-LEVEL LAPSE RATES IN CONCERT WITH
THE NARROW MOISTURE CONVERGENCE. MOST OF THE HIGH-RES CONVECTIVE
ALLOWING MODELS PREDICT AN INCREASE IN CONVECTIVE-TYPE ECHOES
ACROSS NORTH CENTRAL IL BETWEEN 23Z AND 03Z SHIFTING EASTWARD AND
FADING SLOWLY THROUGH EARLY OVERNIGHT AS THE FRONT SHIFTS EAST.
WITH SEVERAL OF THESE GUIDANCE MEMBERS INDICATING HIGHER
REFLECTIVITY AND A NARROW CORRIDOR OF 200-400 J/KG OF MUCAPE PER
THE RAP ALONG THE FRONT...WOULD EXPECT A FEW STORMS WITHIN THE
GENERAL SHOWERS. HAVE ADAPTED HOURLY POPS THROUGH THIS EVENING
PERIOD OF THE FORECAST. AS PREVIOUS FORECAST DID KEEP MOST OF
TONIGHTS TEMPERATURE DROP AFTER THE FRONTAL PASSAGE FROM WEST TO
EAST.
SUNDAY...HIGH PRESSURE STILL LOOKS TO BRIEFLY PREVAIL FOR THIS
PERIOD. THE MOST NOTEWORTHY ASPECT ABOUT THIS IS IT LOOKS TO LINE
UP DOWN THE AXIS OF LAKE MICHIGAN BY MIDDAY AND ALLOW FOR A FAIRLY
STOUT LAKE BREEZE. THIS WILL BE AIDED BY THE FACT THAT
TEMPERATURES SHOULD MODERATE NICELY ON SUNDAY OVER LAND DUE TO
ONLY A SMALL WINDOW OF COLD AIR ADVECTION BEHIND THE FRONT TONIGHT
AND A DRY AIR MASS AND PREDICTED SUNSHINE DURING SUNDAY. THE
TEMPERATURE AND PRESSURE DIFFERENCES WITHIN A LIGHT WIND FIELD
SHOULD DRIVE A STRONG LAKE BREEZE...AND THE AFTERNOON TEMPERATURE
DROP FOR DOWNTOWN CHICAGO AND OTHER NEAR LAKE AREAS MAY BE AS MUCH
AS 15 DEGREES.
SUNDAY NIGHT AND MONDAY...AN ACTIVE WEST-TO-EAST PACIFIC JET OVER
120 KT AS SEEN ON HEMISPHERIC WATER VAPOR TODAY WILL DIG ITS WAY
INTO THE WESTERN U.S. WITH TROUGH DEVELOPMENT AND UPSTREAM
SOUTHWEST FLOW OVER THE MIDWEST. A LEAD IMPULSE IN THIS FLOW IS
WELL PREDICTED ON GUIDANCE TO PASS OVER THE AREA DURING LATE
SUNDAY NIGHT INTO MONDAY MORNING. THIS LOOKS TO TIGHTEN AN UPPER
LEVEL WARM FRONT AND ALLOW FOR SATURATED ISENTROPIC LIFT FOR RAIN
SHOWERS. ELEVATED INSTABILITY DOES INCREASE AS THE WARM NOSE
BUILDS IN WITHIN THE LOWER LEVELS...AND START THUNDER IN THIS
FORECAST PERIOD ITS TOO TOUGH TO DISCERN A PERIOD WHERE THERE
WOULD NOT BE A THUNDER CHANCE ALL THE WAY THROUGH WEDNESDAY NIGHT.
IN THE WAKE OF THIS LEAD IMPULSE HEIGHTS LOOK TO BUILD ON MONDAY
AS THE PRIMARY TROUGH DEVELOPS. ITS A LITTLE INTERESTING AS THERE
SHOULD BE A SURFACE WARM FRONT...POSSIBLY DIABATICALLY
ENHANCED...LAID OUT SOMEWHERE IN THE CENTRAL IL TO NORTHERN IL
REGION. THE ONLY THING IS WITH SHORT WAVE RIDGING HINTED AT THIS
FEATURE APPEARS TO BE FAIRLY BENIGN...BUT SOMETHING TO KEEP AN
EYE ON.
MIDWEEK...AN ACTIVE PERIOD HERE AS PROLONGED SURFACE CYCLOGENESIS
BEGINS OVER THE SOUTHERN PLAINS MONDAY NIGHT AND CONTINUES THROUGH
TUESDAY WITH THE SURFACE WAVE ADVANCING ENE ON WED. MODEL
GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THIS...LATCHING MORE
ONTO AN EC SOUTHERN SOLUTION. HAVE CONTINUED TO LEAN THAT WAY WITH
THE FORECAST WHICH MEANS INHIBITING TEMPERATURES ON WHAT COULD BE
GIVEN 850MB TEMPERATURES CLIMBING TO 8C-12C...ESPECIALLY NORTH OF
I-80. WITH FLOW OFF THE LAKE TUESDAY AND WEDNESDAY DUE TO THE LOW
BEING SOUTHWEST OF THE AREA...TEMPERATURES NEAR THE LAKE WILL
REMAIN COOLER. ALSO THIS FORECAST PATTERN MEANS LIKELY SEVERAL
BOUTS OF PRECIP WITH THE PROXIMITY OF THE ELEVATED WARM/STATIONARY
FRONT. THE 06.12 GFS AND EC RUNS BOTH HAVE OVER TWO AND A HALF
INCHES OF RAIN FORECAST AREA WIDE FROM SUNDAY NIGHT THROUGH
THURSDAY. WHILE IT IS CHALLENGING TO FOCUS ANY WINDOW FOR
CATEGORICAL POPS...IT WOULD SEEM WEDNESDAY AND WEDNESDAY NIGHT
WOULD BE THE MOST FAVORED PERIODS FOR STRONGER DYNAMIC FORCING AND
POSSIBLY MORE ROBUST ELEVATED CONVECTION WITH THE LARGE SCALE
UPPER TROUGH MOVING EASTWARD. COOLING BEHIND THE FRONT LOOKS
SOMEWHAT STRONG AND THERE IS A POTENTIAL TO SEE SOME MIX IN THE
WAKE OF THE FRONT...BUT CONFIDENCE IS VERY LOW ON HOW THIS SYSTEM
WILL EVOLVE AS IT LIFTS OUT.
BEYOND...HAVE GONE PRIMARILY WITH A MODEL CONSENSUS AT THE END OF
NEXT WEEK AS THE UPPER FLOW PATTERN WORKS FROM BRIEFLY NORTHWEST
BACK TO WEST. TEMPERATURES SHOULD GRADUALLY MODERATE BUT
CONFIDENCE IS LOW ON PRECIP CHANCES AS THE PATTERN STILL LOOKS
DISTURBED.
MTF
&&
.FIRE WEATHER...
328 AM...EASTERLY FLOW HAS MAINTAINED MUCH DRIER AIR ACROSS THE
REGION AND EXPECT A SLOW RETURN OF LOW LEVEL MOISTURE ACROSS THE
AREA TODAY. IT APPEARS DEWPOINTS WILL INCREASE BACK INTO THE
40S...BUT PROBABLY NOT UNTIL LATE AFTERNOON ACROSS WESTERN IL AND
THE REST OF THE AREA THIS EVENING. THUS MINIMUM RH VALUES TODAY
WILL LIKELY BE IN THE 35-40 PERCENT RANGE AND COULD POSSIBLY DIP
INTO THE 30-35 PERCENT RANGE. WHILE THESE EXPECTED VALUES WILL
REMAIN ABOVE RED FLAG CRITERIA OF 25 PERCENT...SOUTHERLY WINDS ARE
EXPECTED TO QUICKLY INCREASE THIS MORNING WITH GUSTS AS HIGH AS 40
MPH FROM LATE MORNING THROUGH SUNSET WITH THE POTENTIAL FOR HIGHER
GUSTS. WHILE THERE COULD BE A FEW LIGHT SHOWERS OR SPRINKLES
TODAY...THE BEST TIMING FOR SHOWERS AND A FEW THUNDERSTORMS WILL
BE FROM LATE AFTERNOON THROUGH MID/LATE EVENING. TEN HOUR FUEL
MOISTURE DIPPED TO 8-9 PERCENT ON FRIDAY AND SIMILAR VALUES ARE
POSSIBLE TODAY. AS A RESULT...THERE WILL BE AN INCREASED FIRE
DANGER AND WHILE MEETING RED FLAG CRITERIA IS NOT EXPECTED...
CONDITIONS WILL NEED TO BE MONITORED THROUGH DAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS OVERNIGHT INTO SUNDAY MORNING
* WIND SHIFT TO EASTERLY SUNDAY AFTERNOON
IZZI
//DISCUSSION...UPDATED 06Z...
COLD FRONT MOVING THROUGH THE REGION AT THIS TIME WITH SHRA/TSRA
MOVING EAST OF THE REGION. EXPANDING BANK OF STRATUS HAS BEEN
NOTED ON SATELLITE IMAGERY UPSTREAM OVER WI/IA INTO NW IL WITH
GUIDANCE SUGGESTING THIS SHOULD CONTINUE TO EXPAND EAST INTO THE
TERMINALS OVERNIGHT. DOES APPEAR THAT MIXING/HEATING SHOULD HELP
ERODE THE STRATUS SUNDAY MORNING...THOUGH TIMING OF SCATTERING OUT
CIGS IS UNCERTAIN. WESTERLY WINDS SHOULD GUST OCCASIONALLY TO
15-20KT OVERNIGHT BEFORE EASING SUNDAY MORNING. PRESSURE FALLS
OVER THE PLAINS EXPECTED TO RESULT IN AN ABRUPT SHIFT TO EASTERLY
WINDS SUNDAY EVENING...WITH THE TIMING OF THAT WIND SHIFT LIKELY A
BIT EARLIER AT ORD/MDW/GYY AS COLLAPSING GRADIENT IN THE AFTERNOON
SHOULD ALLOW FOR ROBUST LAKE BREEZE DEVELOPMENT. NEXT DISTURBANCE
LIKELY TO APPROACH THE REGION TOWARD THE END OF OR JUST BEYOND
THE ORD 30 TAF HOUR PERIOD WITH ADDITIONAL SHRA/TSRA EXPECTED AT
THAT TIME.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN LOW END MVFR CIGS OVERNIGHT INTO SUN
AM
* LOW-MEDIUM CONFIDENCE ON TIMING OF IMPROVEMENT TO VFR SUNDAY
MORNING
* HIGH CONFIDENCE ON WIND SHIFT TO EAST SUN PM
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SHRA/TSRA LIKELY EARLY. MVFR/BRIEF IFR POSSIBLE EARLY.
TUESDAY THROUGH THURSDAY NIGHT...PERIODIC CHANCE FOR SHRA/TSRA.
PERIODIC MVFR CIGS/VSBY LIKELY WITH BRIEF IFR POSSIBLE.
FRIDAY...PROBABLE VFR.
MDB
&&
.MARINE...
241 PM CDT
LOW PRESSURE OVER SOUTHERN MINNESOTA THIS AFTERNOON IS LIFTING A
STRONG WARM FRONT ACROSS LAKE MICHIGAN TODAY. WINDS OVER THE LAND
ARE TOPPING OUT AROUND 35 KT THIS AFTERNOON WITH THESE GALES
EXTENDING INTO THE NEARSHORE WATERS WHERE A GALE WARNING REMAINS
IN EFFECT THROUGH THIS EVENING. HOWEVER...WITH TEMPERATURES
PUSHING 70 ACROSS NORTHERN ILLINOIS/INDIANA...VERY STABLE
CONDITIONS ARE SETTING UP OVER THE OPEN WATERS OF THE LAKE AND
SHOULD BE INHIBITING THE STRONGER GUSTS FROM REACHING THE LAKE
SURFACE. THE LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATE
THIS EVENING WITH A TRAILING COLD FRONT PUSHING ACROSS THE LAKE
SHORTLY THEREAFTER WITH WINDS TURNING WESTERLY AND DIMINISHING.
ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO MOVE INTO THE REGION
MIDWEEK...THOUGH MODELS CONTINUE TO STRUGGLE WITH TRACK AND TIMING
MAKING IT DIFFICULT TO PIN DOWN DETAILS REGARDING OVER THE LAKE.
CONTINUE TO FAVOR A FARTHER SOUTH SOLUTION SUPPORTED BY THE
CONSISTENT ECMWF...WHICH THE LATEST GFS HAS TRENDED TOWARDS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1154 PM CDT SAT APR 6 2013
.DISCUSSION...
ISSUED 900 PM CDT SAT APR 6 2013
A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
PROGRESS EASTWARD ACROSS THE NORTHERN HALF OF THE CWA THIS EVENING
AHEAD OF A COLD FRONT. THE WINDOW OF OPPORTUNITY FOR THUNDER LOOKS
TO BE AROUND 2 HOURS WITH THUNDER JUST REPORTED IN PIA AHEAD OF
THE STRONGER LINE BACK NEAR GALESBURG. THE LOW LEVEL CONVERGENCE
AND INSTABILITY LOOKS TO BE GRADUALLY WEAKENING AFTER SUNSET...AND
THE FRONTAL CIRCULATIONS ARE FORECAST TO NEARLY DISSIPATE BY 12Z
WHEN THE FRONT REACHES OUR SOUTHEAST COUNTIES. WE MAINLY KEPT THE
HIGH CHANCE POPS ACROSS THE NORTH...AND PROGRESSED THEM TOWARD
CHAMPAIGN BY 06Z/1AM WITH ONLY SLIGHT CHANCE POPS IN THE SOUTHEAST
THIRD OF OUR COUNTIES AFTER 06Z/1AM.
THE GUSTY WINDS ARE MAINLY CONFINED TO AREAS EAST OF LINCOLN TO
BLOOMINGTON AT 9 PM. LIGHTER WINDS WILL ARRIVE WITH THE COLD FRONT
AND A WIND SHIFT TO THE WEST.
THE FRONT IS STILL EXPECTED TO RETURN NORTH AND BECOME ACTIVE
AGAIN SUNDAY AFTERNOON AND ESPECIALLY SUNDAY NIGHT IN THE WEST.
FOR TONIGHT...UPDATED THE POP/WEATHER AND WINDS TO MORE CLOSELY
MATCH CURRENT TRENDS. NO MAJOR CHANCES OVERALL. UPDATED INFO WILL
BE AVAILABLE SHORTLY.
SHIMON
&&
.AVIATION...
ISSUED 1154 PM CDT SAT APR 6 2013...FOR THE 06Z TAFS
SOME SHOWERS MAY AFFECT CMI FOR THE FIRST HALF HOUR OF THE TAF
PERIOD...OTHERWISE THE TERMINAL SITES SHOULD REMAIN DRY OVER
THE NEXT 24 HOURS.
THE COLD FRONT WILL PASS ACROSS DEC/CMI OVER THE NEXT HOUR OR
TWO...SO WINDS SHOULD DIMINISH FROM STRONG SOUTH TO LIGHTER
SOUTHWEST AROUND 12-14KT. LATER TONIGHT ALL TAF SITES SHOULD SEE
WEST WINDS AROUND 10KT.
SOME MVFR CLOUDS ARE EXPECTED TO APPROACH OUR NORTHERN
COUNTIES...WITH PIA AND BMI POSSIBLY SEEING SOME OF THAT. LIGHT
FOG MAY EVEN AFFECT PIA AND BMI. I ADDED A TEMPO FOR BKN015 FOR
12Z TO 15Z TO MATCH THE HRRR OUTPUT FOR THAT TIME FRAME.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT SAT APR 6 2013
00Z MODELS CONTINUE A MILD AND UNSETTLED WEATHER PATTERN THROUGH
MID WEEK WITH COOLER AND DRIER CONDITIONS THE END OF NEXT WEEK.
WILL USE A MODEL BLEND THIS FORECAST PACKAGE. MET AND MAV GUIDANCE
TEMPS ARE SIMILAR THROUGH MON NIGHT AND STAYED FAIRLY CLOSE TO.
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
STRONG SOUTH WINDS OF 20-35 MPH AND GUSTS OF 35-50 MPH THIS
AFTERNOON WITH STRONGEST WIND GUSTS FROM I-72 NORTH. A SPECIAL
WEATHER STATEMENT WAS ISSUED TO ADDRESS THESE HIGH WINDS THROUGH
8 PM. 999 MB LOW PRESSURE OVER SOUTHCENTRAL MN HAS A COLD FRONT
INTO CENTRAL IA...NW MO AND CENTRAL OK. WARM FRONT HAD LIFTED NE
OF IL WITH MILD TEMPS IN THE UPPER 60S AND LOWER 70S OVER CENTRAL
AND SE IL AND MILDEST TEMPS SINCE NOV 10TH.
LOW PRESSURE TO MOVE TOWARD NORTHERN LAKE MI BY 06Z TONIGHT AND
PULL COLD FRONT TOWARD I-55. LOW PRESSURE DEEPENS TO 996 MB JUST
EAST OF UPPER MI BY 12Z/SUN AND COLD FRONT SWEEPS THROUGH SE IL
LATE TONIGHT INTO MID MORNING SUNDAY. HAVE CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS OVER CENTRAL IL THIS EVENING AND SHIFTING
INTO SE IL OVERNIGHT INTO MID MORNING SUNDAY. LIMITED MOISTURE
WITH COLD FRONT AND MODELS HAVE TRENDED LOWER WITH QPF AMOUNTS
TONIGHT INTO SUNDAY. LOWS TONIGHT RANGE FROM THE LOWER 40S NW OF
THE IL RIVER TO THE LOWER 50S IN SE IL.
FRONTAL BOUNDARY TO START LIFTING BACK NORTH TOWARD CENTRAL/SE IL
BY SUNSET SUNDAY AND RETURNING 20-40% CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS LATE SUNDAY AFTERNOON INTO PARTS OF CENTRAL
AND SW IL. HIGHS TO RANGE FROM THE MID 60S NORTH OF PEORIA TO THE
LOWER 70S SOUTH OF I-72. WARM FRONT LIFTS NORTH THROUGH CENTRAL IL
SUNDAY NIGHT AND INTO NORTHERN IL MON AND LIKELY ACCOMPANIED BY A
SHOWERS AND A CHANCE OF THUNDERSTORMS ESPECIALLY NORTH OF I-70.
MILD HIGHS MON AGAIN IN THE UPPER 60S AND LOWER 70S WITH COOLEST
READINGS FROM I-74 NORTH.
CHANCES OF SHOWERS AND THUNDERSTORMS LINGERS TUE AND HIGHEST POPS
IN NORTHERN AREAS CLOSER TO FRONTAL BOUNDARY LINGERING OVER
NORTHERN IL.
LONG TERM...WEDNESDAY THROUGH SATURDAY
STRONG LOW PRESSURE TO EJECT NE AROUND WED WITH BEST CHANCES OF
SHOWERS AND THUNDERSTORMS AND SPC HAS RISK OF STRONG TO SEVERE
STORMS OVER SOUTHERN IL WED. GFS IS QUICKER WITH THIS STORM SYSTEM
THAN THE ECMWF MODEL AND USED A BLEND FOR NOW WITH PLENTY OF TIME TO
SORT OUT THE TIMING DIFFERENCES. MAY BE A GRADIENT OF TEMPS WED WITH
COOLER HIGHS IN THE UPPER 50S NW OF THE IL RIVER AND MILDER LOWER
70S SE OF I-70. STRONG UPPER LEVEL TROF OVER THE MIDWEST THU TO KEEP
LOW CLOUDS AROUND ALONG WITH LINGERING CHANCES OF SHOWERS AND COOLER
TEMPS. DRIER WEATHER EXPECTED FRIDAY ALONG WITH TEMPS BEING A BIT
COOLER THAN NORMAL THU/FRI WITH HIGHS IN THE 50S.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1055 PM CDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 322 PM CDT MON APR 8 2013
THE MAIN FORECAST CONCERNS ARE THE SEVERE WEATHER CHANCES TONIGHT
AND TOMORROW AND WINTRY PRECIPITATION BEHIND THE COLD FRONT TUESDAY
NIGHT/WEDNESDAY.
A LARGE POTENT UPPER TROUGH IS DIGGING INTO THE INTERIOR MOUNTAIN
WEST THIS AFTERNOON WITH A WEAK WAVE MOVING NORTHEAST OVER THE GREAT
LAKES. THE DEEP TROUGH WILL BE THE WEATHER MAKER FOR THE NEXT FEW
DAYS. MOSTLY CLOUDY SKIES COVER MUCH OF KANSAS EXCEPT EXTREME
WESTERN AND SOUTHWESTERN SECTIONS. TEMPERATURES ARE WARM...IN THE
LOW 70S AND WINDS ARE BREEZY BETWEEN 10 AND 20 MPH.
&&
.UPDATE...
ISSUED AT 1055 PM CDT MON APR 8 2013
REST OF TONIGHT:
NUMEROUS STG-SVR TSRA CONTINUE TO SPREAD SLOWLY E OVER WRN & CNTRL
NEBRASKA LATE THIS EVENING WHERE STRONG(!) LWR-DECK MOISTURE
CONVERGENCE HAS PERSISTED THROUGHOUT THE EVENING. INTENSE MID-UPR
CYCLONE SPINNING OVER UT SHOULD DRIFT E OVER CO ROCKIES WHICH WITH
TIME WILL GRADUALLY INCREASE UPR-DECK DIFFLUENCE OVER NW KS & MOST
OOF NEBRASKA. SUCH SLOW EWD MOVEMENT OF THE MID-UPR CYCLONE WOULD
KEEP THE STRONG SW-NE ORIENTED STATIONARY FRONT WELL TO THE NW & N
OF KICT COUNTRY THE REST OF THE NGT. AS SUCH HAVE SLIGHTLY LOWERED
POPS OVER CNTRL KS EVEN FURTHER.
UPDATE ISSUED AT 654 PM CDT MON APR 8 2013
THIS EVENING:
WITH ALL TSRA OCCURRING WELL TO THE NW OF KICT COUNTRY EARLY THIS
EVENING (MORE SPECIFICALLY EXTREME NW KS & WRN NEBRASKA INCLUDING
THE PANHANDLE) HAVE REMOVED TSRA FROM SC & SE KS & LOWERED CNTRL
KS POPS TO ~20% & LIMITED MENTION TO AREAS GENERALLY NW OF A LINE
FROM GREAT BEND-LINCOLN. STILL ANTICIPATE TSRA OCCURRING OVER THE
AFORE-MENTIONED AREAS TO SPREAD E ALONG & N OF W-E ORIENTED WARM
FRONT THAT`LL GET BETTER DEFINED LATER TONIGHT. TSRA TRENDS WILL BE
WATCHED THE CLOSEST OF ALL PARAMETERS THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
THIS PERIOD IS THE ONE TO WATCH IN TERMS OF SEVERE WEATHER CHANCES.
THE POTENT UPPER LEVEL DISTURBANCE IS SLOWLY MAKING ITS WAY EASTWARD
WITH WEAK DIFFLUENCE OVER THE CENTRAL PLAINS. SOUTHERN KANSAS IS IN
THE WARM SECTOR AND LOW LEVEL INHIBITION (CIN) IS HIGH. THE RUC AND
NAM DO SHOW AN AREA OVER EXTREME NORTH CENTRAL OKLAHOMA WHERE CIN
DECREASES LATE THIS AFTERNOON/EARLY EVENING WHERE A THUNDERSTORM
COULD DEVELOP. CONFIDENCE IS NOT OVERLY HIGH THAT MUCH OF SOUTH
CENTRAL KANSAS WILL SEE A STORM...BUT AREAS WEST OF HIGHWAY 14 COULD
SEE A THUNDERSTORM BEFORE DARK THIS EVENING.
BEYOND THIS TONIGHT...THE MAIN FOCUS WILL BE OVER THE HIGH
PLAINS AND CENTRAL KANSAS NORTH OF I-70 WHERE CIN WILL BE ABLE TO
ERODE QUICKER BEFORE THE NOCTURNAL BOUNDARY LAYER TAKES HOLD. THESE
STORMS HAVE THE CHANCE OF BEING SEVERE WITH MODEST 1000-1500 J/KG
CAPE AND 40-55 KTS 0-6KM BULK SHEAR. THIS AREA WILL TRANSLATE
EASTWARD AND MOVE INTO CENTRAL KANSAS. THE BEST CHANCES FOR
PRECIPITATION OVERNIGHT WILL BE ALONG AND NORTH OF I-70.
THINGS CHANGE TUESDAY WITH THE VERY STRONG COLD FRONT BEGINNING TO
GAIN ITS MOMENTUM TUESDAY MORNING AS THE UPPER TROUGH MOVES INTO THE
AREA. THE POTENT FRONT WILL APPROACH CENTRAL KANSAS BY AFTERNOON.
AS THE FRONT REACHES CENTRAL AND EASTERN KANSAS...IT WILL BE ABLE TO
TAP MOIST BOUNDARY LAYER AIR...AND THE CAP WILL ERODE ALONG AND
NEAR THE FRONT IN THE AFTERNOON HOURS. A FEW DISCRETE STORMS MAY BE
ABLE TO DEVELOP EARLY...BUT WITH THE LARGE AMOUNT OF LINEAR FORCING
WITH THE FRONT A SQUALL LINE IS EXPECTED TO BECOME THE MAIN
CONVECTIVE MODE. THE STORMS ARE EXPECTED TO FIRE NEAR THE
I-135/I-35 CORRIDOR AND MOVE EASTWARD FROM THERE DURING THE EVENING
AND OVERNIGHT HOURS. THE MAIN THREATS ARE LARGE HAIL AND DAMAGING
WINDS WITH THE LINEAR CONVECTIVE MODE...BUT CANNOT RULE OUT A
TORNADO EARLY.
OUTSIDE OF THE SEVERE THUNDERSTORM CHANCES...THE OTHER MAIN CONCERN
IS TEMPERATURES BEHIND THE FRONT. THIS FRONT IS BEING FORCED SOUTH
BY COLD ARCTIC AIR. THIS WILL CAUSE TEMPERATURES TO DROP
DRASTICALLY ONCE THE FRONT MOVES THROUGH. USED THE NAM...FEELING IT
HAS THE BEST RESOLUTION AS A NON-DIURNAL TREND OVERNIGHT TONIGHT
THROUGH TOMORROW NIGHT.
BILLINGS
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
TUESDAY NIGHT - WEDNESDAY:
COLD TEMPERATURES BEHIND THE FRONT WILL BRING A SHOCK TO OUR
SYSTEMS...AS PRECIPITATION ON THE BACK SIDE OF THE UPPER LOW COULD
FALL AS A WINTRY MIX TUESDAY NIGHT AND EARLY WEDNESDAY IN CENTRAL
KANSAS. CONFIDENCE IN PRECIP TYPE IS LOW GIVEN LOW LEVEL PROFILES.
WILL ALLOW NEXT COUPLE SHIFTS TO FINE TUNE THESE CHANCES. BY
WEDNESDAY DAYTIME HIGH TEMPERATURES WILL BE WELL BELOW NORMAL...IN
THE UPPER 30S AND LOW 40S.
THURSDAY - SATURDAY:
BY THURSDAY THINGS DRY OUT WITH THE UPPER WAVE MAKING ITS WAY OVER
THE PLAINS...WITH SUBSIDENCE AND SURFACE HIGH PRESSURE BUILDING IN
BEHIND THE FRONT. THE ARCTIC AIR WILL HOLD ON AND TEMPS WILL
STRUGGLE TO WARM INTO THE 50S ON THURSDAY AND FRIDAY. BY SATURDAY
HIGH PRESSURE WILL MOVE SOUTHEAST AND SOUTHERLY FLOW WILL RETURN
HELPING TEMPERATURES TO IMPROVE BACK TO NEAR NORMAL IN THE LOW 60S.
SUNDAY - MONDAY:
ANOTHER WAVE WILL IMPACT THE REGION LATE IN THE WEEKEND AND EARLY
NEXT WEEK...BUT THE GUIDANCE IS OUT OF PHASE WITH THE SOLUTIONS.
THE GFS IS PULLING A FRONT THROUGH MUCH QUICKER THAN THE ECMWF.
CONFIDENCE ON THIS FEATURE IS LOW AND WENT WITH MODEL CONSENSUS.
BILLINGS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1055 PM CDT MON APR 8 2013
WITH TSRA EXPECTED TO REMAIN WELL TO THE NW & N THE KICT AVIATION
JURISDICTION THE REST OF THE NGT THE SOLE FOCUS IS ON CIGS. WITH
GRADUALLY "DRIER" AIR IN LOWEST ~3,000FT OF AIRMASS ADVECTING NW
ACROSS ERN & CNTRL KS OPTIMISM IS SLOWLY INCREASING THAT ALL 5
TERMINALS WILL MAINTAIN VFR STATUS FOR THE REMAINDER OF THE NIGHT
AND WELL INTO TUE MORNING. THEREFORE NOW ANTICIPATE 4,000-5,000FT
CIGS TO PREVAIL OVER ALL AREAS THRU ~18Z. AFTER 18Z STG-SVR TSRA
TO ERUPT AS STRONG COLD FRONT BEGINS TO PUSH SE TOWARD CNTRL KS.
SINCE THE COLD FRONT IS NOT EXPECTED TO ARRIVE CNTRL KS TIL LATE
TUE AFTERNOON & SC & SE KS TIL TUE EVENING/NGT...WILL NOT PROVIDE
SPECIFICS ON TSRA TIMING & INTENSITY AT THIS TIME.
&&
.FIRE WEATHER...
ISSUED AT 322 PM CDT MON APR 8 2013
FIRE WEATHER CONCERNS ARE LOW DURING THE NEXT COUPLE OF DAYS ARE
LOW...BUT BY WEDNESDAY STRONG WINDS BEHIND THE COLD FRONT WILL CAUSE
GRASSLAND FIRE DANGER TO BE VERY HIGH ACROSS MUCH OF CENTRAL AND
SOUTH CENTRAL KANSAS.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 64 72 34 43 / 10 60 60 40
HUTCHINSON 63 72 29 41 / 10 60 40 30
NEWTON 63 69 30 39 / 10 60 60 40
ELDORADO 63 73 35 43 / 10 60 60 40
WINFIELD-KWLD 64 74 36 44 / 10 60 60 40
RUSSELL 60 65 22 38 / 30 50 40 10
GREAT BEND 61 67 24 39 / 20 50 40 10
SALINA 63 70 31 41 / 20 60 50 30
MCPHERSON 63 69 30 40 / 20 60 50 30
COFFEYVILLE 64 75 45 46 / 10 40 70 50
CHANUTE 63 73 44 45 / 10 50 70 50
IOLA 63 73 44 45 / 10 50 70 50
PARSONS-KPPF 64 75 44 45 / 10 50 70 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1008 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1008 PM CDT MON APR 8 2013
MOST OF THE PRECIPITATION THIS EVENING HAS BEEN FOCUSED ACROSS FAR
NORTHWEST KANSAS AND SOUTHWEST AND CENTRAL NEBRASKA WHERE A FRONT
STRETCHES OVER THE AREA. LATEST TOP SOUNDING CONTINUED TO SHOW A
DECENT CAPPING INVERSION IN PLACE NEAR 700 MB...WITH MODEL SOUNDINGS
SHOWING LITTLE CHANGE THROUGH THE OVERNIGHT PERIOD. AS A
RESULT...HAVE CONTINUED TO TREND DOWN POPS ACROSS MUCH OF THE
CWA...ESPECIALLY OVER EAST CENTRAL KANSAS. WITH THE LLJ INCREASING
OVER NORTH CENTRAL AND NORTHEAST KANSAS TONIGHT...STILL CANNOT RULE
OUT SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING THIS
EVENING NEAR THE NEBRASKA/KANSAS BORDER...SO HAVE KEPT CHANCE POPS
IN FOR THAT AREA THROUGH THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
19Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW DIGGING SOUTHEAST INTO
SOUTHERN NV AND AZ. AT THE SURFACE A WEAK BOUNDARY NOTED MORE IN THE
DEWPOINT FIELD HAS LIFTED INTO SOUTHERN NEB.
TONIGHT WITH THE UPPER LOW ACROSS THE SOUTHWEST...THE FORECAST AREA
SHOULD REMAIN MAINLY UNDER SHORTWAVE RIDGING ALOFT WITH SOUTHERLY
RETURN FLOW PERSISTING. THIS LOW LEVEL FLOW IS EXPECTED TO ADVECT AN
ELEVATED MIXED LAYER OR CAPPING INVERSION NORTH INTO NEB AND THE
LATEST RAP SOUNDINGS SUPPORT THIS IDEA WITH A STRENGTHENING
INVERSION EARLY THIS EVENING ALONG THE NEB STATE LINE. SO AM
THINKING THAT ELEVATED STORMS ARE MORE LIKELY TO OCCUR OVER SOUTHERN
NEB WHERE ISENTROPIC UPGLIDE INTERACTS WITH THE WEAK BOUNDARY. SOME
OF THE LATEST HI RES MODELS ARE SHOWING A SIMILAR IDEA. STORMS THAT
FORM IN NORTH KS MAY STILL HAVE THE POTENTIAL FOR LARGE HAIL GIVEN
STEEP MID LEVEL LAPSE RATES. WITH CONTINUED SOUTHERLY FLOW AND
MOISTURE ADVECTION INTO THE AREA...A STRATUS DECK IS EXPECTED TO
REDEVELOP THIS EVENING. THE CLOUD COVER COMBINED WITH A WARM MOIST
BOUNDARY LAYER SHOULD CREATE A VERY MILD NIGHT WITH LOWS ONLY IN THE
LOWER 60S.
BY TUESDAY...THE MODELS HAVE TRENDED A LITTLE SLOWER WITH THE
FRONTAL PASSAGE AND ONLY BEGIN TO BRING IT INTO THE NORTH CENTRAL
COUNTIES BY LATE AFTERNOON. WITH THE SUBSTANTIAL CAPPING INVERSION
IN THE WARM SECTOR...THINK THAT DEEP MOIST CONVECTION WILL LIKELY
HOLD OFF UNTIL THE FRONT MOVES THROUGH TO LIFT SURFACE PARCELS TO
THE LFC. WITH THE LINEAR FORCING FOR CONVECTION...THUNDERSTORMS MAY
QUICKLY DEVELOP INTO A SQUALL LINE WITH STRONG WINDS AND HAIL THE
MOST LIKELY HAZARD. SO THE FORECAST SHOWS POPS INCREASING LATE IN
THE AFTERNOON ACROSS NORTH CENTRAL KS. SINCE THERE IS NO REAL COLD
AIR ADVECTION TO SPEAK OF THROUGH THE DAY...HIGHS SHOULD AGAIN BE
MILD WITH UPPER 60S TO 70S FROM NORTH CENTRAL KS TO EAST CENTRAL KS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
FOR THE MOST PART THE MAIN SQUALL LINE APPEARS POISED TO MOVE
ACROSS THE FORECAST AREA BETWEEN 00Z AND 06Z DURING THE EVENING
HOURS ON TUESDAY. WARM NOSE AROUND 775MB WILL INHIBIT CONVECTION
IN THE WARM SECTOR AND THINK MOST LOCATIONS WILL NOT SEE ACTIVITY
UNTIL THE FORCING WITH THE FRONT BREAKS THROUGH. MAY HAVE ONGOING
CONVECTION ALONG AND NORTH OF THE WARM FRONT ACROSS NORTHERN
KANSAS AT THE BEGINNING OF THE PERIOD AS WELL. 0-6KM WIND SHEAR
VECTORS GENERALLY 50-60KTS BUT DIRECTIONAL TURNING IS NOT AS
IMPRESSIVE. GIVEN INSTABILITY GENERALLY 800-1200J/KG THINK THAT
MAIN CONCERN WILL BE WINDS WITH THE STORMS AS THE LINE PASSES.
SOME LOCALLY HEAVY RAIN ALSO POSSIBLE AND CANNOT RULE OUT ISOLATED
TORNADOES ALONG THE LINE...BUT AT THIS TIME IS NOT THE PRIMARY
CONCERN. TRAILING RAIN AND ISOLATED T CONTINUE THROUGH THE NIGHT.
NEXT CONCERN IS COLD AIR DIVING SOUTHWARD BEHIND THIS SYSTEM. WARM
NOSE IS INITIALLY SO WARM THINK THAT PRECIP WILL STAY AS RAIN
DESPITE COOLING SURFACE TEMPERATURES...BUT AS THIS NOSE COOLS
THEN MORE COMPLEX PRECIP TYPES COME INTO PLAY. BY THE TIME IT GETS
COLD ENOUGH ALOFT FOR SNOW...THE MOISTURE AND LIFT ARE GENERALLY
EAST OF THE AREA. AS THE COLD AIR AT THE SURFACE GETS COLDER...THE
CHANCE FOR A CHANGEOVER TO SLEET OR FREEZING RAIN ALSO INCREASES.
HAVE STARTED WITH A RAIN SNOW MIX ACROSS THE NORTHWEST...BUT THINK
THIS WILL BE MORE OF A MIXED BAG...WITH LITTLE OF IT STICKING TO
THE GROUND AND ANY ACCUMULATION ON ELEVATED SURFACES. INITIAL
CHANCES FOR MIXED PRECIP ARE NORTH AND WEST OF MANHATTAN AFTER
MIDNIGHT INTO WEDNESDAY MORNING...RETREATING SOMEWHAT BACK INTO
NORTH CENTRAL KANSAS WEDNESDAY AFTERNOON. THE CHANCES THEN SPREAD
EASTWARD WITH A MIX POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING
ACROSS MUCH OF NORTHEAST AND EAST CENTRAL KANSAS. WILL HAVE TO
MONITOR FORECAST SOUNDINGS OVER NEXT FEW RUNS...BUT A QUICK ROUND
OF SOME TYPE OF FREEZING PRECIP LOOKS POSSIBLE FOR NORTH CENTRAL
KANSAS.
THE AIRMASS THAT DROPS INTO THE PLAINS BEHIND THE FRONT HOLDS
HIGHS IN THE 30S AND 40S WEDNESDAY...40S FOR THURSDAY...SLOWLY
RISING TOWARD 50 ON FRIDAY AND BACK TOWARD NORMAL LATER IN THE
WEEKEND. OVERNIGHT LOW TEMPERATURES MAY FALL BELOW FREEZING
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...FINALLY RISING BACK INTO
THE 40S SATURDAY NIGHT. ALTHOUGH THE GROWING SEASON IS SLOW TO
START...ITS WORTH NOTING THAT EARLY EMERGENT VEGETATION WILL SEE
COLD OVERNIGHT LOWS MID TO LATE WEEK. 67
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 631 PM CDT MON APR 8 2013
FOR 00Z TAFS...BORDERLINE VFR/MVFR CONDITIONS EXPECTED EARLY THIS
EVENING. HOWEVER...THE STEADY SOUTHERLY FLOW WILL ADVECT MORE
MOISTURE INTO THE REGION THIS EVENING AND OVERNIGHT...RESULTING IN
WIDESPREAD MVFR CIGS AND POSSIBLY A PERIOD OF IFR CIGS THROUGH
SUNRISE. WHILE THERE IS A CHANCE FOR A FEW SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP IN THE AREA TONIGHT AND OVERNIGHT...CONFIDENCE IN
TIMING AND LOCATION IS TOO LOW AT THIS TIME TO WARRANT INCLUDING IN
THE TAF. MVFR CONDITIONS EXPECTED THROUGH THE DAY ON TUESDAY AHEAD
OF A COLD FRONT THAT WILL PASS THROUGH THE TAF SITES TUESDAY
EVENING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
720 PM CDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 322 PM CDT MON APR 8 2013
THE MAIN FORECAST CONCERNS ARE THE SEVERE WEATHER CHANCES TONIGHT
AND TOMORROW AND WINTRY PRECIPITATION BEHIND THE COLD FRONT TUESDAY
NIGHT/WEDNESDAY.
A LARGE POTENT UPPER TROUGH IS DIGGING INTO THE INTERIOR MOUNTAIN
WEST THIS AFTERNOON WITH A WEAK WAVE MOVING NORTHEAST OVER THE GREAT
LAKES. THE DEEP TROUGH WILL BE THE WEATHER MAKER FOR THE NEXT FEW
DAYS. MOSTLY CLOUDY SKIES COVER MUCH OF KANSAS EXCEPT EXTREME
WESTERN AND SOUTHWESTERN SECTIONS. TEMPERATURES ARE WARM...IN THE
LOW 70S AND WINDS ARE BREEZY BETWEEN 10 AND 20 MPH.
&&
.UPDATE...
ISSUED AT 654 PM CDT MON APR 8 2013
THIS EVENING:
WITH ALL TSRA OCCURRING WELL TO THE NW OF KICT COUNTRY EARLY THIS
EVENING (MORE SPECIFICALLY EXTREME NW KS & WRN NEBRASKA INCLUDING
THE PANHANDLE) HAVE REMOVED TSRA FROM SC & SE KS & LOWERED CNTRL
KS POPS TO ~20% & LIMITED MENTION TO AREAS GENERALLY NW OF A LINE
FROM GREAT BEND-LINCOLN. STILL ANTICIPATE TSRA OCCURRING OVER THE
AFORE-MENTIONED AREAS TO SPREAD E ALONG & N OF W-E ORIENTED WARM
FRONT THAT`LL GET BETTER DEFINED LATER TONIGHT. TSRA TRENDS WILL BE
WATCHED THE CLOSEST OF ALL PARAMETERS THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
THIS PERIOD IS THE ONE TO WATCH IN TERMS OF SEVERE WEATHER CHANCES.
THE POTENT UPPER LEVEL DISTURBANCE IS SLOWLY MAKING ITS WAY EASTWARD
WITH WEAK DIFFLUENCE OVER THE CENTRAL PLAINS. SOUTHERN KANSAS IS IN
THE WARM SECTOR AND LOW LEVEL INHIBITION (CIN) IS HIGH. THE RUC AND
NAM DO SHOW AN AREA OVER EXTREME NORTH CENTRAL OKLAHOMA WHERE CIN
DECREASES LATE THIS AFTERNOON/EARLY EVENING WHERE A THUNDERSTORM
COULD DEVELOP. CONFIDENCE IS NOT OVERLY HIGH THAT MUCH OF SOUTH
CENTRAL KANSAS WILL SEE A STORM...BUT AREAS WEST OF HIGHWAY 14 COULD
SEE A THUNDERSTORM BEFORE DARK THIS EVENING.
BEYOND THIS TONIGHT...THE MAIN FOCUS WILL BE OVER THE HIGH
PLAINS AND CENTRAL KANSAS NORTH OF I-70 WHERE CIN WILL BE ABLE TO
ERODE QUICKER BEFORE THE NOCTURNAL BOUNDARY LAYER TAKES HOLD. THESE
STORMS HAVE THE CHANCE OF BEING SEVERE WITH MODEST 1000-1500 J/KG
CAPE AND 40-55 KTS 0-6KM BULK SHEAR. THIS AREA WILL TRANSLATE
EASTWARD AND MOVE INTO CENTRAL KANSAS. THE BEST CHANCES FOR
PRECIPITATION OVERNIGHT WILL BE ALONG AND NORTH OF I-70.
THINGS CHANGE TUESDAY WITH THE VERY STRONG COLD FRONT BEGINNING TO
GAIN ITS MOMENTUM TUESDAY MORNING AS THE UPPER TROUGH MOVES INTO THE
AREA. THE POTENT FRONT WILL APPROACH CENTRAL KANSAS BY AFTERNOON.
AS THE FRONT REACHES CENTRAL AND EASTERN KANSAS...IT WILL BE ABLE TO
TAP MOIST BOUNDARY LAYER AIR...AND THE CAP WILL ERODE ALONG AND
NEAR THE FRONT IN THE AFTERNOON HOURS. A FEW DISCRETE STORMS MAY BE
ABLE TO DEVELOP EARLY...BUT WITH THE LARGE AMOUNT OF LINEAR FORCING
WITH THE FRONT A SQUALL LINE IS EXPECTED TO BECOME THE MAIN
CONVECTIVE MODE. THE STORMS ARE EXPECTED TO FIRE NEAR THE
I-135/I-35 CORRIDOR AND MOVE EASTWARD FROM THERE DURING THE EVENING
AND OVERNIGHT HOURS. THE MAIN THREATS ARE LARGE HAIL AND DAMAGING
WINDS WITH THE LINEAR CONVECTIVE MODE...BUT CANNOT RULE OUT A
TORNADO EARLY.
OUTSIDE OF THE SEVERE THUNDERSTORM CHANCES...THE OTHER MAIN CONCERN
IS TEMPERATURES BEHIND THE FRONT. THIS FRONT IS BEING FORCED SOUTH
BY COLD ARCTIC AIR. THIS WILL CAUSE TEMPERATURES TO DROP
DRASTICALLY ONCE THE FRONT MOVES THROUGH. USED THE NAM...FEELING IT
HAS THE BEST RESOLUTION AS A NON-DIURNAL TREND OVERNIGHT TONIGHT
THROUGH TOMORROW NIGHT.
BILLINGS
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
TUESDAY NIGHT - WEDNESDAY:
COLD TEMPERATURES BEHIND THE FRONT WILL BRING A SHOCK TO OUR
SYSTEMS...AS PRECIPITATION ON THE BACK SIDE OF THE UPPER LOW COULD
FALL AS A WINTRY MIX TUESDAY NIGHT AND EARLY WEDNESDAY IN CENTRAL
KANSAS. CONFIDENCE IN PRECIP TYPE IS LOW GIVEN LOW LEVEL PROFILES.
WILL ALLOW NEXT COUPLE SHIFTS TO FINE TUNE THESE CHANCES. BY
WEDNESDAY DAYTIME HIGH TEMPERATURES WILL BE WELL BELOW NORMAL...IN
THE UPPER 30S AND LOW 40S.
THURSDAY - SATURDAY:
BY THURSDAY THINGS DRY OUT WITH THE UPPER WAVE MAKING ITS WAY OVER
THE PLAINS...WITH SUBSIDENCE AND SURFACE HIGH PRESSURE BUILDING IN
BEHIND THE FRONT. THE ARCTIC AIR WILL HOLD ON AND TEMPS WILL
STRUGGLE TO WARM INTO THE 50S ON THURSDAY AND FRIDAY. BY SATURDAY
HIGH PRESSURE WILL MOVE SOUTHEAST AND SOUTHERLY FLOW WILL RETURN
HELPING TEMPERATURES TO IMPROVE BACK TO NEAR NORMAL IN THE LOW 60S.
SUNDAY - MONDAY:
ANOTHER WAVE WILL IMPACT THE REGION LATE IN THE WEEKEND AND EARLY
NEXT WEEK...BUT THE GUIDANCE IS OUT OF PHASE WITH THE SOLUTIONS.
THE GFS IS PULLING A FRONT THROUGH MUCH QUICKER THAN THE ECMWF.
CONFIDENCE ON THIS FEATURE IS LOW AND WENT WITH MODEL CONSENSUS.
BILLINGS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 654 PM CDT MON APR 8 2013
AT ISSUANCE CIGS OVER MOST AREAS WERE VFR...THE EXCEPTIONS BEING IN
SC KS WHERE A FEW AREAS HAD DROPPED BACK INTO MVFR STATUS. CIGS TO
LOWER OVER ALL AREAS AS EVENING PROGRESSES...AS RICHER LOWER-DECK
MOISTURE SURGES N/NW ACROSS KS WITH ALL 5 TERMINALS IN MVFR STATUS
BY 05Z THEN INTO IFR BY 08Z. DO NOT ANTICIPATE SIGNIFICANT VSBY
RESTRICTIONS AS BOUNDARY LAYER SHOULD BE SUFFICIENTLY MIXED. TSRA
OCCURRING OVER EXTREME NW KS & WRN NEBRASKA (INCLUDING PANHANDLE)
TO SPREAD E LATE TONIGHT WITH BULK OF ACTIVITY OCCURRING N OF KRSL
& KSLN. S/SE WINDS SUSTAINED ~17-22KTS/20-25MPH MAY OCCASIONALLY
GUST TO NEAR 30KTS THROUGHOUT THE NIGHT & TUE MORNING.
&&
.FIRE WEATHER...
ISSUED AT 322 PM CDT MON APR 8 2013
FIRE WEATHER CONCERNS ARE LOW DURING THE NEXT COUPLE OF DAYS ARE
LOW...BUT BY WEDNESDAY STRONG WINDS BEHIND THE COLD FRONT WILL CAUSE
GRASSLAND FIRE DANGER TO BE VERY HIGH ACROSS MUCH OF CENTRAL AND
SOUTH CENTRAL KANSAS.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 64 72 34 43 / 10 60 60 40
HUTCHINSON 63 72 29 41 / 20 60 40 30
NEWTON 63 69 30 39 / 20 60 60 40
ELDORADO 63 73 35 43 / 10 60 60 40
WINFIELD-KWLD 64 74 36 44 / 10 60 60 40
RUSSELL 60 65 22 38 / 40 50 40 10
GREAT BEND 61 67 24 39 / 30 50 40 10
SALINA 63 70 31 41 / 30 60 50 30
MCPHERSON 63 69 30 40 / 20 60 50 30
COFFEYVILLE 64 75 45 46 / 10 40 70 50
CHANUTE 63 73 44 45 / 10 50 70 50
IOLA 63 73 44 45 / 10 50 70 50
PARSONS-KPPF 64 75 44 45 / 10 50 70 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS TOPEKA KS
632 PM CDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
19Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW DIGGING SOUTHEAST INTO
SOUTHERN NV AND AZ. AT THE SURFACE A WEAK BOUNDARY NOTED MORE IN THE
DEWPOINT FIELD HAS LIFTED INTO SOUTHERN NEB.
TONIGHT WITH THE UPPER LOW ACROSS THE SOUTHWEST...THE FORECAST AREA
SHOULD REMAIN MAINLY UNDER SHORTWAVE RIDGING ALOFT WITH SOUTHERLY
RETURN FLOW PERSISTING. THIS LOW LEVEL FLOW IS EXPECTED TO ADVECT AN
ELEVATED MIXED LAYER OR CAPPING INVERSION NORTH INTO NEB AND THE
LATEST RAP SOUNDINGS SUPPORT THIS IDEA WITH A STRENGTHENING
INVERSION EARLY THIS EVENING ALONG THE NEB STATE LINE. SO AM
THINKING THAT ELEVATED STORMS ARE MORE LIKELY TO OCCUR OVER SOUTHERN
NEB WHERE ISENTROPIC UPGLIDE INTERACTS WITH THE WEAK BOUNDARY. SOME
OF THE LATEST HI RES MODELS ARE SHOWING A SIMILAR IDEA. STORMS THAT
FORM IN NORTH KS MAY STILL HAVE THE POTENTIAL FOR LARGE HAIL GIVEN
STEEP MID LEVEL LAPSE RATES. WITH CONTINUED SOUTHERLY FLOW AND
MOISTURE ADVECTION INTO THE AREA...A STRATUS DECK IS EXPECTED TO
REDEVELOP THIS EVENING. THE CLOUD COVER COMBINED WITH A WARM MOIST
BOUNDARY LAYER SHOULD CREATE A VERY MILD NIGHT WITH LOWS ONLY IN THE
LOWER 60S.
BY TUESDAY...THE MODELS HAVE TRENDED A LITTLE SLOWER WITH THE
FRONTAL PASSAGE AND ONLY BEGIN TO BRING IT INTO THE NORTH CENTRAL
COUNTIES BY LATE AFTERNOON. WITH THE SUBSTANTIAL CAPPING INVERSION
IN THE WARM SECTOR...THINK THAT DEEP MOIST CONVECTION WILL LIKELY
HOLD OFF UNTIL THE FRONT MOVES THROUGH TO LIFT SURFACE PARCELS TO
THE LFC. WITH THE LINEAR FORCING FOR CONVECTION...THUNDERSTORMS MAY
QUICKLY DEVELOP INTO A SQUALL LINE WITH STRONG WINDS AND HAIL THE
MOST LIKELY HAZARD. SO THE FORECAST SHOWS POPS INCREASING LATE IN
THE AFTERNOON ACROSS NORTH CENTRAL KS. SINCE THERE IS NO REAL COLD
AIR ADVECTION TO SPEAK OF THROUGH THE DAY...HIGHS SHOULD AGAIN BE
MILD WITH UPPER 60S TO 70S FROM NORTH CENTRAL KS TO EAST CENTRAL KS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
FOR THE MOST PART THE MAIN SQUALL LINE APPEARS POISED TO MOVE
ACROSS THE FORECAST AREA BETWEEN 00Z AND 06Z DURING THE EVENING
HOURS ON TUESDAY. WARM NOSE AROUND 775MB WILL INHIBIT CONVECTION
IN THE WARM SECTOR AND THINK MOST LOCATIONS WILL NOT SEE ACTIVITY
UNTIL THE FORCING WITH THE FRONT BREAKS THROUGH. MAY HAVE ONGOING
CONVECTION ALONG AND NORTH OF THE WARM FRONT ACROSS NORTHERN
KANSAS AT THE BEGINNING OF THE PERIOD AS WELL. 0-6KM WIND SHEAR
VECTORS GENERALLY 50-60KTS BUT DIRECTIONAL TURNING IS NOT AS
IMPRESSIVE. GIVEN INSTABILITY GENERALLY 800-1200J/KG THINK THAT
MAIN CONCERN WILL BE WINDS WITH THE STORMS AS THE LINE PASSES.
SOME LOCALLY HEAVY RAIN ALSO POSSIBLE AND CANNOT RULE OUT ISOLATED
TORNADOES ALONG THE LINE...BUT AT THIS TIME IS NOT THE PRIMARY
CONCERN. TRAILING RAIN AND ISOLATED T CONTINUE THROUGH THE NIGHT.
NEXT CONCERN IS COLD AIR DIVING SOUTHWARD BEHIND THIS SYSTEM. WARM
NOSE IS INITIALLY SO WARM THINK THAT PRECIP WILL STAY AS RAIN
DESPITE COOLING SURFACE TEMPERATURES...BUT AS THIS NOSE COOLS
THEN MORE COMPLEX PRECIP TYPES COME INTO PLAY. BY THE TIME IT GETS
COLD ENOUGH ALOFT FOR SNOW...THE MOISTURE AND LIFT ARE GENERALLY
EAST OF THE AREA. AS THE COLD AIR AT THE SURFACE GETS COLDER...THE
CHANCE FOR A CHANGEOVER TO SLEET OR FREEZING RAIN ALSO INCREASES.
HAVE STARTED WITH A RAIN SNOW MIX ACROSS THE NORTHWEST...BUT THINK
THIS WILL BE MORE OF A MIXED BAG...WITH LITTLE OF IT STICKING TO
THE GROUND AND ANY ACCUMULATION ON ELEVATED SURFACES. INITIAL
CHANCES FOR MIXED PRECIP ARE NORTH AND WEST OF MANHATTAN AFTER
MIDNIGHT INTO WEDNESDAY MORNING...RETREATING SOMEWHAT BACK INTO
NORTH CENTRAL KANSAS WEDNESDAY AFTERNOON. THE CHANCES THEN SPREAD
EASTWARD WITH A MIX POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING
ACROSS MUCH OF NORTHEAST AND EAST CENTRAL KANSAS. WILL HAVE TO
MONITOR FORECAST SOUNDINGS OVER NEXT FEW RUNS...BUT A QUICK ROUND
OF SOME TYPE OF FREEZING PRECIP LOOKS POSSIBLE FOR NORTH CENTRAL
KANSAS.
THE AIRMASS THAT DROPS INTO THE PLAINS BEHIND THE FRONT HOLDS
HIGHS IN THE 30S AND 40S WEDNESDAY...40S FOR THURSDAY...SLOWLY
RISING TOWARD 50 ON FRIDAY AND BACK TOWARD NORMAL LATER IN THE
WEEKEND. OVERNIGHT LOW TEMPERATURES MAY FALL BELOW FREEZING
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...FINALLY RISING BACK INTO
THE 40S SATURDAY NIGHT. ALTHOUGH THE GROWING SEASON IS SLOW TO
START...ITS WORTH NOTING THAT EARLY EMERGENT VEGETATION WILL SEE
COLD OVERNIGHT LOWS MID TO LATE WEEK. 67
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 631 PM CDT MON APR 8 2013
FOR 00Z TAFS...BORDERLINE VFR/MVFR CONDITIONS EXPECTED EARLY THIS
EVENING. HOWEVER...THE STEADY SOUTHERLY FLOW WILL ADVECT MORE
MOISTURE INTO THE REGION THIS EVENING AND OVERNIGHT...RESULTING IN
WIDESPREAD MVFR CIGS AND POSSIBLY A PERIOD OF IFR CIGS THROUGH
SUNRISE. WHILE THERE IS A CHANCE FOR A FEW SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP IN THE AREA TONIGHT AND OVERNIGHT...CONFIDENCE IN
TIMING AND LOCATION IS TOO LOW AT THIS TIME TO WARRANT INCLUDING IN
THE TAF. MVFR CONDITIONS EXPECTED THROUGH THE DAY ON TUESDAY AHEAD
OF A COLD FRONT THAT WILL PASS THROUGH THE TAF SITES TUESDAY
EVENING.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
324 PM CDT SUN APR 7 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM CDT SUN APR 7 2013
TIMING OF CONVECTION DOSE NOT APPEAR TO BE MUCH DIFFERENT FROM THE
PREV FORECAST WITH THE UPPER DISTURBANCE EXPECTED TO MOVE ACROSS
THE AREA THROUGH THE EVENING. BIGGEST UNCERTAINTY IS WITH CIGS
OVERNIGHT. BOTH THE MET AND MAV OBJECTIVE GUIDANCE IS BRINGING
LIFT CIGS IN WITH CONTINUED LOW LEVEL MOISTURE ADVECTION.
CONFIDENCE IS MARGINAL...SO LEFT THE FORECAST FOR MVFR CIGS AFTER
THE PRECIP. LATER SHIFTS CAN REEVALUATE THE LIFR CIGS POTENTIAL.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1234 PM CDT SUN APR 7 2013
.SHORT TERM...(TODAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
TODAY...DEEPER MOISTURE EXTENDING FROM SOUTHERN OK AND EAST TX
WILL BE ADVECTED NORTHWARD AS A LEE SURFACE TROUGH DEEPENS ACROSS
THE CENTRAL AND WESTERN HIGH PLAINS. THE SOUTHERLY LOW- LEVEL FLOW
WILL ADVECT THIS DEEPER MOISTURE NORTHWARD ACROSS EASTERN KS LATE
THIS AFTERNOON.
THE WESTERN GULF OF MEXICO IS NOT AT EQUILIBRIUM EARLY THIS
MORNING...BUT THE RESIDUAL MOISTURE RETURN SHOULD BE SUFFICIENT TO
ALLOW MID TO UPPER 50 DEWPOINTS TO ADVECT NORTHWARD ACROSS THE CWA
BY LATE AFTERNOON.
MEANWHILE...A SHORTWAVE LENGTH H5 TROUGH WAS MOVING EASTWARD ACROSS
CENTRAL CO...SOUTHWARD INTO NORTHWEST NM. THE NAM...ECMWF AND GFS
SHOW THIS H5 TROUGH MOVING EAST ACROSS WESTERN AND CENTRAL KS TODAY.
STRONGER ASCENT AHEAD OF THIS H5 TROUGH AND THE STRONGER ISENTROPIC
LIFT ON THE NORTH SIDE OF DEEPER MOISTURE RETURN WILL ALLOW
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP FROM
SOUTH TO NORTH ACROSS THE CWA DURING THE MID AND LATE AFTERNOON
HOURS.
THE VERTICAL WIND SHEAR LOOKS TO BE STRONG WITH 0-6KM SHEAR OF 40 TO
60 KTS ACROSS THE CWA THROUGH THE LATE AFTERNOON HOURS. INSTABILITY
WILL INCREASE THROUGH THE AFTERNOON AS THE DEEPER MOISTURE ADVECTS
NORTHWARD TO AT LEAST I-70. GIVEN STEEP LAPSE RATES FROM 700MB TO
THE SURFACE...ONCE THE DEEPER MOISTURE ADVECT FAR ENOUGH NORTH WE
SHOULD SEE SBCAPE INCREASE TO 1,000 TO 1,500 J/KG FROM I-70 SOUTH.
THE NAM MODEL EVEN SHOWS AN ENHANCED BAND OF 0-1KM SRH OF 80-100
J/KG ALONG THE I-35 CORRIDOR BY 21Z AND LIFTING NORTHWARD TO I-70 BY
00Z. THIS WOULD BE SUFFICIENT FOR DISCRETE SUPERCELL TO POTENTIALLY
PRODUCE ISOLATED TORNADOES. HOWEVER...THE MODE OF CONVECTION IS
STILL IN QUESTION. THE ECMWF...GFS...AND NAM ALL SHOW NUMEROUS
THUNDERSTORMS DEVELOPING ALONG I-35 AFTER 21Z AND EXTENDING WESTWARD
TOWARDS ICT. IF A COMPLEX OR CLUSTER OF THUNDERSTORMS DEVELOPS LATE
IN THE AFTERNOON HOURS ALONG THE NORTHERN EDGE OF DEEPER MOISTURE
RETURN...THEN THE PRIMARY THREAT WILL LARGE HAIL AND SEVERE WIND
GUSTS. THIS COMPLEX OF STORMS WILL DEVELOP NORTHWARD ACROSS EAST
CENTRAL KS LATE IN THE AFTERNOON. IF THE THUNDERSTORMS REMAIN
DISCRETE...THEN GIVEN THE 0-1KM SRH AND INSTABILITY...THEN ISOLATED
TORNADOES COULD NOT BE RULED OUT FOR PORTIONS OF THE CWA...SOUTH OF
I-70. THE RAP AND (ARW) WRF...TWO OF OUR MESOSCALE MODELS...SHOW THE
INITIATION OF DEEP MOIST CONVECTION WEST AND SOUTHWEST OF THE CWA
THROUGH THE LATE AFTERNOON HOURS. THE INITIAL MODE LOOKS DISCRETE
WITH STORM MERGERS OCCURRING AS THEY MOVE NORTHEAST ACROSS THE CWA
DURING THE EARLY EVENING HOURS. STAY TUNED TO LATER UPDATES ON THE
POTENTIAL FOR SEVERE WEATHER LATE THIS AFTERNOON AND EVENING.
TEMPERATURES WILL WARM INTO THE LOWER TO MID 70S WITH PATCHES OF
DENSE HIGH CLOUD COVER SPREADING ACROSS THE CWA THIS MORNING. CU
SHOULD BEGIN TO DEVELOP AS THE DEEPER MOISTURE SURGES NORTHWARD THIS
AFTERNOON.
GARGAN
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
CONVECTIVE COMPLEX OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP/EXPAND EAST AND NORTHEAST ACROSS PRIMARILY THE SOUTHEAST
HALF OF THE CWA THROUGH THE EARLY AND MID EVENING HOURS WITH A
THREAT FOR PRIMARILY LARGE HAIL WITH THE STRONGER STORMS.
HOWEVER...AS THE SHORTWAVE TROUGH MOVES THROUGH BY LATE
EVENING...THE LLVL FLOW WILL BEGIN TO VEER AND ALLOW FOR SOME DRIER
AIR TO ADVECT EASTWARD WHICH WILL FAVOR THE MORE EASTWARD
PROGRESSION OF THE POSSIBLE MCS. HAVE THEREFORE TRENDED THE HIGHER
POPS THROUGH THE EARLY/MID EVENING...THEN A GRADUAL DECREASED POP
THROUGH LATE EVENING/MIDNIGHT...THEN A MUCH MORE RAPID DROP IN POPS
AFTER MIDNIGHT WEST TO EAST ACROSS THE CWA. WILL KEEP THE SOUTHEAST
CWA WARMER WITH THE CLOUDS AND HIGHER DEWPOINTS IN THE UPPER 50S
WITH NEAR 50 IN THE FAR NORTH CENTRAL.
ON MONDAY...OVERALL LACK OF LARGE SCALE ASCENT/FORCING WITHIN AN
ENVIRONMENT EXHIBITING A RAPIDLY STRENGTHENING ELEVATED MIXED LAYER
(EML) DOES NOT INCREASE CONFIDENCE IN CARRYING POPS BEYOND LOW END
CHANCE CATEGORY. HAVE REMOVED POPS FOR MOST OF THE MORNING...BUT
CARRIED LOW POPS IN THE LATE MORNING/AFTERNOON...ALTHOUGH IMPRESSIVE
INHIBITION MAY WARRANT LOWERING/OR REMOVING POPS MORE. KEPT HIGHS IN
THE LOW TO MID 70S DUE TO EXPECTED STRATUS DECK BENEATH
INVERSION.
BY MONDAY NIGHT...MORE CONVECTION IS EXPECTED TO ADVANCE/DEVELOP
EASTWARD FROM WESTERN/CENTRAL KANSAS THROUGH THE NIGHT PRIMARILY
ALONG THE NORTH OF THE WARM FRONT AS LLVL JET INCREASES THROUGH THE
NIGHT. THE FOCUS FOR THIS HAS CONTINUES TO TREND NORTHWARD WITH
TIME AND STRONG CAPPING OVER THE CWA MAY ALSO INHIBIT THE SOUTH AND
EASTWARD EXTENT OF THE CONVECTION AS WELL. FOR NOW...HAVE KEPT
LIKELY POPS ACROSS THE NORTHERN 2/3 OF THE CWA...BUT IF MODEL TRENDS
CONTINUE...THE HIGHER POPS MAY NEED TO BE TRIMMED/SHIFTED MORE
NORTHWARD CLOSER TO THE NE BORDER.
TUESDAY AND TUESDAY NIGHT STILL APPEARS TO BE THE MOST ACTIVE
TIME FRAME FOR THIS STORM SYSTEM ACROSS OUR CWA AS A DEEPENING SFC
LOW/COLD FRONT ADVANCES EASTWARD ACROSS THE AREA AS THE MAIN
SHORTWAVE ROTATES NORTHEAST OUT OF THE LONGER WAVE TROUGH IN THE
WEST INTO THE NORTHERN PLAINS EARLY WEDNESDAY. CONVECTION COULD
FIRST INITIATE OVER CENTRAL KS THEN CONGEAL INTO A POSSIBLE SQUALL
LINE AS IT MOVES EAST THROUGH THE AFTERNOON/EVENING WITH ALL MODES
OF SEVERE WEATHER POSSIBLE DURING THIS TIME FRAME BEFORE THE FRONT
USHERS IN COOLER AND DRIER AIR INTO EASTERN KS LATE IN THE NIGHT.
WILL KEEP A LINGERING CHANCE FOR DECREASING CONVECTION/RAIN
POTENTIAL ON WEDNESDAY WITH SHOWERS EXITING THE CWA WEDNESDAY
NIGHT...THEN DRY THURSDAY INTO FRIDAY NIGHT. A SLIGHT CHANCE FOR
SHOWERS WILL RETURN BY SATURDAY. AFTER HIGHS IN THE 60S/70S ON
TUESDAY...WEDNESDAY TEMPS WILL COOL INTO THE 40S AND 50S FOR
WEDNESDAY AND THURSDAY...THEN THE 50S FRIDAY AND THE 60S FOR
SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM CDT SUN APR 7 2013
TIMING OF CONVECTION DOSE NOT APPEAR TO BE MUCH DIFFERENT FROM THE
PREV FORECAST WITH THE UPPER DISTURBANCE EXPECTED TO MOVE ACROSS
THE AREA THROUGH THE EVENING. BIGGEST UNCERTAINTY IS WITH CIGS
OVERNIGHT. BOTH THE MET AND MAV OBJECTIVE GUIDANCE IS BRINGING
LIFT CIGS IN WITH CONTINUED LOW LEVEL MOISTURE ADVECTION.
CONFIDENCE IS MARGINAL...SO LEFT THE FORECAST FOR MVFR CIGS AFTER
THE PRECIP. LATER SHIFTS CAN REEVALUATE THE LIFR CIGS POTENTIAL.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS WICHITA KS
931 AM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 922 AM CDT SUN APR 7 2013
PERSISTENT WARM AIR ADVECTION CONTINUES GENERATE BANDS OF VERY
LIGHT RAIN ACROSS CENTRAL KANSAS. LOW LEVELS REMAIN SOMEWHAT
DRY...THUS MOST PRECIPITATION EVAPORATING BEFORE REACHING THE GROUND.
UPDATED FORECAST TO INCLUDE SLIGHT CHANCE POPS...THOUGH EXPECT MOST
LOCATIONS TO REMAIN DRY.
SUBSIDENCE BEHIND SHOWERS COMBINED WITH MIXING...PRODUCING A
TEMPORARY BOOST AREAR OF RAIN BANDS. TIMING AND AMOUNT OF WARMING DIFFICULT
TO FORECAST...AND ATTEMPTED TO EMULATE...WITH HRRR PROVIDING BEST GUIDANCE.
SF
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 300 AM CDT SUN APR 7 2013
CURRENT SATELLITE WATER VAPOR IMAGERY SHOWS UPPER WAVE OVER NORTHERN
NEVADA/SOUTHERN IDAHO RACING EASTWARD VIA ZONAL UPPER FLOW REGIME.
THE ENVIRONMENT LOOKS CAPPED FOR SURFACE BASED ACTIVITY AND NOT
SEEING ANY REAL GOOD LOW LEVEL CONVERGENCE...HOWEVER WARM AIR
ADVECTION IN THE MID-LEVELS AHEAD OF APPROACHING PV WAVE SHOULD
SPARK OFF SCATTERED ELEVATED SHOWERS/STORMS TODAY. ELEVATED
INSTABILITY/SHEAR COMBO SUGGESTS A FEW STRONG STORMS TO POSSIBLY
MARGINALLY SEVERE FOR THIS AFTERNOON/EVENING WITH HAIL BEING THE
MAIN HAZARD. THIS ACTIVITY WILL MOVE NORTHEAST TONIGHT WITH A LULL
IN THE ACTIVITY FOR MONDAY...AS SHORT WAVE RIDGING COMMENCES
ALOFT. STILL THINK MODELS MIGHT BE A LITTLE OVER ZEALOUS ON
QUALITY OF MOISTURE RETURN FOR MONDAY. GIVEN NO REAL LOW-LEVEL
FOCUS AND STRONG CAPPING OVER THE REGION ON MONDAY WOULD EXPECT
ANY AFTERNOON ACTIVITY TO DEVELOP OVER NORTHWEST KANSAS IN THE
UPSLOPE REGIME. THE BETTER CHANCES OF THUNDERSTORMS FOR LATE
MONDAY AFTERNOON/NIGHT WILL BE OVER CENTRAL KANSAS AND POINTS
NORTH...AS LIFT AND MOISTURE TRANSPORT IS FAVORED NEAR WARM FRONT
BOUNDARY. SEVERE WEATHER LOOKS MORE LIKELY ON TUESDAY AS MAIN
UPPER WAVE MOVES TOWARDS THE CENTRAL PLAINS. THE MOST LIKELY MODE
OF THUNDERSTORMS STILL SEEMS TO BE A LINE OF STRONG TO SEVERE
THUNDERSTORMS MATERIALIZING TUESDAY AFTERNOON ALONG THE FRONT...AS
DEEP MERIDIONAL TROUGHING AND STRONG UPPER DYNAMICS FAVOR LINEAR
ACTIVITY.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN APR 7 2013
LINGERING PRECIPITATION FOR WEDNESDAY WITH POSSIBLE RAIN/SNOW
MIXTURE EARLY WEDNESDAY MORNING FOR CENTRAL KANSAS...FOLLOWED BY MUCH
COOLER TEMPERATURES FOR WEDNESDAY/THURSDAY AND WARMER WEATHER TO
RETURN FOR NEXT WEEKEND.
JAKUB
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 646 AM CDT SUN APR 7 2013
DIFFICULT AVIATION FORECAST. NOT MUCH AGREEMENT BETWEEN MODELS
WITH FINER DETAILS THAT WOULD SIGNIFICANTLY IMPACT AVIATION
FORECASTS. SOME CHANCE FOR LIGHT PRECIPITATION AT KRSL/KSLN THIS
MORNING FROM MID LEVEL CLOUD DECK. RAIN SHOWERS/THUNDERSTORMS ALSO
POSSIBLE LATE THIS AFTERNOON/EVENING AT KICT/KHUT/KCNU...BUT
UNCERTAINTY...TIMING AND COVERAGE PRECLUDE MENTIONING AT THIS
TIME. MODELS ALL SHOW LOW LEVEL MOISTURE ON THE INCREASE DURING
THE FORECAST...AND SUSPECT AT LEAST MVFR CEILINGS WILL BE LIKELY
AT ALL SITES BY END OF THE VALID PERIOD...IF NOT IFR. -HOWERTON
&&
.FIRE WEATHER...
ISSUED AT 646 AM CDT SUN APR 7 2013
GRASSLAND FIRE DANGER INDEX MAY BRIEFLY GO INTO THE VERY HIGH
CATEGORY ON TUESDAY AFTERNOON OVER PARTS OF CENTRAL AND SOUTH
CENTRAL KANSAS. HOWEVER PRECIPITATION MAY LIMIT THIS THREAT.
WINDS MAY BE GUSTY AT TIMES. CONFIDENCE IN FORECAST IS NOT
PARTICULARLY HIGH DUE TO MODEL UNCERTAINTY. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 72 58 75 60 / 40 30 10 30
HUTCHINSON 72 56 75 59 / 40 30 10 40
NEWTON 71 56 74 59 / 60 40 10 40
ELDORADO 72 58 74 60 / 50 40 10 30
WINFIELD-KWLD 72 58 76 61 / 30 20 10 20
RUSSELL 71 53 74 55 / 50 30 40 60
GREAT BEND 72 55 75 56 / 40 30 30 50
SALINA 72 55 72 58 / 60 50 30 60
MCPHERSON 72 56 74 58 / 50 40 20 50
COFFEYVILLE 72 59 74 62 / 30 40 10 20
CHANUTE 72 58 72 60 / 50 60 10 20
IOLA 72 58 72 60 / 60 70 10 30
PARSONS-KPPF 72 59 73 61 / 30 40 10 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
716 AM CDT SUN APR 7 2013
.SHORT TERM...(TODAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
TODAY...DEEPER MOISTURE EXTENDING FROM SOUTHERN OK AND EAST TX
WILL BE ADVECTED NORTHWARD AS A LEE SURFACE TROUGH DEEPENS ACROSS
THE CENTRAL AND WESTERN HIGH PLAINS. THE SOUTHERLY LOW- LEVEL FLOW
WILL ADVECT THIS DEEPER MOISTURE NORTHWARD ACROSS EASTERN KS LATE
THIS AFTERNOON.
THE WESTERN GULF OF MEXICO IS NOT AT EQUILIBRIUM EARLY THIS
MORNING...BUT THE RESIDUAL MOISTURE RETURN SHOULD BE SUFFICIENT TO
ALLOW MID TO UPPER 50 DEWPOINTS TO ADVECT NORTHWARD ACROSS THE CWA
BY LATE AFTERNOON.
MEANWHILE...A SHORTWAVE LENGTH H5 TROUGH WAS MOVING EASTWARD ACROSS
CENTRAL CO...SOUTHWARD INTO NORTHWEST NM. THE NAM...ECMWF AND GFS
SHOW THIS H5 TROUGH MOVING EAST ACROSS WESTERN AND CENTRAL KS TODAY.
STRONGER ASCENT AHEAD OF THIS H5 TROUGH AND THE STRONGER ISENTROPIC
LIFT ON THE NORTH SIDE OF DEEPER MOISTURE RETURN WILL ALLOW
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP FROM
SOUTH TO NORTH ACROSS THE CWA DURING THE MID AND LATE AFTERNOON
HOURS.
THE VERTICAL WINDSHEAR LOOKS TO BE STRONG WITH 0-6KM SHEAR OF 40 TO
60 KTS ACROSS THE CWA THROUGH THE LATE AFTERNOON HOURS. INSTABILITY
WILL INCREASE THROUGH THE AFTERNOON AS THE DEEPER MOISTURE ADVECTS
NORTHWARD TO AT LEAST I-70. GIVEN STEEP LAPSE RATES FROM 700MB TO
THE SURFACE...ONCE THE DEEPER MOISTURE ADVECT FAR ENOUGH NORTH WE
SHOULD SEE SBCAPE INCREASE TO 1,000 TO 1,500 J/KG FROM I-70 SOUTH.
THE NAM MODEL EVEN SHOWS AN ENHANCED BAND OF 0-1KM SRH OF 80-100
J/KG ALONG THE I-35 CORRIDOR BY 21Z AND LIFTING NORTHWARD TO I-70 BY
00Z. THIS WOULD BE SUFFICIENT FOR DISCRETE SUPERCELL TO POTENTIALLY
PRODUCE ISOLATED TORNADOES. HOWEVER...THE MODE OF CONVECTION IS
STILL IN QUESTION. THE ECMWF...GFS...AND NAM ALL SHOW NUMEROUS
THUNDERSTORMS DEVELOPING ALONG I-35 AFTER 21Z AND EXTENDING WESTWARD
TOWARDS ICT. IF A COMPLEX OR CLUSTER OF THUNDERSTORMS DEVELOPS LATE
IN THE AFTERNOON HOURS ALONG THE NORTHERN EDGE OF DEEPER MOISTURE
RETURN...THEN THE PRIMARY THREAT WILL LARGE HAIL AND SEVERE WIND
GUSTS. THIS COMPLEX OF STORMS WILL DEVELOP NORTHWARD ACROSS EAST
CENTRAL KS LATE IN THE AFTERNOON. IF THE THUNDERSTORMS REMAIN
DISCRETE...THEN GIVEN THE 0-1KM SRH AND INSTABILITY...THEN ISOLATED
TORNADOES COULD NOT BE RULED OUT FOR PORTIONS OF THE CWA...SOUTH OF
I-70. THE RAP AND (ARW) WRF...TWO OF OUR MESOSCALE MODELS...SHOW THE
INITIATION OF DEEP MOIST CONVECTION WEST AND SOUTHWEST OF THE CWA
THROUGH THE LATE AFTERNOON HOURS. THE INITIAL MODE LOOKS DISCRETE
WITH STORM MERGERS OCCURING AS THEY MOVE NORTHEAST ACROSS THE CWA
DURING THE EARLY EVENING HOURS. STAY TUNED TO LATER UPDATES ON THE
POTENTIAL FOR SEVERE WEATHER LATE THIS AFTERNOON AND EVENING.
TEMPERATURES WILL WARM INTO THE LOWER TO MID 70S WITH PATCHES OF
DENSE HIGH CLOUD COVER SPREADING ACROSS THE CWA THIS MORNING. CU
SHOULD BEGIN TO DEVELOP AS THE DEEPER MOISTURE SURGES NORTHWARD THIS
AFTERNOON.
GARGAN
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
CONVECTIVE COMPLEX OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP/EXPAND EAST AND NORTHEAST ACROSS PRIMARILY THE SOUTHEAST
HALF OF THE CWA THROUGH THE EARLY AND MID EVENING HOURS WITH A
THREAT FOR PRIMARILY LARGE HAIL WITH THE STRONGER STORMS.
HOWEVER...AS THE SHORTWAVE TROUGH MOVES THROUGH BY LATE
EVENING...THE LLVL FLOW WILL BEGIN TO VEER AND ALLOW FOR SOME DRIER
AIR TO ADVECT EASTWARD WHICH WILL FAVOR THE MORE EASTWARD
PROGRESSION OF THE POSSIBLE MCS. HAVE THEREFORE TRENDED THE HIGHER
POPS THROUGH THE EARLY/MID EVENING...THEN A GRADUAL DECREASED POP
THROUGH LATE EVENING/MIDNIGHT...THEN A MUCH MORE RAPID DROP IN POPS
AFTER MIDNIGHT WEST TO EAST ACROSS THE CWA. WILL KEEP THE SOUTHEAST
CWA WARMER WITH THE CLOUDS AND HIGHER DEWPOINTS IN THE UPPER 50S
WITH NEAR 50 IN THE FAR NORTH CENTRAL.
ON MONDAY...OVERALL LACK OF LARGE SCALE ASCENT/FORCING WITHIN AN
ENVIRONMENT EXHIBITING A RAPIDLY STRENGTHENING ELEVATED MIXED LAYER
(EML) DOES NOT INCREASE CONFIDENCE IN CARRYING POPS BEYOND LOW END
CHANCE CATEGORY. HAVE REMOVED POPS FOR MOST OF THE MORNING...BUT
CARRIED LOW POPS IN THE LATE MORNING/AFTERNOON...ALTHOUGH IMPRESSIVE
INHIBITION MAY WARRANT LOWERING/OR REMOVING POPS MORE. KEPT HIGHS IN
THE LOW TO MID 70S DUE TO EXPECTED STRATUS DECK BENEATH
INVERSION.
BY MONDAY NIGHT...MORE CONVECTION IS EXPECTED TO ADVANCE/DEVELOP
EASTWARD FROM WESTERN/CENTRAL KANSAS THROUGH THE NIGHT PRIMARILY
ALONG THE NORTH OF THE WARM FRONT AS LLVL JET INCREASES THROUGH THE
NIGHT. THE FOCUS FOR THIS HAS CONTINUES TO TREND NORTHWARD WITH
TIME AND STRONG CAPPING OVER THE CWA MAY ALSO INHIBIT THE SOUTH AND
EASTWARD EXTENT OF THE CONVECTION AS WELL. FOR NOW...HAVE KEPT
LIKELY POPS ACROSS THE NORTHERN 2/3 OF THE CWA...BUT IF MODEL TRENDS
CONTINUE...THE HIGHER POPS MAY NEED TO BE TRIMMED/SHIFTED MORE
NORTHWARD CLOSER TO THE NE BORDER.
TUESDAY AND TUESDAY NIGHT STILL APPEARS TO BE THE MOST ACTIVE
TIMEFRAME FOR THIS STORM SYSTEM ACROSS OUR CWA AS A DEEPENING SFC
LOW/COLD FRONT ADVANCES EASTWARD ACROSS THE AREA AS THE MAIN
SHORTWAVE ROTATES NORTHEAST OUT OF THE LONGER WAVE TROUGH IN THE
WEST INTO THE NORTHERN PLAINS EARLY WEDNESDAY. CONVECTION COULD
FIRST INITIATE OVER CENTRAL KS THEN CONGEAL INTO A POSSIBLE SQUALL
LINE AS IT MOVES EAST THROUGH THE AFTERNOON/EVENING WITH ALL MODES
OF SEVERE WEATHER POSSIBLE DURING THIS TIME FRAME BEFORE THE FRONT
USHERS IN COOLER AND DRIER AIR INTO EASTERN KS LATE IN THE NIGHT.
WILL KEEP A LINGERING CHANCE FOR DECREASING CONVECTION/RAIN
POTENTIAL ON WEDNESDAY WITH SHOWERS EXITING THE CWA WEDNESDAY
NIGHT...THEN DRY THURSDAY INTO FRIDAY NIGHT. A SLIGHT CHANCE FOR
SHOWERS WILL RETURN BY SATURDAY. AFTER HIGHS IN THE 60S/70S ON
TUESDAY...WEDNESDAY TEMPS WILL COOL INTO THE 40S AND 50S FOR
WEDNESDAY AND THURSDAY...THEN THE 50S FRIDAY AND THE 60S FOR
SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 711 AM CDT SUN APR 7 2013
EXPECT VFR CONDITIONS FOR THE NEXT 12 HOURS. THIS EVENING MVFR
CEILINGS SHOULD DEVELOP ALONG WITH SHOWER AND THUNDERSTORMS. THUNDERSTORMS
SHOULD MOVE EAST OF THE TAF SITES AFTER 6Z MON. THERE MAY BE SOME
BRIEF LOW MVFR OR IFR CONDITIONS MAY OCCUR WITH THE STRONGER
THUNDERSTORMS THIS EVENING. MVFR STRATUS WILL CONTINUE THROUGH 12Z
MON.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
447 AM CDT SUN APR 7 2013
.SHORT TERM...(TODAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
TODAY...DEEPER MOISTURE ALONG EXTENDING FROM SOUTHERN OK AND EAST TX
WILL BE ADVECTED NORTHWARD AS A LEE SURFACE TROUGH DEEPENS ACROSS
THE CENTRAL AND WESTERN HIGH PLAINS. THE SOUTHERLY LOW-LEVEL FLOW
WILL ADVECT THIS DEEPER MOISTURE NORTHWARD ACROSS EASTERN KS LATE
THIS AFTERNOON.
THE WESTERN GULF OF MEXICO IS NOT AT EQUILIBRIUM EARLY THIS
MORNING...BUT THE RESIDUAL MOISTURE RETURN SHOULD BE SUFFICIENT TO
ALLOW MID TO UPPER 50 DEWPOINTS TO ADVECT NORTHWARD ACROSS THE CWA
BY LATER AFTERNOON.
MEANWHILE...A SHORTWAVE LENGTH H5 TROUGH WAS MOVING EASTWARD ACROSS
CENTRAL CO...SOUTHWARD INTO NORTHWEST NM. THE NAM...ECMWF AND GFS
SHOW THIS H5 TROUGH MOVING EAST ACROSS WESTERN AND CENTRAL KS TODAY.
STRONGER ASCENT AHEAD OF THIS H5 TROUGH AND THE STRONGER ISENTROPIC
LIFT ON THE NORTH SIDE OF DEEPER MOISTURE RETURN WILL ALLOW
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP FROM
SOUTH TO NORTH ACROSS THE CWA DURING THE MID AND LATE AFTERNOON
HOURS.
THE VERTICAL WINDSHEAR LOOKS TO BE STRONG WITH 0-6KM SHEAR OF 40 TO
60 KTS ACROSS THE CWA THROUGH THE LATE AFTERNOON HOURS. INSTABILITY
WILL INCREASE THROUGH THE AFTERNOON AS THE DEEPER MOISTURE ADVECTS
NORTHWARD TO AT LEAST I-70. GIVEN STEEP LAPSE RATES FROM 700MB TO
THE SURFACE...ONCE THE DEEPER MOISTURE ADVECT FAR ENOUGH NORTH WE
SHOULD SEE SBCAPE INCREASE TO 1,000 TO 1,500 J/KG FROM I-70 SOUTH.
THE NAM MODEL EVEN SHOWS AN ENHANCED BAND OF 0-1KM SRH OF 80-100
J/KG ALONG THE I-35 CORRIDOR BY 21Z AND LIFTING NORTHWARD TO I-70 BY
00Z. THIS WOULD BE SUFFICIENT FOR DISCRETE SUPERCELL TO POTENTIALLY
PRODUCE ISOLATED TORNADOES. HOWEVER...THE MODE OF CONVECTION IS
STILL IN QUESTION. THE ECMWF...GFS...AND NAM ALL SHOW NUMEROUS
THUNDERSTORMS DEVELOPING ALONG I-35 AFTER 21Z AND EXTENDING WESTWARD
TOWARDS ICT. IF A COMPLEX OR CLUSTER OF THUNDERSTORMS DEVELOPS LATE
IN THE AFTERNOON HOURS ALONG THE NORTHERN EDGE OF DEEPER MOISTURE
RETURN...THEN THE PRIMARY THREAT WILL LARGE HAIL AND SEVERE WIND
GUSTS. THIS COMPLEX OF STORMS WILL DEVELOP NORTHWARD ACROSS EAST
CENTRAL KS LATE IN THE AFTERNOON. IF THE THUNDERSTORMS REMAIN
DISCRETE...THEN GIVEN THE 0-1KM SRH AND INSTABILITY...THEN ISOLATED
TORNADOES COULD NOT BE RULED OUT FOR PORTIONS OF THE CWA...SOUTH OF
I-70. THE RAP AND (ARW) WRF...TWO OF OUR MESOSCALE MODELS...SHOW THE
INITIATION OF DEEP MOIST CONVECTION WEST AND SOUTHWEST OF THE CWA
THROUGH THE LATE AFTERNOON HOURS. THE INITIAL MODE LOOKS DISCRETE
WITH STORM MERGERS OCCURING AS THEY MOVE NORTHEAST ACROSS THE CWA
DURING THE EARLY EVENING HOURS. STAY TUNED TO LATER UPDATES ON THE
POTENTIAL FOR SEVERE WEATHER LATE THIS AFTERNOON AND EVENING.
TEMPERATURES WILL WARM INTO THE LOWER TO MID 70S WITH PATCHES OF
DENSE HIGH CLOUD COVER SPREADING ACROSS THE CWA THIS MORNING. CU
SHOULD BEGIN TO DEVELOP AS THE DEEPER MOISTURE SURGES NORTHWARD THIS
AFTERNOON.
GARGAN
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 442 AM CDT SUN APR 7 2013
CONVECTIVE COMPLEX OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP/EXPAND EAST AND NORTHEAST ACROSS PRIMARILY THE SOUTHEAST
HALF OF THE CWA THROUGH THE EARLY AND MID EVENING HOURS WITH A
THREAT FOR PRIMARILY LARGE HAIL WITH THE STRONGER STORMS.
HOWEVER...AS THE SHORTWAVE TROUGH MOVES THROUGH BY LATE
EVENING...THE LLVL FLOW WILL BEGIN TO VEER AND ALLOW FOR SOME DRIER
AIR TO ADVECT EASTWARD WHICH WILL FAVOR THE MORE EASTWARD
PROGRESSION OF THE POSSIBLE MCS. HAVE THEREFORE TRENDED THE HIGHER
POPS THROUGH THE EARLY/MID EVENING...THEN A GRADUAL DECREASED POP
THROUGH LATE EVENING/MIDNIGHT...THEN A MUCH MORE RAPID DROP IN POPS
AFTER MIDNIGHT WEST TO EAST ACROSS THE CWA. WILL KEEP THE SOUTHEAST
CWA WARMER WITH THE CLOUDS AND HIGHER DEWPOINTS IN THE UPPER 50S
WITH NEAR 50 IN THE FAR NORTH CENTRAL.
ON MONDAY...OVERALL LACK OF LARGE SCALE ASCENT/FORCING WITHIN AN
ENVIRONMENT EXHIBITING A RAPIDLY STRENGTHENING ELEVATED MIXED LAYER
(EML) DOES NOT INCREASE CONFIDENCE IN CARRYING POPS BEYOND LOW END
CHANCE CATEGORY. HAVE REMOVED POPS FOR MOST OF THE MORNING...BUT
CARRIED LOW POPS IN THE LATE MORNING/AFTERNOON...ALTHOUGH IMPRESSIVE
INHIBITION MAY WARRANT LOWERING/OR REMOVING POPS MORE. KEPT HIGHS IN
THE LOW TO MID 70S DUE TO EXPECTED STRATUS DECK BENEATH
INVERSION.
BY MONDAY NIGHT...MORE CONVECTION IS EXPECTED TO ADVANCE/DEVELOP
EASTWARD FROM WESTERN/CENTRAL KANSAS THROUGH THE NIGHT PRIMARILY
ALONG THE NORTH OF THE WARM FRONT AS LLVL JET INCREASES THROUGH THE
NIGHT. THE FOCUS FOR THIS HAS CONTINUES TO TREND NORTHWARD WITH
TIME AND STRONG CAPPING OVER THE CWA MAY ALSO INHIBIT THE SOUTH AND
EASTWARD EXTENT OF THE CONVECTION AS WELL. FOR NOW...HAVE KEPT
LIKELY POPS ACROSS THE NORTHERN 2/3 OF THE CWA...BUT IF MODEL TRENDS
CONTINUE...THE HIGHER POPS MAY NEED TO BE TRIMMED/SHIFTED MORE
NORTHWARD CLOSER TO THE NE BORDER.
TUESDAY AND TUESDAY NIGHT STILL APPEARS TO BE THE MOST ACTIVE
TIMEFRAME FOR THIS STORM SYSTEM ACROSS OUR CWA AS A DEEPENING SFC
LOW/COLD FRONT ADVANCES EASTWARD ACROSS THE AREA AS THE MAIN
SHORTWAVE ROTATES NORTHEAST OUT OF THE LONGER WAVE TROUGH IN THE
WEST INTO THE NORTHERN PLAINS EARLY WEDNESDAY. CONVECTION COULD
FIRST INITIATE OVER CENTRAL KS THEN CONGEAL INTO A POSSIBLE SQUALL
LINE AS IT MOVES EAST THROUGH THE AFTERNOON/EVENING WITH ALL MODES
OF SEVERE WEATHER POSSIBLE DURING THIS TIME FRAME BEFORE THE FRONT
USHERS IN COOLER AND DRIER AIR INTO EASTERN KS LATE IN THE NIGHT.
WILL KEEP A LINGERING CHANCE FOR DECREASING CONVECTION/RAIN
POTENTIAL ON WEDNESDAY WITH SHOWERS EXITING THE CWA WEDNESDAY
NIGHT...THEN DRY THURSDAY INTO FRIDAY NIGHT. A SLIGHT CHANCE FOR
SHOWERS WILL RETURN BY SATURDAY. AFTER HIGHS IN THE 60S/70S ON
TUESDAY...WEDNESDAY TEMPS WILL COOL INTO THE 40S AND 50S FOR
WEDNESDAY AND THURSDAY...THEN THE 50S FRIDAY AND THE 60S FOR
SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1212 AM CDT SUN APR 7 2013
FOR THE 06Z TAFS...WINDS HAVE BECOME LIGHT AND VARIABLE ACROSS THE
AREA THIS EVENING AND WILL REMAIN LIGHT THROUGH AROUND SUNRISE.
WINDS ARE EXPECTED TO INCREASE OUT OF THE SOUTH-SOUTHEAST LATER THIS
MORNING WITH INCREASING MID-LEVEL CLOUDS THROUGH THE DAY AS A LOW
PRESSURE SYSTEM APPROACHES THE AREA. COULD SEE SOME SHOWERS AND
THUNDERSTORMS DEVELOP OVER THE AREA DURING THE EVENING HOURS...WHICH
COULD LOWER CIGS/VIS TO MVFR CONDITIONS AND POSSIBLY LOWER. THERE IS
STILL UNCERTAINTY IN THE TIMING AND SCALE OF THIS
SHOWER/THUNDERSTORM ACTIVITY...SO WILL LIKELY NEED TO FINE TUNE THE
TIMING WITH FUTURE TAF UPDATES. AT THIS TIME THOUGH...MOST OF THE
ACTIVITY LOOKS TO BE MOVING EAST OF THE AREA BY AROUND 06Z.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
907 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 907 PM CDT MON APR 8 2013
HAVE UPDATED TWICE THIS EVENING TO CATCH UP TO TRENDS IN MOST
ELEMENTS. THE RUC SEEMS TO BE HANDLING THE SITUATION QUITE
WELL...SO FOLLOWED IT CLOSELY.
THE FIRST 2 ISSUES ARE THE RAPID SOUTH TO NORTH CLEARING...AND
THE WINDS ARE MUCH LIGHTER THAN MOST GUIDANCE WOULD INDICATE FOR
THE THIRD STRAIGHT NIGHT. OF COURSE THIS BRINGS GREATER
RADIATIONAL COOLING INTO PLAY. THE FINAL TREND OF LOWER 50
DEWPOINTS ADVECTING NORTHWARD OUT OF WEST TENNESSEE LEADS TO MORE
COOLING THAN PREVIOUSLY EXPECTED. KNOCKED LOWS DOWN A
CATEGORY...GENERALLY INTO THE UPPER 50S...BUT WOULD NOT BE SHOCKED
TO SEE A FEW SITES IN WEST KENTUCKY DROP INTO THE MIDDLE 50S.
UPDATE ISSUED AT 548 PM CDT MON APR 8 2013
UPDATE FOR 00Z AVIATION ONLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 329 PM CDT MON APR 8 2013
SREF AND NAM ARE TRENDING DRIER TONIGHT INTO TUESDAY...WHILE GFS
AND ECMWF SHOW WIDESPREAD LIGHT PRECIP LATE TONIGHT AND EARLY
TUESDAY. ECHOES THAT MOVED ACROSS OUR REGION TODAY PRODUCED MAINLY
SPRINKLES AT BEST. SREF AND NAM DID BETTER TODAY...AND IT SEEMS
LEANING TOWARD THE DRIER SOLUTIONS IN THE NEAR TERM IS A BETTER
BET...SO REMOVED POPS FOR TONIGHT AND TUESDAY. A STRAY SHOWER
ACROSS MAINLY OUR NORTHERN COUNTIES IS NOT OUT OF THE
QUESTION...BUT CHANCES JUST ARE NOT GOOD ENOUGH TO WARRANT A POP
AT THIS POINT.
THE LOW PRESSURE SYSTEM WILL BE MOVING CLOSER BY TUESDAY
NIGHT...AND MODELS ARE IN PRETTY GOOD AGREEMENT KEEPING OUR REGION
DRY THROUGH MIDNIGHT. DID INCLUDE SLIGHT CHANCE POPS FOR OUR
EXTREME WESTERN COUNTIES TUESDAY EVENING TO BETTER BLEND WITH OUR
NEIGHBORS. AFTER 06Z...MODELS SPREAD SOME LIGHT QPF INTO MUCH OF
SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI. WENT WITH LIKELY POPS
FAR WEST TO CHANCE AND SLIGHT CHANCE ACROSS MUCH OF SOUTHERN
ILLINOIS AND A GOOD PORTION OF SOUTHEAST MISSOURI...THOUGH QPF
AMOUNTS DO NOT LOOK TOO SIGNIFICANT AT THIS POINT.
TEMPERATURES WILL REMAIN UNSEASONABLY WARM THROUGH THE PERIOD.
LEANED ON THE WARM SIDE OF GUIDANCE FOR LOWS AND THE COOLER SIDE OF
GUIDANCE FOR HIGHS BASED ON WINDS STAYING UP AND EXPECTED CLOUD
COVER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 329 PM CDT MON APR 8 2013
THE MAIN FOCUS IN THIS TIME FRAME WILL COME WITH THE MID WEEK COLD
FRONT AND MID LEVEL SHORT WAVE THAT WILL BE APPROACHING THE MS RIVER
VALLEY LATE WED AND WED NIGHT. DETERMINISTIC MODEL RUNS OF THE
GFS/ECMWF ARE STILL NOT IN GOOD ENOUGH AGREEMENT REGARDING THE
TIMING OF THESE FEATURES TO HAVE A HIGH DEGREE OF CONFIDENCE AS TO
THE DEGREE OVER LOW LEVEL INSTABILITY THAT WILL BE AVAILABLE ONCE
THE FRONT ENTERS THE FORECAST AREA. THE OPERATIONAL GFS CONTINUES
TO BE THE QUICKEST/MOST PROGRESSIVE MODEL...THO IT HAS TRENDED
SLOWER FROM THE OVERNIGHT RUN. THUS...HAVE OPTED TO FOLLOW HPC/WPC
THOUGHTS AND SIDE A BIT MORE TOWARD THE SLOWER/MORE CONSISTENT 12Z
EURO RUN WITH THIS PACKAGE.
WITH THAT SAID...IT LOOKS AS THOUGH THE MAIN PUSH OF POTENTIAL
SEVERE STORMS AND/OR HEAVY RAINFALL WILL COME ALONG AND JUST BEHIND
THE COLD FRONT WED EVENING OVER SE MO...THEN LATER WED EVE INTO THE
OVERNIGHT AND EARLY AM HOURS THU EAST OF THE MS RIVER. EVEN THO LOW
LEVEL INSTABILITY WILL WANE DURING THE NIGHT TIME HOURS...IT STILL
APPEARS THAT AT LEAST MODEST INSTABILITY WILL PERSIST AHEAD OF THE
FRONT...ALONG WITH QUITE IMPRESSIVE 0-1 KM SHEAR/HELICITY VALUES.
WITH SFC DEW POINTS EXPECTED TO RISE/POOL INTO THE MID 60S JUST
AHEAD OF THE SFC FRONT....WILL NOT TAKE MUCH INSTABILITY TO SUPPORT
AT LEAST ISOLATED SEVERE WINDS AND POSSIBLY A COUPLE OF TORNADOES
WED NIGHT JUST AHEAD OF THE SFC FRONT AS IT APPROACHES. AT THIS
TIME...WOULD NOT BE AT ALL SURPRISED IF WE END UP WITH TOR WATCH
BOXES STACKED FROM WEST TO EAST ACROSS THE FORECAST AREA WED EVENING
INTO EARLY THU.
THEREAFTER...RAIN FREE CONDITIONS ARE EXPECTED FOR THE LATE
WEEK/WEEKEND TIME FRAME AS HIGH PRESSURE TAKES OVER. AFTER A BRIEF
CHILL BEHIND THE FRONT THU/THU NIGHT...SOUTHERLY WINDS SHOULD RETURN
IN THE FRI THRU SUN TIME FRAME...AND BRING US BACK INTO THE 60S AND
70S IN TIME FOR THE WEEKEND.
&&
.AVIATION...
ISSUED AT 548 PM CDT MON APR 8 2013
CURRENT SATELLITE TRENDS WOULD SUGGEST A MUCH MORE OPTIMISTIC
FORECAST. OPTED TO GO WITH VFR CONDITIONS THROUGHOUT TAF. THIS IS
BASED ON THE FACT THE MODELS HAVE BEEN ADVERTISING TOO MANY
CLOUDS/LOW CIGS WHERE THEY DONT EXIST. THUS HAVE WEIGHTED CURRENT
OBS AND SAT LOOP MUCH MORE THAN MODELS. WILL MONITOR CLOSELY FOR
CHANGES. OTHERWISE BRING BACK GUSTS AND VFR CIGS AFTER SUNRISE
TUESDAY. IF ANYTHING KEVV AND KOWB MAY BE CLOSER TO MVFR AFTER
SUNRISE TUESDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...RST
LONG TERM...GM
AVIATION...KH
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 PM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 1256 PM EDT SUN APR 7 2013
UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. HAVE DECREASED
RAIN CHANCES IN THE FAR NORTH AND INCREASED CLOUD COVER ACROSS THE
ENTIRE AREA. MINIMUM RELATIVE HUMIDITIES IN THE SOUTHEAST PART OF
FORECAST AREA HAVE REACHED 30 TO 35 PERCENT...BUT SHOULD NOT GO TOO
MUCH LOWER...WITH MINIMUMS 25 TO 30 PERCENT EXPECTED THIS AFTERNOON.
UPDATE ISSUED AT 1027 AM EDT SUN APR 7 2013
TEMPERATURE RISE THIS MORNING HAS BEEN QUICKER THAN FORECAST...BUT AT
THE SAME TIME CLOUDS ARE ALSO INCREASING QUICKER. HAVE ADJUSTED THE
HOURLY TEMPERATURE FORECAST AND SKY COVER FORECAST TO ACCOUNT FOR
THIS. INCREASING CLOUDS SHOULD KEEP CURRENT MAXIMUM TEMPERATURE
FORECAST ON TARGET.
ANOTHER ITEM TO ADDRESS FOR THIS UPDATE ARE DEWPOINTS AND POTENTIAL
FIRE WEATHER CONCERNS. DEWPOINTS HAVE BEEN RESPONDING TO INCREASING
SOUTHWEST FLOW...AND DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO
40 PERCENT RANGE...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE CRITICAL
THRESHOLDS. THIS WILL BE MONITORED CLOSELY THOUGH AS WINDS ARE MUCH
STRONGER THAN YESTERDAY. PLAN TO ISSUE AN SPS FOR ENHANCED WILD FIRE
THREAT.
FINALLY HAVE MADE SOME ADJUSTMENTS TO SHOWER CHANCES THIS AFTERNOON.
LATEST HRRR POINTS TOWARDS DELAYING THE ONSET OF RAIN CHANCES AND
ALSO EXTENDING THE CHANCE FURTHER SOUTH. HOWEVER THEN HRRR IS
OVERPLAYING PRECIPITATION CHANCES THIS MORNING. HAVE FOLLOWED THE
IDEA OF DELAYING PRECIPITATION CHANCES...BUT DID NOT EXTEND THE
CHANCE FURTHER SOUTH. HAVE ACTUALLY LOWERED THE PROBABILITY FROM
LIKELY TO CHANCE IN THE NORTH AS WELL.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 658 AM EDT SUN APR 7 2013
FRONTAL BOUNDARY IS JUST ABOUT TO THE CINCINNATI METRO AREA WITH THE
LINE OF SHOWERS PRETTY MUCH NON-EXISTENT AT THE TIME. HRRR IS ALSO
DOWNPLAYING ACTIVITY ALONG THIS BOUNDARY THROUGH THE MORNING HOURS
WHICH SEEMS VERY REASONABLE. STILL LOOKS LIKE WE COULD SEE AN UPTICK
IN SHOWER OR THUNDERSTORM ACTIVITY THIS AFTERNOON AS INSTABILITY
INCREASES JUST AHEAD OF THE STALLING BOUNDARY. MOST OF THE ACTIVITY
MAY BE TIED TO WHETHER OR NOT WE CAN GET ENOUGH INSTABILITY. GIVEN
DEWPOINTS MUCH LOWER THAN PREVIOUSLY ANTICIPATED...THIS COULD BE IN
JEOPARDY. HOWEVER...WILL MAINTAIN THE CURRENT POPS AND LET DAYSHIFT
RE-EVALUATE IF WE WILL SEE ANY SHOWER ACTIVITY IN THE FAR NORTH
TODAY. DEWPOINTS ARE FINALLY STARTING TO CREEP UP A BIT...BUT REMAIN
MUCH SLOWER THAN MODEL GUIDANCE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
FAIRLY QUIET WEATHER EARLY THIS SUNDAY MORNING. A VIGOROUS SHORTWAVE
IS PUSHING EAST ACROSS MICHIGAN THIS MORNING WITH A WEAK SURFACE
BOUNDARY BEING DRAGGED ACROSS THE OHIO RIVER VALLEY. AT THE
MOMENT...NOT MUCH ACTIVITY OUTSIDE OF A NARROW LINE OF BROKEN SHOWERS
PUSHING EAST ACROSS NORTHERN INDIANA...BACK INTO SOUTHERN ILLINOIS.
HRRR SEEMS TO HAVE A DECENT HANDLE ON THE RADAR TRENDS THIS MORNING.
THE SHORTWAVE WILL EXIT TO THE EAST TODAY...WITH THE FRONTAL BOUNDARY
STALLING ACROSS NORTHERN WEST VIRGINIA AND NORTHERN KENTUCKY. MODELS
SEEM TO BE IN VERY GOOD AGREEMENT ON THIS PLACEMENT. THE BEST CHANCES
FOR ANY RAIN WITH THIS FRONT WILL RESIDE ALONG THIS BOUNDARY...AND
WILL LIKELY REMAIN ALONG AND NORTH OF I-64. MEANWHILE...DRY
CONDITIONS WILL LIKELY PERSIST ACROSS THE REST OF EASTERN KENTUCKY.
WITH MOISTURE RECOVERY VERY POOR AT BEST OVERNIGHT AND THE PROSPECTS
OF DECENT MIXING TODAY...HAVE GONE WELL BELOW GUIDANCE WITH DEWPOINTS
YET AGAIN TODAY. IN FACT...A FEW PLACES...ESPECIALLY IN SOUTHEAST
KENTUCKY COULD SEE AFTERNOON RELATIVE HUMIDITIES FALL TO UNDER 30
PERCENT. WITH STRONGER SOUTHWEST WINDS TODAY...AHEAD OF THE FRONTAL
BOUNDARY...THIS COULD CREATE A PERIOD OF DANGEROUS FIRE WEATHER
CONDITIONS. THIS THREAT WILL HIGHLIGHTED IN THE HWO AND FIRE WEATHER
PLANNING FORECAST. HIGHS TODAY WILL CLIMB EVEN HIGHER INTO THE LOW TO
MID 70S...EXCEPT IN THE NORTH...WHERE CLOUDS AND PERHAPS
PRECIPITATION MAY KEEP LOCATIONS IN THE 60S.
FRONTAL BOUNDARY WILL SLOWLY DRIFT BACK TO THE NORTH THIS
EVENING...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH. SKIES
SHOULD REMAIN MOSTLY TO PARTLY CLEAR OVERNIGHT...ALLOWING SOME VALLEY
LOCATIONS TO DECOUPLE AND FALL BACK INTO THE 40S...WHILE RIDGES STAY
IN THE 50S. ANOTHER VIGOROUS SHORTWAVE WILL TRACK NORTHEAST THROUGH
THE PLAINS ON MONDAY...FURTHER PUSHING THE BOUNDARY TO THE NORTH AND
KEEPING EASTERN KENTUCKY DOMINATED BY STRONG RIDGING. A VERY WARM DAY
IS ON TAP WITH HIGHS SURGING WELL INTO THE 70S AREAWIDE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
MODELS CONTINUE TO SHOW GENERAL AGREEMENT EARLY IN THE PERIOD IN
TERMS OF HOW SYSTEMS WILL AFFECT OUR LOCAL WEATHER. PATTERN
AMPLIFICATION WILL BE ONGOING...WITH A WESTERN CONUS UPPER TROUGH
AND AND A SOUTHEAST CONUS UPPER RIDGE. STRONG SURFACE LOW PRESSURE
WILL TRACK FROM CO AT THE START OF THE PERIOD TO THE VICINITY OF
IL/IN BY THURSDAY MORNING. A FRONTAL BOUNDARY EXTENDING EAST FROM
THE LOW WILL BE LAID OUT NORTH OF THE OHIO RIVER. MODELS DISAGREE ON
EXACTLY HOW FAR NORTH/SOUTH IT WILL BE POSITIONED. THE ECMWF MANAGES
TO BRING IT FURTHER SOUTH THAN ANY OTHER MODEL...MAKING IT INTO THE
NORTHERN PART OF THE JKL FORECAST AREA BY 12Z THURSDAY. WITH ALL
OTHER GUIDANCE SHOWING IT FURTHER NORTH...WILL GO WITH A FORECAST
THAT KEEPS OUR AREA IN THE WARM SECTOR. A BROAD ZONE OF WARM AIR
ADVECTION WILL BRING MOISTURE NORTH FROM THE GULF OF MEXICO AND LIFT
IT ACROSS THE FRONT. THE BEST CHANCE OF RAIN WITH THIS WILL BE WELL
TO OUR NORTH...BUT CAN NOT RULE OUT SOME SHOWERS MAKING IT INTO THE
NORTHERN PART OF THE AREA.
THE FORECAST BECOMES MORE PROBLEMATIC LATER IN THE WEEK DUE TO
CONTINUED DIFFERENCES IN MODEL TIMING OF THE SURFACE LOW AND ITS
TRAILING COLD FRONT. THE ECMWF IS THE SLOWEST...WITH LOCAL FROPA NOT
HAPPENING UNTIL FRIDAY AFTERNOON. THE END OF THE NAM RUN ON WED
MORNING LOOKS SIMILAR TO THE GFS...WHICH ENDS UP WITH FROPA DURING
THE DAY THURSDAY. THERE ARE SOME MEMBERS OF THE GFS ENSEMBLE WHICH
SHOW SIMILAR TIMING AS THE ECMWF...BUT THE GFS ENSEMBLE MEAN IS MORE
SUPPORTIVE OF THE OPERATIONAL GFS. WILL FAVOR A COMPROMISE SOLUTION
CLOSER TO THE GFS. WITH THAT SAID...HIGHEST POPS...IN LIKELY
CATEGORY...WILL BE ON THURSDAY AND THURSDAY NIGHT. WILL USE HIGH
CHANCE ON FRIDAY TO LEND SOME CREDENCE TO THE ECMWF. ALL MODELS SHOW
INSTABILITY AHEAD OF THE COLD FRONT...AND A CHANCE OF THUNDER WILL
BE USED WITH THE APPROACH AND PASSAGE OF THE COLD FRONT. WINDS ALOFT
LOOK TO BE QUITE STRONG...AND WOULD SUPPORT SEVERE WX. HOWEVER...THE
DEGREE OF INSTABILITY DOES NOT REALLY STAND OUT. THE SET-UP WILL
NEED TO CONTINUE TO BE WATCHED.
THE WARMEST AIR MASS OF THE SEASON SO FAR WILL BE IN PLACE UP UNTIL
COLD FROPA. NEEDLESS TO SAY...FRONTAL TIMING WILL PLAY A KEY ROLE IN
TEMPS LATE IN THE PERIOD...AND LEADS TO A LOWER CONFIDENCE IN THE
TEMPERATURE FORECAST FOR THURSDAY INTO FRIDAY...AND A POTENTIAL FOR
MORE SIZEABLE ERRORS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN APR 7 2013
A COLD FRONT CONTINUES TO SLOWLY SAG SOUTH ACROSS OH AND INDIANA.
CLOUDS HAVE INCREASED AHEAD OF THE FRONT ACROSS KY...BUT CEILINGS ARE
EXPECTED TO REAMIN VFR THROUGH MONDAY. ISOLATED THUNDERSTORMS ARE STILL
POSSIBLE ACROSS FAR NORTHERN KY THIS AFTERNOON...BUT IF ANY OCCUR
THEY WILL BE WELL NORTH OF THE TAF SITES. GUSTY SOUTHWEST WINDS THIS
AFTERNOON WILL DIMINISH THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 1051 AM EDT SUN APR 7 2013
DEWPOINTS HAVE BEEN RISING IN THE INCREASING SOUTHWEST FLOW...AND
DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO 40 PERCENT
RANGE OVER SOUTHEAST KY...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE
CRITICAL THRESHOLDS. HOWEVER SOME SPOTS WILL BE NEAR 25 PERCENT RH
THIS AFTERNOON. THIS WILL BE MONITORED CLOSELY AS WINDS ARE MUCH
STRONGER THAN YESTERDAY...WITH GUSTS TO 30 MPH EXPECTED FOR THIS
AFTERNOON. HAVE ISSUED AN SPS FOR ENHANCED WILD FIRE THREAT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...SBH
FIRE WEATHER...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1257 PM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 1256 PM EDT SUN APR 7 2013
UPDATED NDFD AND ZFP FOR LATEST OBSERVATIONAL TRENDS. HAVE DECREASED
RAIN CHANCES IN THE FAR NORTH AND INCREASED CLOUD COVER ACROSS THE
ENTIRE AREA. MINIMUM RELATIVE HUMIDITIES IN THE SOUTHEAST PART OF
FORECAST AREA HAVE REACHED 30 TO 35 PERCENT...BUT SHOULD NOT GO TOO
MUCH LOWER...WITH MINIMUMS 25 TO 30 PERCENT EXPECTED THIS AFTERNOON.
UPDATE ISSUED AT 1027 AM EDT SUN APR 7 2013
TEMPERATURE RISE THIS MORNING HAS BEEN QUICKER THAN FORECAST...BUT AT
THE SAME TIME CLOUDS ARE ALSO INCREASING QUICKER. HAVE ADJUSTED THE
HOURLY TEMPERATURE FORECAST AND SKY COVER FORECAST TO ACCOUNT FOR
THIS. INCREASING CLOUDS SHOULD KEEP CURRENT MAXIMUM TEMPERATURE
FORECAST ON TARGET.
ANOTHER ITEM TO ADDRESS FOR THIS UPDATE ARE DEWPOINTS AND POTENTIAL
FIRE WEATHER CONCERNS. DEWPOINTS HAVE BEEN RESPONDING TO INCREASING
SOUTHWEST FLOW...AND DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO
40 PERCENT RANGE...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE CRITICAL
THRESHOLDS. THIS WILL BE MONITORED CLOSELY THOUGH AS WINDS ARE MUCH
STRONGER THAN YESTERDAY. PLAN TO ISSUE AN SPS FOR ENHANCED WILD FIRE
THREAT.
FINALLY HAVE MADE SOME ADJUSTMENTS TO SHOWER CHANCES THIS AFTERNOON.
LATEST HRRR POINTS TOWARDS DELAYING THE ONSET OF RAIN CHANCES AND
ALSO EXTENDING THE CHANCE FURTHER SOUTH. HOWEVER THEN HRRR IS
OVERPLAYING PRECIPITATION CHANCES THIS MORNING. HAVE FOLLOWED THE
IDEA OF DELAYING PRECIPITATION CHANCES...BUT DID NOT EXTEND THE
CHANCE FURTHER SOUTH. HAVE ACTUALLY LOWERED THE PROBABILITY FROM
LIKELY TO CHANCE IN THE NORTH AS WELL.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 658 AM EDT SUN APR 7 2013
FRONTAL BOUNDARY IS JUST ABOUT TO THE CINCINNATI METRO AREA WITH THE
LINE OF SHOWERS PRETTY MUCH NON-EXISTENT AT THE TIME. HRRR IS ALSO
DOWNPLAYING ACTIVITY ALONG THIS BOUNDARY THROUGH THE MORNING HOURS
WHICH SEEMS VERY REASONABLE. STILL LOOKS LIKE WE COULD SEE AN UPTICK
IN SHOWER OR THUNDERSTORM ACTIVITY THIS AFTERNOON AS INSTABILITY
INCREASES JUST AHEAD OF THE STALLING BOUNDARY. MOST OF THE ACTIVITY
MAY BE TIED TO WHETHER OR NOT WE CAN GET ENOUGH INSTABILITY. GIVEN
DEWPOINTS MUCH LOWER THAN PREVIOUSLY ANTICIPATED...THIS COULD BE IN
JEOPARDY. HOWEVER...WILL MAINTAIN THE CURRENT POPS AND LET DAYSHIFT
RE-EVALUATE IF WE WILL SEE ANY SHOWER ACTIVITY IN THE FAR NORTH
TODAY. DEWPOINTS ARE FINALLY STARTING TO CREEP UP A BIT...BUT REMAIN
MUCH SLOWER THAN MODEL GUIDANCE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
FAIRLY QUIET WEATHER EARLY THIS SUNDAY MORNING. A VIGOROUS SHORTWAVE
IS PUSHING EAST ACROSS MICHIGAN THIS MORNING WITH A WEAK SURFACE
BOUNDARY BEING DRAGGED ACROSS THE OHIO RIVER VALLEY. AT THE
MOMENT...NOT MUCH ACTIVITY OUTSIDE OF A NARROW LINE OF BROKEN SHOWERS
PUSHING EAST ACROSS NORTHERN INDIANA...BACK INTO SOUTHERN ILLINOIS.
HRRR SEEMS TO HAVE A DECENT HANDLE ON THE RADAR TRENDS THIS MORNING.
THE SHORTWAVE WILL EXIT TO THE EAST TODAY...WITH THE FRONTAL BOUNDARY
STALLING ACROSS NORTHERN WEST VIRGINIA AND NORTHERN KENTUCKY. MODELS
SEEM TO BE IN VERY GOOD AGREEMENT ON THIS PLACEMENT. THE BEST CHANCES
FOR ANY RAIN WITH THIS FRONT WILL RESIDE ALONG THIS BOUNDARY...AND
WILL LIKELY REMAIN ALONG AND NORTH OF I-64. MEANWHILE...DRY
CONDITIONS WILL LIKELY PERSIST ACROSS THE REST OF EASTERN KENTUCKY.
WITH MOISTURE RECOVERY VERY POOR AT BEST OVERNIGHT AND THE PROSPECTS
OF DECENT MIXING TODAY...HAVE GONE WELL BELOW GUIDANCE WITH DEWPOINTS
YET AGAIN TODAY. IN FACT...A FEW PLACES...ESPECIALLY IN SOUTHEAST
KENTUCKY COULD SEE AFTERNOON RELATIVE HUMIDITIES FALL TO UNDER 30
PERCENT. WITH STRONGER SOUTHWEST WINDS TODAY...AHEAD OF THE FRONTAL
BOUNDARY...THIS COULD CREATE A PERIOD OF DANGEROUS FIRE WEATHER
CONDITIONS. THIS THREAT WILL HIGHLIGHTED IN THE HWO AND FIRE WEATHER
PLANNING FORECAST. HIGHS TODAY WILL CLIMB EVEN HIGHER INTO THE LOW TO
MID 70S...EXCEPT IN THE NORTH...WHERE CLOUDS AND PERHAPS
PRECIPITATION MAY KEEP LOCATIONS IN THE 60S.
FRONTAL BOUNDARY WILL SLOWLY DRIFT BACK TO THE NORTH THIS
EVENING...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH. SKIES
SHOULD REMAIN MOSTLY TO PARTLY CLEAR OVERNIGHT...ALLOWING SOME VALLEY
LOCATIONS TO DECOUPLE AND FALL BACK INTO THE 40S...WHILE RIDGES STAY
IN THE 50S. ANOTHER VIGOROUS SHORTWAVE WILL TRACK NORTHEAST THROUGH
THE PLAINS ON MONDAY...FURTHER PUSHING THE BOUNDARY TO THE NORTH AND
KEEPING EASTERN KENTUCKY DOMINATED BY STRONG RIDGING. A VERY WARM DAY
IS ON TAP WITH HIGHS SURGING WELL INTO THE 70S AREAWIDE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
MODELS CONTINUE TO SHOW GENERAL AGREEMENT EARLY IN THE PERIOD IN
TERMS OF HOW SYSTEMS WILL AFFECT OUR LOCAL WEATHER. PATTERN
AMPLIFICATION WILL BE ONGOING...WITH A WESTERN CONUS UPPER TROUGH
AND AND A SOUTHEAST CONUS UPPER RIDGE. STRONG SURFACE LOW PRESSURE
WILL TRACK FROM CO AT THE START OF THE PERIOD TO THE VICINITY OF
IL/IN BY THURSDAY MORNING. A FRONTAL BOUNDARY EXTENDING EAST FROM
THE LOW WILL BE LAID OUT NORTH OF THE OHIO RIVER. MODELS DISAGREE ON
EXACTLY HOW FAR NORTH/SOUTH IT WILL BE POSITIONED. THE ECMWF MANAGES
TO BRING IT FURTHER SOUTH THAN ANY OTHER MODEL...MAKING IT INTO THE
NORTHERN PART OF THE JKL FORECAST AREA BY 12Z THURSDAY. WITH ALL
OTHER GUIDANCE SHOWING IT FURTHER NORTH...WILL GO WITH A FORECAST
THAT KEEPS OUR AREA IN THE WARM SECTOR. A BROAD ZONE OF WARM AIR
ADVECTION WILL BRING MOISTURE NORTH FROM THE GULF OF MEXICO AND LIFT
IT ACROSS THE FRONT. THE BEST CHANCE OF RAIN WITH THIS WILL BE WELL
TO OUR NORTH...BUT CAN NOT RULE OUT SOME SHOWERS MAKING IT INTO THE
NORTHERN PART OF THE AREA.
THE FORECAST BECOMES MORE PROBLEMATIC LATER IN THE WEEK DUE TO
CONTINUED DIFFERENCES IN MODEL TIMING OF THE SURFACE LOW AND ITS
TRAILING COLD FRONT. THE ECMWF IS THE SLOWEST...WITH LOCAL FROPA NOT
HAPPENING UNTIL FRIDAY AFTERNOON. THE END OF THE NAM RUN ON WED
MORNING LOOKS SIMILAR TO THE GFS...WHICH ENDS UP WITH FROPA DURING
THE DAY THURSDAY. THERE ARE SOME MEMBERS OF THE GFS ENSEMBLE WHICH
SHOW SIMILAR TIMING AS THE ECMWF...BUT THE GFS ENSEMBLE MEAN IS MORE
SUPPORTIVE OF THE OPERATIONAL GFS. WILL FAVOR A COMPROMISE SOLUTION
CLOSER TO THE GFS. WITH THAT SAID...HIGHEST POPS...IN LIKELY
CATEGORY...WILL BE ON THURSDAY AND THURSDAY NIGHT. WILL USE HIGH
CHANCE ON FRIDAY TO LEND SOME CREDENCE TO THE ECMWF. ALL MODELS SHOW
INSTABILITY AHEAD OF THE COLD FRONT...AND A CHANCE OF THUNDER WILL
BE USED WITH THE APPROACH AND PASSAGE OF THE COLD FRONT. WINDS ALOFT
LOOK TO BE QUITE STRONG...AND WOULD SUPPORT SEVERE WX. HOWEVER...THE
DEGREE OF INSTABILITY DOES NOT REALLY STAND OUT. THE SET-UP WILL
NEED TO CONTINUE TO BE WATCHED.
THE WARMEST AIR MASS OF THE SEASON SO FAR WILL BE IN PLACE UP UNTIL
COLD FROPA. NEEDLESS TO SAY...FRONTAL TIMING WILL PLAY A KEY ROLE IN
TEMPS LATE IN THE PERIOD...AND LEADS TO A LOWER CONFIDENCE IN THE
TEMPERATURE FORECAST FOR THURSDAY INTO FRIDAY...AND A POTENTIAL FOR
MORE SIZEABLE ERRORS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 658 AM EDT SUN APR 7 2013
VFR CONDITIONS WILL HOLD ON THROUGH THE PERIOD. AN APPROACHING COLD
FRONT WILL MOVE INTO NORTHERN KENTUCKY TODAY. SOME SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ARE POSSIBLE...MAINLY NORTH OF I-64. LOWER
CLOUDS AND PRECIPITATION WILL NOT LIKELY MAKE IT SOUTH OF
I-64...KEEPING THE TAF SITES DRY WITH JUST SOME HIGH CLOUDS TO
CONTEND WITH.
&&
.FIRE WEATHER...
ISSUED AT 1051 AM EDT SUN APR 7 2013
DEWPOINTS HAVE BEEN RISING IN THE INCREASING SOUTHWEST FLOW...AND
DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO 40 PERCENT
RANGE OVER SOUTHEAST KY...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE
CRITICAL THRESHOLDS. HOWEVER SOME SPOTS WILL BE NEAR 25 PERCENT RH
THIS AFTERNOON. THIS WILL BE MONITORED CLOSELY AS WINDS ARE MUCH
STRONGER THAN YESTERDAY...WITH GUSTS TO 30 MPH EXPECTED FOR THIS
AFTERNOON. HAVE ISSUED AN SPS FOR ENHANCED WILD FIRE THREAT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
FIRE WEATHER...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1052 AM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 1027 AM EDT SUN APR 7 2013
TEMPERATURE RISE THIS MORNING HAS BEEN QUICKER THAN FORECAST...BUT AT
THE SAME TIME CLOUDS ARE ALSO INCREASING QUICKER. HAVE ADJUSTED THE
HOURLY TEMPERATURE FORECAST AND SKY COVER FORECAST TO ACCOUNT FOR
THIS. INCREASING CLOUDS SHOULD KEEP CURRENT MAXIMUM TEMPERATURE
FORECAST ON TARGET.
ANOTHER ITEM TO ADDRESS FOR THIS UPDATE ARE DEWPOINTS AND POTENTIAL
FIRE WEATHER CONCERNS. DEWPOINTS HAVE BEEN RESPONDING TO INCREASING
SOUTHWEST FLOW...AND DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO
40 PERCENT RANGE...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE CRITICAL
THRESHOLDS. THIS WILL BE MONITORED CLOSELY THOUGH AS WINDS ARE MUCH
STRONGER THAN YESTERDAY. PLAN TO ISSUE AN SPS FOR ENHANCED WILD FIRE
THREAT.
FINALLY HAVE MADE SOME ADJUSTMENTS TO SHOWER CHANCES THIS AFTERNOON.
LATEST HRRR POINTS TOWARDS DELAYING THE ONSET OF RAIN CHANCES AND
ALSO EXTENDING THE CHANCE FURTHER SOUTH. HOWEVER THEN HRRR IS
OVERPLAYING PRECIPITATION CHANCES THIS MORNING. HAVE FOLLOWED THE
IDEA OF DELAYING PRECIPITATION CHANCES...BUT DID NOT EXTEND THE
CHANCE FURTHER SOUTH. HAVE ACTUALLY LOWERED THE PROBABILITY FROM
LIKELY TO CHANCE IN THE NORTH AS WELL.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 658 AM EDT SUN APR 7 2013
FRONTAL BOUNDARY IS JUST ABOUT TO THE CINCINNATI METRO AREA WITH THE
LINE OF SHOWERS PRETTY MUCH NON-EXISTENT AT THE TIME. HRRR IS ALSO
DOWNPLAYING ACTIVITY ALONG THIS BOUNDARY THROUGH THE MORNING HOURS
WHICH SEEMS VERY REASONABLE. STILL LOOKS LIKE WE COULD SEE AN UPTICK
IN SHOWER OR THUNDERSTORM ACTIVITY THIS AFTERNOON AS INSTABILITY
INCREASES JUST AHEAD OF THE STALLING BOUNDARY. MOST OF THE ACTIVITY
MAY BE TIED TO WHETHER OR NOT WE CAN GET ENOUGH INSTABILITY. GIVEN
DEWPOINTS MUCH LOWER THAN PREVIOUSLY ANTICIPATED...THIS COULD BE IN
JEOPARDY. HOWEVER...WILL MAINTAIN THE CURRENT POPS AND LET DAYSHIFT
RE-EVALUATE IF WE WILL SEE ANY SHOWER ACTIVITY IN THE FAR NORTH
TODAY. DEWPOINTS ARE FINALLY STARTING TO CREEP UP A BIT...BUT REMAIN
MUCH SLOWER THAN MODEL GUIDANCE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
FAIRLY QUIET WEATHER EARLY THIS SUNDAY MORNING. A VIGOROUS SHORTWAVE
IS PUSHING EAST ACROSS MICHIGAN THIS MORNING WITH A WEAK SURFACE
BOUNDARY BEING DRAGGED ACROSS THE OHIO RIVER VALLEY. AT THE
MOMENT...NOT MUCH ACTIVITY OUTSIDE OF A NARROW LINE OF BROKEN SHOWERS
PUSHING EAST ACROSS NORTHERN INDIANA...BACK INTO SOUTHERN ILLINOIS.
HRRR SEEMS TO HAVE A DECENT HANDLE ON THE RADAR TRENDS THIS MORNING.
THE SHORTWAVE WILL EXIT TO THE EAST TODAY...WITH THE FRONTAL BOUNDARY
STALLING ACROSS NORTHERN WEST VIRGINIA AND NORTHERN KENTUCKY. MODELS
SEEM TO BE IN VERY GOOD AGREEMENT ON THIS PLACEMENT. THE BEST CHANCES
FOR ANY RAIN WITH THIS FRONT WILL RESIDE ALONG THIS BOUNDARY...AND
WILL LIKELY REMAIN ALONG AND NORTH OF I-64. MEANWHILE...DRY
CONDITIONS WILL LIKELY PERSIST ACROSS THE REST OF EASTERN KENTUCKY.
WITH MOISTURE RECOVERY VERY POOR AT BEST OVERNIGHT AND THE PROSPECTS
OF DECENT MIXING TODAY...HAVE GONE WELL BELOW GUIDANCE WITH DEWPOINTS
YET AGAIN TODAY. IN FACT...A FEW PLACES...ESPECIALLY IN SOUTHEAST
KENTUCKY COULD SEE AFTERNOON RELATIVE HUMIDITIES FALL TO UNDER 30
PERCENT. WITH STRONGER SOUTHWEST WINDS TODAY...AHEAD OF THE FRONTAL
BOUNDARY...THIS COULD CREATE A PERIOD OF DANGEROUS FIRE WEATHER
CONDITIONS. THIS THREAT WILL HIGHLIGHTED IN THE HWO AND FIRE WEATHER
PLANNING FORECAST. HIGHS TODAY WILL CLIMB EVEN HIGHER INTO THE LOW TO
MID 70S...EXCEPT IN THE NORTH...WHERE CLOUDS AND PERHAPS
PRECIPITATION MAY KEEP LOCATIONS IN THE 60S.
FRONTAL BOUNDARY WILL SLOWLY DRIFT BACK TO THE NORTH THIS
EVENING...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH. SKIES
SHOULD REMAIN MOSTLY TO PARTLY CLEAR OVERNIGHT...ALLOWING SOME VALLEY
LOCATIONS TO DECOUPLE AND FALL BACK INTO THE 40S...WHILE RIDGES STAY
IN THE 50S. ANOTHER VIGOROUS SHORTWAVE WILL TRACK NORTHEAST THROUGH
THE PLAINS ON MONDAY...FURTHER PUSHING THE BOUNDARY TO THE NORTH AND
KEEPING EASTERN KENTUCKY DOMINATED BY STRONG RIDGING. A VERY WARM DAY
IS ON TAP WITH HIGHS SURGING WELL INTO THE 70S AREAWIDE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
MODELS CONTINUE TO SHOW GENERAL AGREEMENT EARLY IN THE PERIOD IN
TERMS OF HOW SYSTEMS WILL AFFECT OUR LOCAL WEATHER. PATTERN
AMPLIFICATION WILL BE ONGOING...WITH A WESTERN CONUS UPPER TROUGH
AND AND A SOUTHEAST CONUS UPPER RIDGE. STRONG SURFACE LOW PRESSURE
WILL TRACK FROM CO AT THE START OF THE PERIOD TO THE VICINITY OF
IL/IN BY THURSDAY MORNING. A FRONTAL BOUNDARY EXTENDING EAST FROM
THE LOW WILL BE LAID OUT NORTH OF THE OHIO RIVER. MODELS DISAGREE ON
EXACTLY HOW FAR NORTH/SOUTH IT WILL BE POSITIONED. THE ECMWF MANAGES
TO BRING IT FURTHER SOUTH THAN ANY OTHER MODEL...MAKING IT INTO THE
NORTHERN PART OF THE JKL FORECAST AREA BY 12Z THURSDAY. WITH ALL
OTHER GUIDANCE SHOWING IT FURTHER NORTH...WILL GO WITH A FORECAST
THAT KEEPS OUR AREA IN THE WARM SECTOR. A BROAD ZONE OF WARM AIR
ADVECTION WILL BRING MOISTURE NORTH FROM THE GULF OF MEXICO AND LIFT
IT ACROSS THE FRONT. THE BEST CHANCE OF RAIN WITH THIS WILL BE WELL
TO OUR NORTH...BUT CAN NOT RULE OUT SOME SHOWERS MAKING IT INTO THE
NORTHERN PART OF THE AREA.
THE FORECAST BECOMES MORE PROBLEMATIC LATER IN THE WEEK DUE TO
CONTINUED DIFFERENCES IN MODEL TIMING OF THE SURFACE LOW AND ITS
TRAILING COLD FRONT. THE ECMWF IS THE SLOWEST...WITH LOCAL FROPA NOT
HAPPENING UNTIL FRIDAY AFTERNOON. THE END OF THE NAM RUN ON WED
MORNING LOOKS SIMILAR TO THE GFS...WHICH ENDS UP WITH FROPA DURING
THE DAY THURSDAY. THERE ARE SOME MEMBERS OF THE GFS ENSEMBLE WHICH
SHOW SIMILAR TIMING AS THE ECMWF...BUT THE GFS ENSEMBLE MEAN IS MORE
SUPPORTIVE OF THE OPERATIONAL GFS. WILL FAVOR A COMPROMISE SOLUTION
CLOSER TO THE GFS. WITH THAT SAID...HIGHEST POPS...IN LIKELY
CATEGORY...WILL BE ON THURSDAY AND THURSDAY NIGHT. WILL USE HIGH
CHANCE ON FRIDAY TO LEND SOME CREDENCE TO THE ECMWF. ALL MODELS SHOW
INSTABILITY AHEAD OF THE COLD FRONT...AND A CHANCE OF THUNDER WILL
BE USED WITH THE APPROACH AND PASSAGE OF THE COLD FRONT. WINDS ALOFT
LOOK TO BE QUITE STRONG...AND WOULD SUPPORT SEVERE WX. HOWEVER...THE
DEGREE OF INSTABILITY DOES NOT REALLY STAND OUT. THE SET-UP WILL
NEED TO CONTINUE TO BE WATCHED.
THE WARMEST AIR MASS OF THE SEASON SO FAR WILL BE IN PLACE UP UNTIL
COLD FROPA. NEEDLESS TO SAY...FRONTAL TIMING WILL PLAY A KEY ROLE IN
TEMPS LATE IN THE PERIOD...AND LEADS TO A LOWER CONFIDENCE IN THE
TEMPERATURE FORECAST FOR THURSDAY INTO FRIDAY...AND A POTENTIAL FOR
MORE SIZEABLE ERRORS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 658 AM EDT SUN APR 7 2013
VFR CONDITIONS WILL HOLD ON THROUGH THE PERIOD. AN APPROACHING COLD
FRONT WILL MOVE INTO NORTHERN KENTUCKY TODAY. SOME SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ARE POSSIBLE...MAINLY NORTH OF I-64. LOWER
CLOUDS AND PRECIPITATION WILL NOT LIKELY MAKE IT SOUTH OF
I-64...KEEPING THE TAF SITES DRY WITH JUST SOME HIGH CLOUDS TO
CONTEND WITH.
&&
.FIRE WEATHER...
ISSUED AT 1051 AM EDT SUN APR 7 2013
DEWPOINTS HAVE BEEN RISING IN THE INCREASING SOUTHWEST FLOW...AND
DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO 40 PERCENT
RANGE OVER SOUTHEAST KY...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE
CRITICAL THRESHOLDS. HOWEVER SOME SPOTS WILL BE NEAR 25 PERCENT RH
THIS AFTERNOON. THIS WILL BE MONITORED CLOSELY AS WINDS ARE MUCH
STRONGER THAN YESTERDAY...WITH GUSTS TO 30 MPH EXPECTED FOR THIS
AFTERNOON. HAVE ISSUED AN SPS FOR ENHANCED WILD FIRE THREAT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
FIRE WEATHER...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1028 AM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 1027 AM EDT SUN APR 7 2013
TEMPERATURE RISE THIS MORNING HAS BEEN QUICKER THAN FORECAST...BUT AT
THE SAME TIME CLOUDS ARE ALSO INCREASING QUICKER. HAVE ADJUSTED THE
HOURLY TEMPERATURE FORECAST AND SKY COVER FORECAST TO ACCOUNT FOR
THIS. INCREASING CLOUDS SHOULD KEEP CURRENT MAXIMUM TEMPERATURE
FORECAST ON TARGET.
ANOTHER ITEM TO ADDRESS FOR THIS UPDATE ARE DEWPOINTS AND POTENTIAL
FIRE WEATHER CONCERNS. DEWPOINTS HAVE BEEN RESPONDING TO INCREASING
SOUTHWEST FLOW...AND DESPITE RELATIVE HUMIDITY CURRENTLY IN THE 30 TO
40 PERCENT RANGE...WE SHOULD SEE RELATIVE HUMIDITY STAY ABOVE CRITICAL
THRESHOLDS. THIS WILL BE MONITORED CLOSELY THOUGH AS WINDS ARE MUCH
STRONGER THAN YESTERDAY. PLAN TO ISSUE AN SPS FOR ENHANCED WILD FIRE
THREAT.
FINALLY HAVE MADE SOME ADJUSTMENTS TO SHOWER CHANCES THIS AFTERNOON.
LATEST HRRR POINTS TOWARDS DELAYING THE ONSET OF RAIN CHANCES AND
ALSO EXTENDING THE CHANCE FURTHER SOUTH. HOWEVER THEN HRRR IS
OVERPLAYING PRECIPITATION CHANCES THIS MORNING. HAVE FOLLOWED THE
IDEA OF DELAYING PRECIPITATION CHANCES...BUT DID NOT EXTEND THE
CHANCE FURTHER SOUTH. HAVE ACTUALLY LOWERED THE PROBABILITY FROM
LIKELY TO CHANCE IN THE NORTH AS WELL.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 658 AM EDT SUN APR 7 2013
FRONTAL BOUNDARY IS JUST ABOUT TO THE CINCINNATI METRO AREA WITH THE
LINE OF SHOWERS PRETTY MUCH NON-EXISTENT AT THE TIME. HRRR IS ALSO
DOWNPLAYING ACTIVITY ALONG THIS BOUNDARY THROUGH THE MORNING HOURS
WHICH SEEMS VERY REASONABLE. STILL LOOKS LIKE WE COULD SEE AN UPTICK
IN SHOWER OR THUNDERSTORM ACTIVITY THIS AFTERNOON AS INSTABILITY
INCREASES JUST AHEAD OF THE STALLING BOUNDARY. MOST OF THE ACTIVITY
MAY BE TIED TO WHETHER OR NOT WE CAN GET ENOUGH INSTABILITY. GIVEN
DEWPOINTS MUCH LOWER THAN PREVIOUSLY ANTICIPATED...THIS COULD BE IN
JEOPARDY. HOWEVER...WILL MAINTAIN THE CURRENT POPS AND LET DAYSHIFT
RE-EVALUATE IF WE WILL SEE ANY SHOWER ACTIVITY IN THE FAR NORTH
TODAY. DEWPOINTS ARE FINALLY STARTING TO CREEP UP A BIT...BUT REMAIN
MUCH SLOWER THAN MODEL GUIDANCE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
FAIRLY QUIET WEATHER EARLY THIS SUNDAY MORNING. A VIGOROUS SHORTWAVE
IS PUSHING EAST ACROSS MICHIGAN THIS MORNING WITH A WEAK SURFACE
BOUNDARY BEING DRAGGED ACROSS THE OHIO RIVER VALLEY. AT THE
MOMENT...NOT MUCH ACTIVITY OUTSIDE OF A NARROW LINE OF BROKEN SHOWERS
PUSHING EAST ACROSS NORTHERN INDIANA...BACK INTO SOUTHERN ILLINOIS.
HRRR SEEMS TO HAVE A DECENT HANDLE ON THE RADAR TRENDS THIS MORNING.
THE SHORTWAVE WILL EXIT TO THE EAST TODAY...WITH THE FRONTAL BOUNDARY
STALLING ACROSS NORTHERN WEST VIRGINIA AND NORTHERN KENTUCKY. MODELS
SEEM TO BE IN VERY GOOD AGREEMENT ON THIS PLACEMENT. THE BEST CHANCES
FOR ANY RAIN WITH THIS FRONT WILL RESIDE ALONG THIS BOUNDARY...AND
WILL LIKELY REMAIN ALONG AND NORTH OF I-64. MEANWHILE...DRY
CONDITIONS WILL LIKELY PERSIST ACROSS THE REST OF EASTERN KENTUCKY.
WITH MOISTURE RECOVERY VERY POOR AT BEST OVERNIGHT AND THE PROSPECTS
OF DECENT MIXING TODAY...HAVE GONE WELL BELOW GUIDANCE WITH DEWPOINTS
YET AGAIN TODAY. IN FACT...A FEW PLACES...ESPECIALLY IN SOUTHEAST
KENTUCKY COULD SEE AFTERNOON RELATIVE HUMIDITIES FALL TO UNDER 30
PERCENT. WITH STRONGER SOUTHWEST WINDS TODAY...AHEAD OF THE FRONTAL
BOUNDARY...THIS COULD CREATE A PERIOD OF DANGEROUS FIRE WEATHER
CONDITIONS. THIS THREAT WILL HIGHLIGHTED IN THE HWO AND FIRE WEATHER
PLANNING FORECAST. HIGHS TODAY WILL CLIMB EVEN HIGHER INTO THE LOW TO
MID 70S...EXCEPT IN THE NORTH...WHERE CLOUDS AND PERHAPS
PRECIPITATION MAY KEEP LOCATIONS IN THE 60S.
FRONTAL BOUNDARY WILL SLOWLY DRIFT BACK TO THE NORTH THIS
EVENING...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH. SKIES
SHOULD REMAIN MOSTLY TO PARTLY CLEAR OVERNIGHT...ALLOWING SOME VALLEY
LOCATIONS TO DECOUPLE AND FALL BACK INTO THE 40S...WHILE RIDGES STAY
IN THE 50S. ANOTHER VIGOROUS SHORTWAVE WILL TRACK NORTHEAST THROUGH
THE PLAINS ON MONDAY...FURTHER PUSHING THE BOUNDARY TO THE NORTH AND
KEEPING EASTERN KENTUCKY DOMINATED BY STRONG RIDGING. A VERY WARM DAY
IS ON TAP WITH HIGHS SURGING WELL INTO THE 70S AREAWIDE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
MODELS CONTINUE TO SHOW GENERAL AGREEMENT EARLY IN THE PERIOD IN
TERMS OF HOW SYSTEMS WILL AFFECT OUR LOCAL WEATHER. PATTERN
AMPLIFICATION WILL BE ONGOING...WITH A WESTERN CONUS UPPER TROUGH
AND AND A SOUTHEAST CONUS UPPER RIDGE. STRONG SURFACE LOW PRESSURE
WILL TRACK FROM CO AT THE START OF THE PERIOD TO THE VICINITY OF
IL/IN BY THURSDAY MORNING. A FRONTAL BOUNDARY EXTENDING EAST FROM
THE LOW WILL BE LAID OUT NORTH OF THE OHIO RIVER. MODELS DISAGREE ON
EXACTLY HOW FAR NORTH/SOUTH IT WILL BE POSITIONED. THE ECMWF MANAGES
TO BRING IT FURTHER SOUTH THAN ANY OTHER MODEL...MAKING IT INTO THE
NORTHERN PART OF THE JKL FORECAST AREA BY 12Z THURSDAY. WITH ALL
OTHER GUIDANCE SHOWING IT FURTHER NORTH...WILL GO WITH A FORECAST
THAT KEEPS OUR AREA IN THE WARM SECTOR. A BROAD ZONE OF WARM AIR
ADVECTION WILL BRING MOISTURE NORTH FROM THE GULF OF MEXICO AND LIFT
IT ACROSS THE FRONT. THE BEST CHANCE OF RAIN WITH THIS WILL BE WELL
TO OUR NORTH...BUT CAN NOT RULE OUT SOME SHOWERS MAKING IT INTO THE
NORTHERN PART OF THE AREA.
THE FORECAST BECOMES MORE PROBLEMATIC LATER IN THE WEEK DUE TO
CONTINUED DIFFERENCES IN MODEL TIMING OF THE SURFACE LOW AND ITS
TRAILING COLD FRONT. THE ECMWF IS THE SLOWEST...WITH LOCAL FROPA NOT
HAPPENING UNTIL FRIDAY AFTERNOON. THE END OF THE NAM RUN ON WED
MORNING LOOKS SIMILAR TO THE GFS...WHICH ENDS UP WITH FROPA DURING
THE DAY THURSDAY. THERE ARE SOME MEMBERS OF THE GFS ENSEMBLE WHICH
SHOW SIMILAR TIMING AS THE ECMWF...BUT THE GFS ENSEMBLE MEAN IS MORE
SUPPORTIVE OF THE OPERATIONAL GFS. WILL FAVOR A COMPROMISE SOLUTION
CLOSER TO THE GFS. WITH THAT SAID...HIGHEST POPS...IN LIKELY
CATEGORY...WILL BE ON THURSDAY AND THURSDAY NIGHT. WILL USE HIGH
CHANCE ON FRIDAY TO LEND SOME CREDENCE TO THE ECMWF. ALL MODELS SHOW
INSTABILITY AHEAD OF THE COLD FRONT...AND A CHANCE OF THUNDER WILL
BE USED WITH THE APPROACH AND PASSAGE OF THE COLD FRONT. WINDS ALOFT
LOOK TO BE QUITE STRONG...AND WOULD SUPPORT SEVERE WX. HOWEVER...THE
DEGREE OF INSTABILITY DOES NOT REALLY STAND OUT. THE SET-UP WILL
NEED TO CONTINUE TO BE WATCHED.
THE WARMEST AIR MASS OF THE SEASON SO FAR WILL BE IN PLACE UP UNTIL
COLD FROPA. NEEDLESS TO SAY...FRONTAL TIMING WILL PLAY A KEY ROLE IN
TEMPS LATE IN THE PERIOD...AND LEADS TO A LOWER CONFIDENCE IN THE
TEMPERATURE FORECAST FOR THURSDAY INTO FRIDAY...AND A POTENTIAL FOR
MORE SIZEABLE ERRORS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 658 AM EDT SUN APR 7 2013
VFR CONDITIONS WILL HOLD ON THROUGH THE PERIOD. AN APPROACHING COLD
FRONT WILL MOVE INTO NORTHERN KENTUCKY TODAY. SOME SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ARE POSSIBLE...MAINLY NORTH OF I-64. LOWER
CLOUDS AND PRECIPITATION WILL NOT LIKELY MAKE IT SOUTH OF
I-64...KEEPING THE TAF SITES DRY WITH JUST SOME HIGH CLOUDS TO
CONTEND WITH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
658 AM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 658 AM EDT SUN APR 7 2013
FRONTAL BOUNDARY IS JUST ABOUT TO THE CINCINNATI METRO AREA WITH THE
LINE OF SHOWERS PRETTY MUCH NON-EXISTENT AT THE TIME. HRRR IS ALSO
DOWNPLAYING ACTIVITY ALONG THIS BOUNDARY THROUGH THE MORNING HOURS
WHICH SEEMS VERY REASONABLE. STILL LOOKS LIKE WE COULD SEE AN UPTICK
IN SHOWER OR THUNDERSTORM ACTIVITY THIS AFTERNOON AS INSTABILITY
INCREASES JUST AHEAD OF THE STALLING BOUNDARY. MOST OF THE ACTIVITY
MAY BE TIED TO WHETHER OR NOT WE CAN GET ENOUGH INSTABILITY. GIVEN
DEWPOINTS MUCH LOWER THAN PREVIOUSLY ANTICIPATED...THIS COULD BE IN
JEOPARDY. HOWEVER...WILL MAINTAIN THE CURRENT POPS AND LET DAYSHIFT
RE-EVALUATE IF WE WILL SEE ANY SHOWER ACTIVITY IN THE FAR NORTH
TODAY. DEWPOINTS ARE FINALLY STARTING TO CREEP UP A BIT...BUT REMAIN
MUCH SLOWER THAN MODEL GUIDANCE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
FAIRLY QUIET WEATHER EARLY THIS SUNDAY MORNING. A VIGOROUS SHORTWAVE
IS PUSHING EAST ACROSS MICHIGAN THIS MORNING WITH A WEAK SURFACE
BOUNDARY BEING DRAGGED ACROSS THE OHIO RIVER VALLEY. AT THE
MOMENT...NOT MUCH ACTIVITY OUTSIDE OF A NARROW LINE OF BROKEN SHOWERS
PUSHING EAST ACROSS NORTHERN INDIANA...BACK INTO SOUTHERN ILLINOIS.
HRRR SEEMS TO HAVE A DECENT HANDLE ON THE RADAR TRENDS THIS MORNING.
THE SHORTWAVE WILL EXIT TO THE EAST TODAY...WITH THE FRONTAL BOUNDARY
STALLING ACROSS NORTHERN WEST VIRGINIA AND NORTHERN KENTUCKY. MODELS
SEEM TO BE IN VERY GOOD AGREEMENT ON THIS PLACEMENT. THE BEST CHANCES
FOR ANY RAIN WITH THIS FRONT WILL RESIDE ALONG THIS BOUNDARY...AND
WILL LIKELY REMAIN ALONG AND NORTH OF I-64. MEANWHILE...DRY
CONDITIONS WILL LIKELY PERSIST ACROSS THE REST OF EASTERN KENTUCKY.
WITH MOISTURE RECOVERY VERY POOR AT BEST OVERNIGHT AND THE PROSPECTS
OF DECENT MIXING TODAY...HAVE GONE WELL BELOW GUIDANCE WITH DEWPOINTS
YET AGAIN TODAY. IN FACT...A FEW PLACES...ESPECIALLY IN SOUTHEAST
KENTUCKY COULD SEE AFTERNOON RELATIVE HUMIDITIES FALL TO UNDER 30
PERCENT. WITH STRONGER SOUTHWEST WINDS TODAY...AHEAD OF THE FRONTAL
BOUNDARY...THIS COULD CREATE A PERIOD OF DANGEROUS FIRE WEATHER
CONDITIONS. THIS THREAT WILL HIGHLIGHTED IN THE HWO AND FIRE WEATHER
PLANNING FORECAST. HIGHS TODAY WILL CLIMB EVEN HIGHER INTO THE LOW TO
MID 70S...EXCEPT IN THE NORTH...WHERE CLOUDS AND PERHAPS
PRECIPITATION MAY KEEP LOCATIONS IN THE 60S.
FRONTAL BOUNDARY WILL SLOWLY DRIFT BACK TO THE NORTH THIS
EVENING...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH. SKIES
SHOULD REMAIN MOSTLY TO PARTLY CLEAR OVERNIGHT...ALLOWING SOME VALLEY
LOCATIONS TO DECOUPLE AND FALL BACK INTO THE 40S...WHILE RIDGES STAY
IN THE 50S. ANOTHER VIGOROUS SHORTWAVE WILL TRACK NORTHEAST THROUGH
THE PLAINS ON MONDAY...FURTHER PUSHING THE BOUNDARY TO THE NORTH AND
KEEPING EASTERN KENTUCKY DOMINATED BY STRONG RIDGING. A VERY WARM DAY
IS ON TAP WITH HIGHS SURGING WELL INTO THE 70S AREAWIDE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 AM EDT SUN APR 7 2013
MODELS CONTINUE TO SHOW GENERAL AGREEMENT EARLY IN THE PERIOD IN
TERMS OF HOW SYSTEMS WILL AFFECT OUR LOCAL WEATHER. PATTERN
AMPLIFICATION WILL BE ONGOING...WITH A WESTERN CONUS UPPER TROUGH
AND AND A SOUTHEAST CONUS UPPER RIDGE. STRONG SURFACE LOW PRESSURE
WILL TRACK FROM CO AT THE START OF THE PERIOD TO THE VICINITY OF
IL/IN BY THURSDAY MORNING. A FRONTAL BOUNDARY EXTENDING EAST FROM
THE LOW WILL BE LAID OUT NORTH OF THE OHIO RIVER. MODELS DISAGREE ON
EXACTLY HOW FAR NORTH/SOUTH IT WILL BE POSITIONED. THE ECMWF MANAGES
TO BRING IT FURTHER SOUTH THAN ANY OTHER MODEL...MAKING IT INTO THE
NORTHERN PART OF THE JKL FORECAST AREA BY 12Z THURSDAY. WITH ALL
OTHER GUIDANCE SHOWING IT FURTHER NORTH...WILL GO WITH A FORECAST
THAT KEEPS OUR AREA IN THE WARM SECTOR. A BROAD ZONE OF WARM AIR
ADVECTION WILL BRING MOISTURE NORTH FROM THE GULF OF MEXICO AND LIFT
IT ACROSS THE FRONT. THE BEST CHANCE OF RAIN WITH THIS WILL BE WELL
TO OUR NORTH...BUT CAN NOT RULE OUT SOME SHOWERS MAKING IT INTO THE
NORTHERN PART OF THE AREA.
THE FORECAST BECOMES MORE PROBLEMATIC LATER IN THE WEEK DUE TO
CONTINUED DIFFERENCES IN MODEL TIMING OF THE SURFACE LOW AND ITS
TRAILING COLD FRONT. THE ECMWF IS THE SLOWEST...WITH LOCAL FROPA NOT
HAPPENING UNTIL FRIDAY AFTERNOON. THE END OF THE NAM RUN ON WED
MORNING LOOKS SIMILAR TO THE GFS...WHICH ENDS UP WITH FROPA DURING
THE DAY THURSDAY. THERE ARE SOME MEMBERS OF THE GFS ENSEMBLE WHICH
SHOW SIMILAR TIMING AS THE ECMWF...BUT THE GFS ENSEMBLE MEAN IS MORE
SUPPORTIVE OF THE OPERATIONAL GFS. WILL FAVOR A COMPROMISE SOLUTION
CLOSER TO THE GFS. WITH THAT SAID...HIGHEST POPS...IN LIKELY
CATEGORY...WILL BE ON THURSDAY AND THURSDAY NIGHT. WILL USE HIGH
CHANCE ON FRIDAY TO LEND SOME CREDENCE TO THE ECMWF. ALL MODELS SHOW
INSTABILITY AHEAD OF THE COLD FRONT...AND A CHANCE OF THUNDER WILL
BE USED WITH THE APPROACH AND PASSAGE OF THE COLD FRONT. WINDS ALOFT
LOOK TO BE QUITE STRONG...AND WOULD SUPPORT SEVERE WX. HOWEVER...THE
DEGREE OF INSTABILITY DOES NOT REALLY STAND OUT. THE SET-UP WILL
NEED TO CONTINUE TO BE WATCHED.
THE WARMEST AIR MASS OF THE SEASON SO FAR WILL BE IN PLACE UP UNTIL
COLD FROPA. NEEDLESS TO SAY...FRONTAL TIMING WILL PLAY A KEY ROLE IN
TEMPS LATE IN THE PERIOD...AND LEADS TO A LOWER CONFIDENCE IN THE
TEMPERATURE FORECAST FOR THURSDAY INTO FRIDAY...AND A POTENTIAL FOR
MORE SIZEABLE ERRORS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 658 AM EDT SUN APR 7 2013
VFR CONDITIONS WILL HOLD ON THROUGH THE PERIOD. AN APPROACHING COLD
FRONT WILL MOVE INTO NORTHERN KENTUCKY TODAY. SOME SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ARE POSSIBLE...MAINLY NORTH OF I-64. LOWER
CLOUDS AND PRECIPITATION WILL NOT LIKELY MAKE IT SOUTH OF
I-64...KEEPING THE TAF SITES DRY WITH JUST SOME HIGH CLOUDS TO
CONTEND WITH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
130 AM EDT SUN APR 7 2013
.UPDATE...
ISSUED AT 130 AM EDT SUN APR 7 2013
LATEST HRRR SHOWS A MUCH SLOWER PROGRESSION OF THE FRONTAL BOUNDARY
TOWARDS OUR AREA TOMORROW AND PENETRATING MUCH LESS INTO THE AREA.
THUS...HAVE TRIMMED BACK POPS ACROSS EAST CENTRAL KENTUCKY. A LITTLE
CONCERNED EARLIER BY THE AMOUNT OF DRY AIR STILL PRESENT ACROSS
EASTERN KENTUCKY WITH DEWPOINTS STILL HOLDING IN THE LOWER TO MIDDLE
30S IN MANY LOCATIONS. HAVE GONE AHEAD AND LOWERED DEWPOINTS THROUGH
THE DAY TODAY...ESPECIALLY ACROSS THE SOUTHEAST. MODELS APPEAR TO BE
TOO AGGRESSIVE WITH THE MOISTURE RECOVERY ONCE AGAIN.
FORTUNATELY...EVEN USING A WORST CASE SCENARIO...I CANNOT GET
RELATIVE HUMIDITIES TO FALL UNDER 25 PERCENT...SO THAT PUTS RED FLAG
CRITERIA OUT OF THE PICTURE. HOWEVER...STILL GOING TO SEE THE
POTENTIAL FOR DANGEROUS FIRE WEATHER CONDITIONS TODAY WITH MUCH
GUSTIER SOUTHWEST WINDS DEVELOPING BY MID MORNING. PLAN TO HIGHLIGHT
THIS FIRE DANGER IN THE FIRE WEATHER PLANNING FORECAST AND IN THE
HWO.
UPDATE ISSUED AT 1042 PM EDT SAT APR 6 2013
MADE A FEW ADJUSTMENTS TO THE LOW TEMPERATURES TONIGHT. THE FAR
EASTERN SHELTERED VALLEYS ARE ON THEIR WAY DOWN...WITH A FEW SPOTS
ALREADY DIPPING TO BELOW 50 DEGREES. AT THIS PACE...A FEW UPPER 30S
STILL LOOK ACHIEVABLE. FURTHER WEST...TEMPERATURES HAVE BEEN SLOW TO
COOL OFF WITH PERSISTENT HIGH CLOUDS THROUGH EARLY THIS EVENING AS
WELL SOUTH TO SOUTH SOUTHEAST WINDS AT AROUND 5 KTS. THERE WILL BE A
DECENT CLEAR SLOT FOR SEVERAL HOURS...SO A DROP OFF STILL LOOKS
GOOD...HOWEVER DID TWEAK UP SOME OF THE LOWS IN THE WESTERN HALF OF
THE AREA GIVEN THE SLOW START.
UPDATE ISSUED AT 705 PM EDT SAT APR 6 2013
AN AREA OF THICKER HIGH CLOUDS IS CURRENTLY MOVING EAST ACROSS THE
AREA. THE BACK EDGE OF THESE THICKER CLOUDS WILL EXIT THE FAR EAST
BEFORE MIDNIGHT BASED ON THE LATEST SATELLITE TRENDS. WILL THEREFORE
MENTION MOSTLY CLOUDY WORDING EARLY ON FOR SOME LOCATIONS.
CONSEQUENTLY...WILL TWEAK THE DIURNAL DROP OFF...HOWEVER WILL STICK
WITH THE FORECAST LOWS FOR NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 302 PM EDT SAT APR 6 2013
HIGH THIN CLOUDS WILL STREAM INTO THE AREA TONIGHT...BUT THIS SHOULD
NOT PREVENT ANOTHER FAIRLY SIGNIFICANT RIDGE VALLEY TEMPERATURE SPLIT
SETTING UP. THIS WILL BE DEPICTED IN THE FORECAST GRIDS WITH CLOSE
TO A 10 DEGREE SPREAD IN SOME AREAS...ESPECIALLY IN THE EAST. A COLD
FRONT WILL DROP SOUTH INTO OHIO AND INDIANA ON SUNDAY. THE 12Z NAM
AND GFS HAVE TRENDED TOWARDS THE PRECIPITATION CHANCES EXTENDING A
LITTLE FURTHER SOUTH...AND THIS IS REFLECTED IN THEIR CORRESPONDING
MOS GUIDANCE AS WELL. THIS IDEA IS ALSO SUPPORTED BY THE 09Z SREF BUT
NOT BY THE 12Z GEM OR 00Z ECMWF. IT STILL APPEARS THERE WILL BE A
FAIRLY STRONG GRADIENT OF PRECIPITATION CHANCES ON SUNDAY...AND WILL
CARRY AROUND 10 PERCENT IN THE FAR SOUTHEAST TO 40 TO 50 PERCENT IN
THE FAR NORTH. BEST INSTABILITY...WITH LI/S DROPPING BELOW ZERO WILL
BE IN THE NORTH...AND WILL CARRY ISOLATED THUNDERSTORMS IN THE NORTH
AND NORTHWEST PART OF THE FORECAST AREA. RAIN CHANCES WILL BE
DECREASING SUNDAY NIGHT...BUT WILL STILL WARRANT A MENTION ACROSS THE
NORTH AND WEST PART OF THE FORECAST AREA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 302 PM EDT SAT APR 6 2013
THE MODELS ARE IN DECENT AGREEMENT WITH THE GENERAL PATTERN AS THEY
TRY TO TRANSITION AN UPPER LOW NEAR FOUR CORNERS INTO THE GREAT
PLAINS ON WEDNESDAY AND THEN INTO THE OHIO VALLEY AND THEN EITHER
INTO THE GREAT LAKES ON FRIDAY AS WITH THE GFS OR INTO THE DAKOTAS
AS FORECAST BY THE ECMWF. MANY OF THE SOLUTIONS FAVOR THE FASTER
GFS...HOWEVER THEY HAVE BEEN PLAGUED BY SOME RUN TO RUN
INCONSISTENCIES. THE FORECAST FAVORS THE SLOWER ECMWF FORECAST. WITH
THIS TYPE OF SYNOPTIC SITUATION...THE MODELS ARE CONSISTENTLY TOO
QUICK IN KICKING OUT THE LOW. CONFIDENCE THROUGH THURSDAY IS FAIRLY
HIGH BUT THEN DROPS STEEPLY FOR FRIDAY AND BEYOND DUE TO THE TIMING
ISSUES FROM THE FRONT.
SOME SHORT WAVES WILL BE MOVING THROUGH THE UPPER LOW AND AS THEY DO
THEY WILL GENERATE WAVES ON THE QUASI STATIONARY FRONT WHICH WILL
SET UP JUST TO THE NORTH OF THE AREA. THE EXACT LOCATION WHERE THIS
FRONT SETS UP COULD MAKE A BIG DIFFERENCE IN HOW FAR SOUTH THE FRONT
SAGS. THIS WILL CONSEQUENCES AS TO THE WEATHER EXPECTED IN THE
NORTHERN PORTION OF THE FORECAST AREA. THE SOUTHERN AREA SHOULD NOT
REALLY BE THAT AFFECTED UNTIL THE FRONT ACTUALLY STARTS MOVING
ACROSS THE AREA ON EITHER ON FRIDAY.
FOR TEMPERATURES...STAYED CLOSE TO THE MODEL BLEND...HOWEVER HAD TO
MAKE CHANGES TO THE LOWS DUE TO THE RIDGE VALLEY TEMPERATURE
DIFFERENCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 130 AM EDT SUN APR 7 2013
VFR CONDITIONS WILL HOLD ON THROUGH THE PERIOD. AN INCREASING LOW
LEVEL JET ACROSS THE OHIO VALLEY WILL ALLOW FOR THE THREAT OF LOW
LEVEL WIND SHEAR THROUGH DAWN. AN APPROACHING COLD FRONT WILL MOVE
INTO SOUTHERN OHIO TODAY. SOME SCATTERED SHOWERS AND A FEW
THUNDERSTORMS ARE POSSIBLE...MAINLY NORTH OF THE MOUNTAIN PARKWAY.
LOWER CLOUDS AND PRECIPITATION WILL NOT LIKELY MAKE IT SOUTH OF
I-64...KEEPING THE TAF SITES DRY WITH JUST SOME HIGH CLOUDS TO
CONTEND WITH.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM...JJ
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS GRAY ME
1002 PM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES REGION TONIGHT
THEN MOVE QUICKLY ACROSS NORTHERN NEW ENGLAND AND THROUGH THE GULF
OF MAINE ON TUESDAY. THIS WILL GIVE US A PERIOD OF RAIN LATE
TONIGHT INTO TUESDAY WITH SNOW POSSIBLE OVER MORE NORTHERN AREAS.
THE LOW WILL MOVE QUICKLY OUT TO SEA TUESDAY EVENING AS FAIR
WEATHER SETTLES IN BRIEFLY. A FRONTAL SYSTEM SETS UP OVER THE
REGION AS LOW PRESSURE HEADS EAST ALONG IT TUESDAY NIGHT BRINGING
A CHANCE OF MORE RAIN LATE TUESDAY NIGHT. THE WEST TO EAST FRONT
DRAPED ACROSS THE REGION THEN PROVIDES CLOUDS AND UNSETTLED
WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST ALONG
THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF PRECIPITATION
ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING CLOUDS AND A FEW
MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY SATURDAY. HIGH PRESSURE
WILL BUILD EAST FROM THE GREAT LAKES FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...
SEA BREEZES KNOCKED TEMPS DOWN ALONG THE COAST DURING THE LAST 2
HOURS. NEVERTHELESS...NW BREEZES ALLOWED PORTLAND TO TOP OUT AT THEIR HIGHEST
TEMPERATURE OF THE YEAR...REACHING 61 DEGREES. TO ACCOMPLISH THIS
FEET...WE HAD TO MOVE HIGHER THAN THE 59 DEGREES...SET BACK ON
JANUARY 14TH!
LATEST RUC STILL SHOWS PCPN REACHING WRN PTNS OF OUR FORECAST AREA
SHORTLY AFTER MIDNIGHT. RADAR CONTS TO SHOW ECHOES MARCHING
EAST...HOWEVER...THIS PCPN WILL RUN INTO DRY AIR OVER NORTHERN NEW
ENGLAND. IN THE MEANTIME...CLOUDS WILL THICKEN AND LOWER OVER THE
REGION LATE THIS EVENING FROM WEST TO EAST.
MADE MINOR ADJUSTMENTS TO THE DEW POINT AND WIND FIELDS.
OTRW...LITTLE IN THE WAY OF CHANGES TO THE GRIDS.
PREV DISC...
SFC HIGH MOVES QUICKLY OUT TO SEA THIS EVE AS LOW PRES
MOVES E FROM THE GREAT LAKES REGION TNGT. THE LOW IS ASSOCIATED
WITH AN UPR LVL TROF THAT IS MOVING QUICKLY E THRU THE STRONG
WESTERLIES ALOFT. THE LOW WILL SPREAD CLOUDS THEN RA E INTO THE
FCST AREA OVERNIGHT. TEMP PROFILE MAY BE COLD ENOUGH FOR -SN OR
-RASN OVER OUR MORE NRN ZONES IN ME...IN PARTICULAR NRN FRANKLIN
AND CENTRAL SOMERSET COUNTIES AS WELL AS THE HIGHEST TERRAIN IN
THE WHITE MTS OF NRN NH. HOWEVER...ANY ACCUMULATION WILL BE LGT IF
ANY AT ALL.
TEMPS WILL STAY MILD RANGING FROM THE MID 30S N TO THE LOWER 40S S
EXCEPT FOR SOME LOWER 30S ACROSS FAR NRN ZONES WHERE THE -SN IS
PSBL. LGT WINDS WILL TURN TO AN EASTERLY DIRECTION AHEAD OF THE
APPROACHING LOW.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE NEAR TERM
FCST.
&&
.SHORT TERM /TUESDAY NIGHT/...
THE UPR LVL SHORT WAVE TROF MOVES QUICKLY TO THE E AS THE UPR LVL
FLOW CONTINUES VERY STRONG ON TUESDAY. THIS BRINGS THE SFC LOW
ACROSS NRN NEW ENGLAND TUESDAY MORNING AND THRU THE GULF OF MAINE
TUESDAY AFTERNOON. THIS WILL CONT RA...OR SN/MIXED RASN FAR NRN
ZONES INTO TUESDAY WITH DRIER WX AND SOME CLEARING TO FOLLOW
TUESDAY AFTERNOON OVER NH AND FROM MID TO LATE AFTERNOON OVER ME.
FAIR WX TUESDAY EVE IN THE WAKE OF THE LOW. HOWEVER...A FNT SETS
UP OVER THE REGION WITH WEAK LOW PRES APPROACHING FROM THE W. THIS
WILL BRING MORE CLOUDS BACK IN WITH A CHC OF RA LATE TUESDAY NGT.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE SHORT TERM
FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WE BEGIN THE PERIOD WITH A FLAT RIDGE TO OUR SOUTH AND AN UPPER
VORTEX OVER EASTERN CANADA WITH FORECAST AREA JUST TO THE SOUTH OF
THE MEAN JET AXIS. UPSTREAM...AN UPPER TROUGH WILL BE SITUATED
JUST TO THE LEE OF THE ROCKIES. THAT UPPER TROUGH LIFTS OUT INTO
THE GREAT LAKES BY LATE IN THE WORKWEEK WHEN FORECAST CONFIDENCE
DIMINISHES IN INCREASING MODEL SPREAD. IN THE DAILIES...A WEST TO
EAST FRONT DRAPED ACROSS THE REGION WILL PROVIDE CLOUDS AND
UNSETTLED WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST
ALONG THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF
PRECIPITATION ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING
CLOUDS AND A FEW MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY
SATURDAY. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY NIGHT/...MVFR CIG AT HIE AT 17Z TDA
WILL QUICKLY BECOME VFR AS CLOUDS DISSIPATE PER SATELLITE LOOP.
OTRW VFR THRU THIS EVE...THEN LOWERING TO MVFR/PSBL IFR IN
DEVELOPING RA LATER TNGT AND CONTINUING THRU TUESDAY MORNING OVER
NH AND INTO TUESDAY AFTERNOON OVER ME AS LOW PRES MOVES E FROM
THE GREAT LAKES AND THRU NRN NEW ENGLAND. IMPROVING WX TUESDAY
AFTERNOON AS THE LOW MOVES QUICKLY THRU THE GULF OF MAINE.
LONG TERM...
WED - THU...AREAS OF MVFR POSSIBLE IN RAIN SHOWERS.
FRI...MVFR LIKELY IN RAIN WITH LCL IFR POSSIBLE IN FOG.
SFC WND GUSTS TO 25 KT POSSIBLE VCNTY OF COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...HIGH PRES MOVES E
THIS EVE FOLLOWED BY APPROACHING LOW PRES FROM THE GREAT LAKES
TNGT. THE LOW MOVES THRU NRN NEW ENGLAND TUESDAY MORNING THEN
QUICKLY THRU THE GULF OF MAINE TUESDAY AFTERNOON. PRES PATTERN
WEAK THIS EVE BUT INCREASES WITH THE PASSING LOW...BUT NOT ENOUGH
TO GENERATE SCA LEVEL WINDS. SEAS INCREASE WITH THE SYSTEM MOVING
THRU BUT NOT TO SCA LEVELS FOR MOST OF THE WATERS. THE OUTER MOST
WATERS MAY REACH THE 5 FT SCA CRITERIA FOR A BRIEF PERIOD AS THE
LOW MOVES BY.
LONG TERM...
THU NIGHT - FRI...SMALL CRAFT CONDITIONS ARE LIKELY.
&&
.FIRE WEATHER...
RAIN MOVING IN LATER TNGT THEN ENDING W TO E TUESDAY WILL PROVIDE
QPF OF 1/4 TO 1/2 INCH ACROSS MUCH OF THE REGION. DRY WX FOLLOWS
BRIEFLY TUESDAY EVE THEN MORE SHRA ACTIVITY MOVES IN FOR THE REST
OF THE WORK WEEK AS A FRONTAL SYSTEM FORMS AND REMAINS STAGNANT
OVER OR JUST S OF THE REGION...WITH THE BEST CHC FOR WIDESPREAD
SIGNIFICANT PRCP THURSDAY NGT THRU FRIDAY NGT. PRCP MOSTLY RA...
BUT SN OR MIXED RASN PSBL N/MT AREAS AND MAYBE EVEN FURTHER S LATE
IN THE WEEK. THE WET WX AND HIGH RH VALUES ALONG WITH FAIRLY WEAK
WINDS THRU FRIDAY SHOULD PROVIDE FOR VERY LOW FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
433 PM EDT SUN APR 7 2013
.SYNOPSIS...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. A WEAK AREA OF HIGH PRESSURE WILL
BUILD OVER THE REGION ON MONDAY. ANOTHER AREA OF LOW PRESSURE
WILL HEAD EAST FROM THE GREAT LAKES MONDAY NIGHT AND WILL MOVE
THROUGH SOUTHERN NEW ENGLAND AND OUT TO SEA ON TUESDAY. LOW
PRESSURE WILL ONCE AGAIN APPROACH FROM THE WEST TUESDAY NIGHT
LIFTING A WARM FRONT INTO CENTRAL NEW ENGLAND ON WEDNESDAY WHERE
IT WILL STALL. LOW PRESSURE MOVING NORTHEAST THROUGH THE ST
LAWRENCE VALLEY WILL LIFT THE WARM FRONT INTO NORTHERN NEW ENGLAND
ON THURSDAY. A TRAILING COLD FRONT WILL CROSS THE AREA THURSDAY
NIGHT AND WILL SLOWLY PUSH OFFSHORE ON FRIDAY. HIGH PRESSURE WILL
BUILD IN FROM THE WEST SATURDAY THROUGH SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE...
HAVE UPDATED GRIDS TO ACCOUNT FOR CURRENT CONDITIONS. WINDS
CONTINUE TO GUST BETWEEN 20 AND 30 MPH ACROSS THE FORECAST
AREA...WITH HIGHEST GUSTS ALONG THE EXPOSED COASTLINE...AND ALSO
OVER IN NH WHERE TEMPERATURES CLIMBED WELL INTO THE 50S.
HAVE REMOVED FZRA FROM TNGTS FCST AS GROUND TEMPS SEEM A LITTLE
TOO WARM WITH READINGS CURRENTLY IN THE 50S IN THE MTNS. HAVE ALSO
USED THE "SHOWERIZE" TOOL FOR TNGTS PCPN.
LATEST RUC SOLUTION PICKS UP ON CONVECTIVE LINE ALONG THE VT/NH
BORDER (AS OF 2032Z) VERY WELL. HOWEVER...THIS LINE OF PCPN SHOULD
WEAKEN SIGNIFICANTLY AS IT ENTERS THE REGION OF MUCH LOWER SURFACE
DEW POINTS.
HAVE ADJUSTED DEW POINTS BASED ON CURRENT CONDITIONS. ALSO...USED
CLOUD COVER FROM STLT FOR THE INTIAL CONDS AS CLOUD DECKS ARE
RAPIDLY CHANGING.
PREV DISC...
LOW PRESSURE CROSSING SOUTHERN CANADA WILL DRAG A COLD FRONT
THROUGH THE REGION OVERNIGHT. SHOWERS AND A FEW THUNDERSTORMS
CURRENTLY PUSHING THROUGH EASTERN NEW YORK AHEAD OF THE FRONT AND
THIS LINE WILL BRING THE BEST CHANCE OF PRECIP TO THE REGION
DURING THE EVENING HOURS. MAY SEE SOME SLEET OR SNOW GRAINS MIXING
IN IN THE NORTH BUT NOT LOOKING FOR ANY ACCUMULATIONS. SHOULD SEE
PARTIAL CLEARING DOWNWIND OF THE MOUNTAINS DURING THE EARLY
MORNING HOURS WHILE CLOUDS PERSIST IN THE NORTH. WILL SEE A
RELATIVELY MILD NIGHT WITH LOWS IN THE LOWER TO MID 30S NORTH AND
UPPER 30S TO LOWER 40S IN THE SOUTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
MOUNTAIN CLOUDS WILL GRADUALLY DIMINISH MONDAY MORNING AND SHOULD
SEE MOSTLY SUNNY SKIES ACROSS THE REGION BY AFTERNOON AS A WEAK
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. WILL SEE TEMPS
REBOUND TO ABOVE NORMAL...ALTHOUGH EXPECT AN AFTERNOON SEA BREEZE
TO CAP HIGHS IN THE MID TO UPPER 50S IN COASTAL AREAS. WARMER
SOUTHERN INTERIOR SECTIONS WILL ENJOY HIGHS IN THE LOWER TO MID 60S.
RAPID FIRE PROCESSION SHORTWAVES WILL CONTINUE MONDAY NIGHT AS LOW
PRESSURE QUICKLY HEADS EAST FROM THE GREAT LAKES. CLOUDS WILL
OVERSPREAD THE REGION FROM WEST TO EAST DURING THE EVENING HOURS
WITH RAIN MOVING INTO MUCH OF THE REGION AROUND MIDNIGHT. MAY SEE
ENOUGH COOLING FOR RAIN TO MIX WITH SLEET OR SNOW IN THE NORTH
WHERE AN INCH OR TWO OF WET SNOW MAY ACCUMULATE OVER THE HIGHER
TERRAIN. WILL ONCE AGAIN SEE MILD OVERNIGHT LOWS WITH MID TO UPPER
30S NORTH AND UPPER 30S TO LOWER 40S SOUTH.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
SFC LOW TRACKS ACROSS THE FCST AREA TUESDAY WITH RA/SHRA THRU THE
MORNING IN NH AND MIDDAY OVER ME...THEN AS THE LOW MOVES QUICKLY TO
THE E CLEARING FOLLOWS FROM W TO E. A TRAILING FNT DEVELOPS W OF THE
LOW ACROSS THE FCST AREA AND FURTHER TO THE W TUESDAY NGT. THIS FNT
SEPARATES MUCH WARMER AIR TO THE S FROM MUCH COLDER AIR TO THE N.
THE FNT SAGS SLOWLY TO THE S ON WEDNESDAY WITH VERY WEAK LOW PRES
SLIDING TO THE E ALONG THE BOUNDARY. THE FNT WAVERS WEDNESDAY NGT
THRU THURSDAY NGT AS OTHER WEAK LOWS TRACK EASTWARD ALONG IT. THE
EXACT LOCATION OF THE FNT VARIES AMONGST THE MODELS WITH THE ECMWF
THE COLDEST WITH THE BOUNDARY TO OUR S, GFS THE WARMEST WITH THE FNT
JUST TO OUR N AND THE CMC MODEL IN BETWEEN THOUGH CLOSER TO THE GFS.
EITHER WAY THE SYSTEM WILL GIVE US A PERIOD OF WET WX...MOSTLY
RA...THOUGH SOME MIX OR MAYBE SN OVER FAR NORTHERN AND MOUNTAIN ZONES
PSBL. THE GFS WARMS US UP CONSIDERABLY WITH H8 TEMPS OF PLUS 10 TO
NEARLY PLUS 15. THIS APPEARS OVERDONE THOUGH THE ECMWF WHICH IS MUCH
COLDER MAY ALSO BE OVERDONE... SO A COMPROMISE IS IN ORDER.
FINALLY THE LAST LOW MOVES E ON FRIDAY WITH A TRAILING CD FNT ALSO
PUSHING TO THE E. TIMING OF THIS SYSTEM STILL TO EARLY TO DETERMINE
WHETHER OR NOT WE SEE PRCP FOR MOST OF THE DAY OR IF IT COMES TO
AN END EARLIER ON. ALSO...THE ECMWF IS TRACKING THE LOW TO OUR S
RATHER THAN OVER US LIKE THE GFS THUS THE ECMWF MODEL PROVIDES A
BETTER CHC FOR MIXED/SN EVENT ON FRIDAY.
BEHIND THIS SYSTEM STRONG GUSTY NW WINDS USHER IN COLDER AND DRIER
AIR FRIDAY NGT AND SATURDAY. HIGH PRES BUILDS IN ON SUNDAY WITH
WEAKER WINDS AND WARMING TEMPS AS THE AIR MASS MODERATES.
GENERALLY USED BLEND OF ECMWF, GFS40, NAM, HPC GUIDANCE, GMOS AND
MEX MOS AND WNA4 FOR SEAS FOR THE LONG TERM FCST.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...AREAS OF MVFR/IFR CEILINGS TONIGHT...BECOMING VFR ON
MONDAY. MORE MVFR/IFR CEILINGS DEVELOPING AFTER MIDNIGHT MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...AN LENGTHY PERIOD OF UNSETTLED
WET WEATHER THRU THE LONG TERM PERIOD AS A FRONTAL BOUNDARY STAYS
NEARBY WHILE LOW PRES SYSTEMS TRACK E ALONG IT. THUS FREQUENT
IFR/LIFR CONDITIONS PSBL TUESDAY THRU FRIDAY.
&&
.MARINE...
SHORT TERM...CONTINUING SCA`S THROUGH TONIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...
UPDATE...
HAVE EXTENDED THE SCAS INTO MONDAY FOR THE OUTER WATERS. THIS IS
MAINLY DUE TO SEAS.
PREV DISC...
CONDITIONS MAINLY BELOW SCA
LEVELS TUESDAY THRU WEDNESDAY NGT AS FNT REMAINS NEARBY AND PRES
GRADIENT FAIRLY WEAK AS WEAK LOW PRES MOVES ALONG THE FNT.
THURSDAY THRU FRIDAY...DEPENDING ON THE MODEL SOLUTION... THERE IS
THE POTENTIAL FOR A MORE SIGNIFICANT LOW TO FORM WHICH WOULD
INCREASE WINDS AND BUILD SEAS POSSIBLY TO SCA LEVELS...OR MAYBE
INTO MINIMAL GALE FORCE OVER THE OUTER WATERS.
&&
.FIRE WEATHER...
RAIN SHOWERS WILL HELP TO DAMPEN FIRE DANGER
OVERNIGHT. WARMER TEMPS AND HIGHER DEW POINTS WILL KEEP THE REGION
ABOVE RED FLAG CRITERIA MONDAY WITH ANOTHER ROUND OF SHOWERS
COMING THROUGH MONDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1029 AM EDT SUN APR 7 2013
.SYNOPSIS...
RAIN CHANCES WILL INCREASE TODAY AS A COLD FRONT SLIDES OVER THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WHAT A DIFFERENCE 24 HOURS MAKES...SPRING HAS SEEMINGLY SPRUNG
OVER THE UPPER OHIO VALLEY. TEMPERATURES THIS MORNING HAVE ALREADY
SKYROCKETED INTO THE MID 60S AS PRE-FRONTAL MIXING COMBINED WITH
THE BONE DRY BOUNDARY LAYER HAS ALLOWED FOR 850 MB TEMPERATURES TO
MIX OUT EARLY TODAY. AS A RESULT...HIGH TEMPERATURES HAVE BEEN
RAISED ACROSS THE BOARD FOR THE AFTERNOON.
THE AFOREMENTIONED FRONTAL BOUNDARY HAS DEFINITELY FELT THE PINCH
FROM THE DRY BOUNDARY LAYER...AND IS HARDLY DISCERNIBLE ON THE
REGIONAL RADAR MOSAIC. AT THE MOMENT...ONLY A FEW ISOLATED SHOWERS
ARE NOTED ALONG THE BOUNDARY FROM CENTRAL OHIO TO NORTHWESTERN
PENNSYLVANIA. AS THE DAY CONTINUES...IT WOULD SEEM THIS SHOULD
INCREASE A BIT WITH DIURNAL INSTABILITY ADDED TO THE PICTURE.
HOWEVER...GIVEN THE DRY ENVIRONMENT...SIGNIFICANT RAINFALL ALONG
THE FRONT SEEMS INCREASINGLY UNLIKELY. AS A RESULT...QPF AND POPS
WERE CUT FOR THE AFTERNOON HOURS. AREAS SOUTHEAST OF PITTSBURGH
STILL STAND THE BEST SHOT AT SEEING SHOWERS THIS
AFTERNOON...HOWEVER WHATEVER DOES DEVELOP IS LIKELY TO BE QUITE
LIGHT. FRIES
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
MODEL CONSENSUS FAVORS A STALLING OF THE FRONT ACROSS NORTHERN
WEST VIRGINIA SUNDAY NIGHT BEFORE IT TURNS NORTHWARD AS A WARM
FRONT ON MONDAY. POPS FOR SHOWERS WERE CONTINUED THROUGH MONDAY
NIGHT BEFORE BEING INCREASED AGAIN ON TUESDAY. KEPT THUNDER
MONDAY AFTERNOON/EVENING AS THE HIGHER CAPE SUGGESTS.
WHILE AGREEMENT ON THE PLACEMENT OF THE FRONT BY TUESDAY BECOMES
LESS PRONOUNCED...THE ECMWF/GFS/NAM ALL LIKE THE IDEA OF TRACKING
A SHRTWV ALONG THE BNDRY BY THE AFTERNOON HOURS. THIS WOULD INCRS
LIFT AND SHEAR ALONG THE FRONTAL ZONE. THESE INGREDIENTS WITH SOME
WEAK INSTABILITY MAY BE SUFFICIENT TO OVERCOME A MODERATELY
STRONG CAP ALONG THE BOUNDARY. THUS...A MENTION OF THUNDERSTORMS
WAS ADDED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...CONFIDENCE IN EXTENDED FORECAST IS LOWER THAN
NORMAL...SIMILAR TO YESTERDAY. FRONT WILL STILL BE HUNG UP TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...PROBABLY TO THE NORTH OF THE REGION.
ALTHOUGH COLD FRONT WILL LIKELY BEGIN TO CROSS THE REGION ON
THURSDAY...GFS/ECMWF CANNOT DECIDE WHETHER THE COLD FRONT WILL TAKE
24 OR 48 HOURS TO PUSH ALL THE WAY THROUGH. HAVE BUMPED UP POPS TO
LIKELY THURSDAY NIGHT...BUT OTHERWISE MADE LITTLE CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WL CONTINUE THIS MRNG ALTHOUGH BROAD SWATH OF MID
LVL CLDINESS CONTS TO FLOW OVR THE UPR OH VALLEY REGION. STRONG
LOW PRES CROSSING THE GREAT LAKES WL DRAG A WEAK FRONT ACRS AREA
PORTS TODAY. GIVEN THE INITIALLY PALTRY BNDRY LAYER MSTR SUPPLY
AND EXPECTED EWD PROGRESS OF THE SPPRTG SHRTWV...FORECAST WL
FEATURE -SHRA WITH HIGH BASED CIGS AND VEERED WIND...GUSTS OF
WHICH MAY APPRCH 30 KT SHOULD NAM AND RAP MOMENTUM TRANSFER
PROGNOSIS BE REALIZED. CONFIDENCE IN MORE SIGNIFICANT OR
WIDESPREAD DETERIORATION IS NOT SUFFICIENT TO WARRANT TAF MENTION
JUST YET.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
THE BOUNDARY SHOULD SHIFT SOUTH OF THE REGION TONIGHT...THEN BE
PULLED NORTHWARD ONCE AGAIN ON MONDAY AS LOW PRES DIGS ACRS THE
GREAT LAKES. FRONT POSITIONING IS QUESTIONABLE THROUGH MUCH OF THE
WEEK...SO OCCASIONAL RESTRICTIONS SHOULD BE ANTICIPATED.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
618 AM EDT SUN APR 7 2013
.SYNOPSIS...
RAIN CHANCES WILL INCREASE TODAY AS A COLD FRONT SLIDES OVER THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TEMPERATURE TREND THIS MORNING IS A BIT WARMER THAN PREVIOUS
FCST...SO MADE SOME UPWARD ADJUSTMENT TO HOURLY NUMBERS. ALSO
ADJUSTED DEW POINTS DOWN...ALSO BASED ON LATEST TRENDS. HIGH TEMPS
WERE FORECAST USING WARMER NAM GUIDANCE. MAINTAINED WIND GUSTS NR
30 KTS GIVEN MOMENTUM TRANSFER FORECAST OF NAM AND RAP MDLS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
MODEL CONSENSUS FAVORS A STALLING OF THE FRONT ACROSS NORTHERN
WEST VIRGINIA SUNDAY NIGHT BEFORE IT TURNS NORTHWARD AS A WARM
FRONT ON MONDAY. POPS FOR SHOWERS WERE CONTINUED THROUGH MONDAY
NIGHT BEFORE BEING INCREASED AGAIN ON TUESDAY. KEPT THUNDER
MONDAY AFTERNOON/EVENING AS THE HIGHER CAPE SUGGESTS.
WHILE AGREEMENT ON THE PLACEMENT OF THE FRONT BY TUESDAY BECOMES
LESS PRONOUNCED...THE ECMWF/GFS/NAM ALL LIKE THE IDEA OF TRACKING
A SHRTWV ALONG THE BNDRY BY THE AFTERNOON HOURS. THIS WOULD INCRS
LIFT AND SHEAR ALONG THE FRONTAL ZONE. THESE INGREDIENTS WITH SOME
WEAK INSTABILITY MAY BE SUFFICIENT TO OVERCOME A MODERATELY
STRONG CAP ALONG THE BOUNDARY. THUS...A MENTION OF THUNDERSTORMS
WAS ADDED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...CONFIDENCE IN EXTENDED FORECAST IS LOWER THAN
NORMAL...SIMILAR TO YESTERDAY. FRONT WILL STILL BE HUNG UP TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...PROBABLY TO THE NORTH OF THE REGION.
ALTHOUGH COLD FRONT WILL LIKELY BEGIN TO CROSS THE REGION ON
THURSDAY...GFS/ECMWF CANNOT DECIDE WHETHER THE COLD FRONT WILL TAKE
24 OR 48 HOURS TO PUSH ALL THE WAY THROUGH. HAVE BUMPED UP POPS TO
LIKELY THURSDAY NIGHT...BUT OTHERWISE MADE LITTLE CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WL CONTINUE THIS MRNG ALTHOUGH BROAD SWATH OF MID
LVL CLDINESS CONTS TO FLOW OVR THE UPR OH VALLEY REGION. STRONG
LOW PRES CROSSING THE GREAT LAKES WL DRAG A WEAK FRONT ACRS AREA
PORTS TODAY. GIVEN THE INITIALLY PALTRY BNDRY LAYER MSTR SUPPLY
AND EXPECTED EWD PROGRESS OF THE SPPRTG SHRTWV...FORECAST WL
FEATURE -SHRA WITH HIGH BASED CIGS AND VEERED WIND...GUSTS OF
WHICH MAY APPRCH 30 KT SHOULD NAM AND RAP MOMENTUM TRANSFER
PROGNOSIS BE REALIZED. CONFIDENCE IN MORE SIGNIFICANT OR
WIDESPREAD DETERIORATION IS NOT SUFFICIENT TO WARRANT TAF MENTION
JUST YET.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
THE BOUNDARY SHOULD SHIFT SOUTH OF THE REGION TONIGHT...THEN BE
PULLED NORTHWARD ONCE AGAIN ON MONDAY AS LOW PRES DIGS ACRS THE
GREAT LAKES. FRONT POSITIONING IS QUESTIONABLE THROUGH MUCH OF THE
WEEK...SO OCCASIONAL RESTRICTIONS SHOULD BE ANTICIPATED.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
415 AM EDT SUN APR 7 2013
.SYNOPSIS...
WE EXPECT MILD, SPRING WEATHER TODAY, WITH A CHANCE OF SHOWERS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TEMPERATURE TREND THIS MORNING A BIT WARMER THAN PREVIOUS FCST, SO
MADE THE SMALL ADJUSTMENT. ALSO ADJUSTED DEW POINTS WAY DOWN. HIGH
TEMPS ON LOWER SIDE OF GUIDANCE. KEPT SOME GUSTY WINDS IN AS WE EXPECT
SOME OF THE MODERATE WIND JUST ABOVE THE SURFACE TO MIX DOWN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
MODEL CONSENSUS FAVORS A STALLING OF THE FRONT ACROSS NORTHERN
WEST VIRGINIA SUNDAY NIGHT BEFORE IT TURNS NORTHWARD AS A WARM
FRONT ON MONDAY. POPS FOR SHOWERS WERE CONTINUED THROUGH MONDAY
NIGHT BEFORE BEING INCREASED AGAIN ON TUESDAY. KEPT THUNDER
MONDAY AFTERNOON/EVENING AS THE HIGHER CAPE SUGGESTS.
WHILE AGREEMENT ON THE PLACEMENT OF THE FRONT BY TUESDAY BECOMES
LESS PRONOUNCED...THE ECMWF/GFS/NAM ALL LIKE THE IDEA OF TRACKING
A SHRTWV ALONG THE BNDRY BY THE AFTERNOON HOURS. THIS WOULD INCRS
LIFT AND SHEAR ALONG THE FRONTAL ZONE. THESE INGREDIENTS WITH SOME
WEAK INSTABILITY MAY BE SUFFICIENT TO OVERCOME A MODERATELY
STRONG CAP ALONG THE BOUNDARY. THUS...A MENTION OF THUNDERSTORMS
WAS ADDED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...CONFIDENCE IN EXTENDED FORECAST IS LOWER THAN
NORMAL...SIMILAR TO YESTERDAY. FRONT WILL STILL BE HUNG UP TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...PROBABLY TO THE NORTH OF THE REGION.
ALTHOUGH COLD FRONT WILL LIKELY BEGIN TO CROSS THE REGION ON
THURSDAY...GFS/ECMWF CANNOT DECIDE WHETHER THE COLD FRONT WILL TAKE
24 OR 48 HOURS TO PUSH ALL THE WAY THROUGH. HAVE BUMPED UP POPS TO
LIKELY THURSDAY NIGHT...BUT OTHERWISE MADE LITTLE CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WL CONTINUE THIS MRNG ALTHOUGH BROAD SWATH OF MID
LVL CLDINESS CONTS TO FLOW OVR THE UPR OH VALLEY REGION. THE ONLY
AVIATION CONCERN THIS MRNG WILL LOW LEVEL WIND SHEAR AS LLVL JET
SURGES TWD LOW PRES CROSSING THE GREAT LAKES.
THAT SYSTEM WL DRAG A WEAK FRONT ACRS AREA PORTS ON SUNDAY...GIVEN
THE INITIALLY PALTRY BNDRY LAYER MSTR SUPPLY AND EXPECTED EWD
PROGRESS OF THE SPPRTG SHRTWV...FORECAST WL FEATURE -SHRA WITH
HIGH BASED CIGS AND VEERED WIND...GUSTS OF WHICH MAY APPRCH 30 KT
SHOULD NAM AND RAP MOMENTUM TRANSFER PROGNOSIS BE REALIZED. CONFIDENCE
IN MORE SIGNIFICANT OR WIDESPREAD DETERIORATION IS NOT SUFFICIENT
TO WARRANT TAF MENTION JUST YET.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
THE BOUNDARY SHOULD SHIFT SOUTH OF THE REGION TONIGHT...THEN BE
PULLED NORTHWARD ONCE AGAIN ON MONDAY AS LOW PRES DIGS ACRS THE
GREAT LAKES. FRONT POSITIONING IS QUESTIONABLE THROUGH MUCH OF THE
WEEK...SO OCCASIONAL RESTRICTIONS SHOULD BE ANTICIPATED.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
137 AM EDT SUN APR 7 2013
.SYNOPSIS...
RAIN CHANCES WILL INCREASE TODAY AS A COLD FRONT SLIDES OVER THE
REGION.
&&
.NEAR TERM /THROUGH TODAY/...
TEMPERATURE TREND OVERNIGHT A BIT WARMER THAN PREVIOUS FCST, SO
MADE THE SMALL ADJUSTMENT. MOISTURE IS LIMITED AND THUNDER AHEAD
OF FRONT ALMOST GONE, SO WE REMOVED MENTION OF IT TODAY. HIGH
TEMPS ON LOWER SIDE OF GUIDANCE. ALSO UPPED WINDS AND ATTENDING
GUSTS BECAUSE OF LOW DEW POINTS AT SURFACE AND MODERATE WINDS
JUST ABOVE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
MODEL CONSENSUS FAVORS A STALLING OF THE FRONT ACROSS NORTHERN
WEST VIRGINIA SUNDAY NIGHT BEFORE IT TURNS NORTHWARD AS A WARM
FRONT ON MONDAY. POPS FOR SHOWERS WERE CONTINUED THROUGH MONDAY
NIGHT BEFORE BEING INCREASED AGAIN ON TUESDAY. WE ADDED THUNDER
TO MONDAY AFTERNOON/EVENING AS THE HIGHER CAPE SUGGESTS.
WHILE AGREEMENT ON THE PLACEMENT OF THE FRONT BY TUESDAY BECOMES
LESS PRONOUNCED...THE ECMWF/GFS/NAM ALL LIKE THE IDEA OF TRACKING
A SHRTWV ALONG THE BNDRY BY THE AFTERNOON HOURS. THIS WOULD INCRS
LIFT AND SHEAR ALONG THE FRONTAL ZONE. THESE INGREDIENTS WITH SOME
WEAK INSTABILITY MAY BE SUFFICIENT TO OVERCOME A MODERATELY
STRONG CAP ALONG THE BOUNDARY. THUS...A MENTION OF THUNDERSTORMS
WAS ADDED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...CONFIDENCE IN EXTENDED FORECAST IS LOWER THAN
NORMAL...SIMILAR TO YESTERDAY. FRONT WILL STILL BE HUNG UP TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...PROBABLY TO THE NORTH OF THE REGION.
ALTHOUGH COLD FRONT WILL LIKELY BEGIN TO CROSS THE REGION ON
THURSDAY...GFS/ECMWF CANNOT DECIDE WHETHER THE COLD FRONT WILL TAKE
24 OR 48 HOURS TO PUSH ALL THE WAY THROUGH. HAVE BUMPED UP POPS TO
LIKELY THURSDAY NIGHT...BUT OTHERWISE MADE LITTLE CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WL CONTINUE THIS MRNG ALTHOUGH BROAD SWATH OF MID
LVL CLDINESS CONTS TO FLOW OVR THE UPR OH VALLEY REGION. THE ONLY
AVIATION CONCERN THIS MRNG WILL LOW LEVEL WIND SHEAR AS LLVL JET
SURGES TWD LOW PRES CROSSING THE GREAT LAKES.
THAT SYSTEM WL DRAG A WEAK FRONT ACRS AREA PORTS ON SUNDAY...GIVEN
THE INITIALLY PALTRY BNDRY LAYER MSTR SUPPLY AND EXPECTED EWD
PROGRESS OF THE SPPRTG SHRTWV...FORECAST WL FEATURE -SHRA WITH
HIGH BASED CIGS AND VEERED WIND...GUSTS OF WHICH MAY APPRCH 30 KT
SHOULD NAM AND RAP MOMENTUM TRANSFER PROGNOSIS BE REALIZED. CONFIDENCE
IN MORE SIGNIFICANT OR WIDESPREAD DETERIORATION IS NOT SUFFICIENT
TO WARRANT TAF MENTION JUST YET.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
THE BOUNDARY SHOULD SHIFT SOUTH OF THE REGION TONIGHT...THEN BE
PULLED NORTHWARD ONCE AGAIN ON MONDAY AS LOW PRES DIGS ACRS THE
GREAT LAKES. FRONT POSITIONING IS QUESTIONABLE THROUGH MUCH OF THE
WEEK...SO OCCASIONAL RESTRICTIONS SHOULD BE ANTICIPATED.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1152 PM EDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 345 PM EDT MON APR 8 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS
WEEK AS AN ACTIVE FRONTAL BOUNDARY REMAINS NEARLY STATIONARY JUST
SOUTH OF MICHIGAN. WIDESPREAD RAINFALL AMOUNTS OF THREE OR MORE
INCHES ARE POSSIBLE BY THE END OF THE WEEK.
A THREAT FOR FREEZING RAIN... SLEET AND SNOW WILL ALSO DEVELOP
WEDNESDAY NIGHT AND LINGER THROUGH FRIDAY... MAINLY ALONG AND NORTH
OF THE INTERSTATE 96 CORRIDOR... AS COLD AIR ASSOCIATED WITH A
CANADIAN HIGH PRESSURE AREA COMES DOWN FROM THE NORTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON APR 8 2013
WIND ADVISORY REMAINS IN EFFECT UNTIL 8 PM. THE CENTER OF THE
COMPACT/IMPRESSIVE SFC LOW WAS NEAR MKG AT 3 PM AND EVEN HAS AN
"EYE" ASSOCIATED WITH IT ON VISIBLE SATELLITE IMAGERY. RUC RAPID
REFRESH HAS BEEN SHOWING SFC WIND GUSTS TO 45 MPH ALONG AND SOUTH OF
THE I-96 CORRIDOR THROUGH EARLY EVENING ON THE SRN PERIPHERY OF THIS
SFC LOW. SFC TEMPS IN THE MID 60S IN THE WARM SECTOR COMBINED WITH
PARTIAL CLEARING WILL YIELD DEEPER MIXING TO BRING THE STRONG GUSTS
DOWN TO THE SFC. THE SHOWER THREAT WITH THIS INITIAL WAVE WAS
ENDING/EXITING TO THE NORTHEAST THIS AFTERNOON. TONIGHT SHOULD BE
MOSTLY DRY IN THE SUBSIDENCE BEHIND IT.
MOIST GROUND LEFT OVER BY THIS MORNINGS RAIN COMBINED WITH
DIMINISHING WINDS AND PERIOD OF DECREASING CLOUDS WILL BRING THE
POTENTIAL FOR AREAS OF FOG LATER TONIGHT. CLOUDS SHOULD BE
INCREASING AGAIN THOUGH AHEAD OF THE NEXT APCHG WAVE TOWARD DAYBREAK.
WILL CARRY CATEGORICAL POPS IN ALL FCST PERIODS FROM TUESDAY THROUGH
WEDNESDAY NIGHT AS FAVORABLE WET SYNOPTIC PATTERN PERSISTS. WE
CONTINUE TO BE IN THE RIGHT ENTRANCE REGION OF THE 150 KT UPR JET
CORE IN SRN CANADA... WITH STRONG MID LEVEL FGEN FORCING ALONG A
VERY TIGHT BAROCLINIC ZONE. ELEVATED INSTABILITY AND A PERSISTENT
40+ KT LOW LEVEL JET EAST OF THE DEEP LONGWAVE TROUGH OVER THE WRN
U.S. SHOULD RESULT IN PERIODS OF POTNL TSTMS AS WELL.
SVR WX THREAT REMAINS VERY LOW SINCE THE SFC BOUNDARY REMAINS MOSTLY
SOUTH OF MI. HOWEVER SOME EPISODES OF SMALL HAIL AND/OR LOCALLY
HEAVY
RAINFALL ARE CERTAINLY POSSIBLE. FEEL NO NEED FOR ANY FLOOD
HEADLINES IN THE SHORT TERM GIVEN THE RECENT DRY CONDITIONS... BUT
NUISANCE FLOODING COULD BECOME AN ISSUE BY MID WEEK DEPENDING ON HOW
MUCH RAIN WE SEE FROM THE NEXT FEW WAVES.
FREEZING RAIN/SLEET/SNOW BECOMES A CONCERN BY LATE WEDNESDAY NIGHT
IN
THE NRN CWFA AS THE COLD LOW LEVEL AIR MASS ASSOCIATED WITH THE
HUDSON BAY HIGH STARTS TO INFILTRATE THE REGION FROM THE NORTHEAST.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON APR 8 2013
UNSETTLED WX WILL CONTINUE THURSDAY AS THE SLOW MOVING LOW PRESSURE
SYSTEM CONTINUES TO IMPACT OUR REGION. RAIN IS EXPECTED NEAR TO
SOUTH OF I-96 THURSDAY AND THERE IS POTENTIAL FOR A RAIN SNOW MIX
ACROSS OUR NORTHERN COUNTIES THURSDAY WITH NE FLOW CAA WITH HIGH
PRESSURE OVER JAMES BAY.
NE TO NORTH FLOW CAA ACROSS OUR AREA THURSDAY NIGHT WILL RESULT IN
POTENTIAL FOR LIGHT SNOW OR A LIGHT RAIN/LIGHT SNOW MIX. ALSO CANNOT
RULE OUT SOME (LIGHT) FREEZING RAIN THURSDAY EVENING GIVEN THIS
SYNOPTIC SETUP WITH THE HIGH PRESSURE TO OUR NORTH AND SHALLOW LOW
LEVEL COLD AIR IN PLACE.
SOME LIGHT PCPN MAY EVEN LINGER INTO FRIDAY BEFORE A MORE TRANQUIL
WX PATTERN FINALLY DEVELOPS FRIDAY NIGHT THROUGH THE WEEKEND AS HIGH
PRESSURE BUILDS IN. TEMPS WILL COOL TO AROUND TEN DEGREES BELOW
NORMAL ON THE BACK SIDE OF THAT LOW PRESSURE SYSTEM LATE THURSDAY
THROUGH SATURDAY BEFORE RETURNING TO CLOSER TO NORMAL BY LATE IN THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1152 PM EDT MON APR 8 2013
IFR AND LIFR CONDITIONS WILL BECOME WIDESPREAD TONIGHT ACROSS
MUCH OF LOWER MICHIGAN AND CONTINUE INTO TUESDAY MORNING. ONLY
SLOW IMPROVEMENT IS EXPECTED ON TUESDAY AS LOW CLOUDS LINGER
DURING THE MORNING...BUT SOME RAIN MOVING IN BY THE AFTERNOON MAY
ACTUALLY HELP IMPROVE VISBYS ABOVE LIFR.
&&
.MARINE...
ISSUED AT 345 PM EDT MON APR 8 2013
SMALL BUT STRONG AREA OF LOW PRESSURE MOVING FROM MUSKEGON TO THE
SAGINAW BAY THROUGH EARLY EVENING WILL BRING PERIOD OF STRONG/GUSTY
WESTERLY WINDS MAINLY SOUTH OF WHITEHALL. WINDS/WAVES SUBSIDING
QUICKLY AFTER 8 PM. AFTER THIS EVENING... WINDS WILL BE MOSTLY
OFFSHORE THROUGH THE WEEK BUT STILL STRONG AT TIMES.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON APR 8 2013
THE WAVE THIS MORNING PRODUCED AROUND ONE HALF INCH OF RAIN WHICH IS
NOT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THE POTENTIAL EXISTS
FOR ANOTHER THREE OR MORE INCHES OF RAIN THROUGH THE END OF THE WEEK
AND THE HYDRO SITUATION WILL NEED TO BE CLOSELY MONITORED.
FORTUNATELY THE RIVERS ARE EXTREMELY LOW RIGHT NOW AND CAN HANDLE
QUITE A BIT OF RAINFALL... ESPECIALLY IF IT IS SPACED OUT OVER
SEVERAL DAYS. THE REALITY OF IT IS THAT WE REALLY NEED ALL THIS RAIN
TO GET THE RIVERS OUT OF NEAR RECORD LOW STAGES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...OSTUNO
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
901 PM EDT MON APR 8 2013
.UPDATE...
ISSUED AT 901 PM EDT MON APR 8 2013
LOW LEVEL MOISTURE WILL CONTINUE TO REMAIN TRAPPED AS PRECIPITATION
HAS JUST ABOUT ENDED. THIS HAS CAUSED AREAS OF DENSE FOG TO FORM
OVER THE HIGHLANDS OF WESTERN UPPER MICHIGAN WITH VISIBILITIES BELOW
ONE QUARTER MILE. CONDITIONS WILL NOT IMPROVE OVERNIGHT AND ISSUED A
DENSE FOG ADVISORY FOR THIS ACROSS THE FAR WEST AND NORTH CENTRAL
COUNTIES. UPSLOPE WINDS OUT OF THE NORTH TO NORTHWEST WILL CONTINUE
TO BRING IN LOW LEVEL MOISTURE FROM LAKE SUPERIOR ALSO.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 706 PM EDT MON APR 8 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
LIFR/VLIFR CONDITIONS WILL PERSIST THROUGH TUE MORNING AT ALL SITES.
AS DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND
IWD...CONDITIONS WILL IMPROVE TO VFR. AT SAW...LOW LEVEL MOISTURE
WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO KEEP THE LOW CIGS IN
THROUGH THE REST OF THE FORECAST PERIOD. AT CMX...TEMPERATURES ARE
COLD ENOUGH FOR A LITTLE FREEZING DRIZZLE OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN
BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH.
PRES GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT /7 AM CDT/ TUESDAY FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
749 PM EDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 345 PM EDT MON APR 8 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS
WEEK AS AN ACTIVE FRONTAL BOUNDARY REMAINS NEARLY STATIONARY JUST
SOUTH OF MICHIGAN. WIDESPREAD RAINFALL AMOUNTS OF THREE OR MORE
INCHES ARE POSSIBLE BY THE END OF THE WEEK.
A THREAT FOR FREEZING RAIN... SLEET AND SNOW WILL ALSO DEVELOP
WEDNESDAY NIGHT AND LINGER THROUGH FRIDAY... MAINLY ALONG AND NORTH
OF THE INTERSTATE 96 CORRIDOR... AS COLD AIR ASSOCIATED WITH A
CANADIAN HIGH PRESSURE AREA COMES DOWN FROM THE NORTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON APR 8 2013
WIND ADVISORY REMAINS IN EFFECT UNTIL 8 PM. THE CENTER OF THE
COMPACT/IMPRESSIVE SFC LOW WAS NEAR MKG AT 3 PM AND EVEN HAS AN
"EYE" ASSOCIATED WITH IT ON VISIBLE SATELLITE IMAGERY. RUC RAPID
REFRESH HAS BEEN SHOWING SFC WIND GUSTS TO 45 MPH ALONG AND SOUTH OF
THE I-96 CORRIDOR THROUGH EARLY EVENING ON THE SRN PERIPHERY OF THIS
SFC LOW. SFC TEMPS IN THE MID 60S IN THE WARM SECTOR COMBINED WITH
PARTIAL CLEARING WILL YIELD DEEPER MIXING TO BRING THE STRONG GUSTS
DOWN TO THE SFC. THE SHOWER THREAT WITH THIS INITIAL WAVE WAS
ENDING/EXITING TO THE NORTHEAST THIS AFTERNOON. TONIGHT SHOULD BE
MOSTLY DRY IN THE SUBSIDENCE BEHIND IT.
MOIST GROUND LEFT OVER BY THIS MORNINGS RAIN COMBINED WITH
DIMINISHING WINDS AND PERIOD OF DECREASING CLOUDS WILL BRING THE
POTENTIAL FOR AREAS OF FOG LATER TONIGHT. CLOUDS SHOULD BE
INCREASING AGAIN THOUGH AHEAD OF THE NEXT APCHG WAVE TOWARD DAYBREAK.
WILL CARRY CATEGORICAL POPS IN ALL FCST PERIODS FROM TUESDAY THROUGH
WEDNESDAY NIGHT AS FAVORABLE WET SYNOPTIC PATTERN PERSISTS. WE
CONTINUE TO BE IN THE RIGHT ENTRANCE REGION OF THE 150 KT UPR JET
CORE IN SRN CANADA... WITH STRONG MID LEVEL FGEN FORCING ALONG A
VERY TIGHT BAROCLINIC ZONE. ELEVATED INSTABILITY AND A PERSISTENT
40+ KT LOW LEVEL JET EAST OF THE DEEP LONGWAVE TROUGH OVER THE WRN
U.S. SHOULD RESULT IN PERIODS OF POTNL TSTMS AS WELL.
SVR WX THREAT REMAINS VERY LOW SINCE THE SFC BOUNDARY REMAINS MOSTLY
SOUTH OF MI. HOWEVER SOME EPISODES OF SMALL HAIL AND/OR LOCALLY
HEAVY
RAINFALL ARE CERTAINLY POSSIBLE. FEEL NO NEED FOR ANY FLOOD
HEADLINES IN THE SHORT TERM GIVEN THE RECENT DRY CONDITIONS... BUT
NUISANCE FLOODING COULD BECOME AN ISSUE BY MID WEEK DEPENDING ON HOW
MUCH RAIN WE SEE FROM THE NEXT FEW WAVES.
FREEZING RAIN/SLEET/SNOW BECOMES A CONCERN BY LATE WEDNESDAY NIGHT
IN
THE NRN CWFA AS THE COLD LOW LEVEL AIR MASS ASSOCIATED WITH THE
HUDSON BAY HIGH STARTS TO INFILTRATE THE REGION FROM THE NORTHEAST.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON APR 8 2013
UNSETTLED WX WILL CONTINUE THURSDAY AS THE SLOW MOVING LOW PRESSURE
SYSTEM CONTINUES TO IMPACT OUR REGION. RAIN IS EXPECTED NEAR TO
SOUTH OF I-96 THURSDAY AND THERE IS POTENTIAL FOR A RAIN SNOW MIX
ACROSS OUR NORTHERN COUNTIES THURSDAY WITH NE FLOW CAA WITH HIGH
PRESSURE OVER JAMES BAY.
NE TO NORTH FLOW CAA ACROSS OUR AREA THURSDAY NIGHT WILL RESULT IN
POTENTIAL FOR LIGHT SNOW OR A LIGHT RAIN/LIGHT SNOW MIX. ALSO CANNOT
RULE OUT SOME (LIGHT) FREEZING RAIN THURSDAY EVENING GIVEN THIS
SYNOPTIC SETUP WITH THE HIGH PRESSURE TO OUR NORTH AND SHALLOW LOW
LEVEL COLD AIR IN PLACE.
SOME LIGHT PCPN MAY EVEN LINGER INTO FRIDAY BEFORE A MORE TRANQUIL
WX PATTERN FINALLY DEVELOPS FRIDAY NIGHT THROUGH THE WEEKEND AS HIGH
PRESSURE BUILDS IN. TEMPS WILL COOL TO AROUND TEN DEGREES BELOW
NORMAL ON THE BACK SIDE OF THAT LOW PRESSURE SYSTEM LATE THURSDAY
THROUGH SATURDAY BEFORE RETURNING TO CLOSER TO NORMAL BY LATE IN THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 748 PM EDT MON APR 8 2013
THE STRONG WINDS AT LAN AND JXN WILL BE DECREASING EARLY THIS
EVENING. THE MAIN STORY WILL BE IFR AND LIFR CONDITIONS SPREADING
EAST TONIGHT ACROSS MUCH OF LOWER MICHIGAN AND CONTINUING INTO
TUESDAY MORNING.
ONLY SLOW IMPROVEMENT IS EXPECTED ON TUESDAY AS LOW CLOUDS LINGER
DURING THE MORNING...BUT SOME RAIN MOVING IN BY THE AFTERNOON MAY
ACTUALLY HELP IMPROVE VISBYS ABOVE LIFR.
&&
.MARINE...
ISSUED AT 345 PM EDT MON APR 8 2013
SMALL BUT STRONG AREA OF LOW PRESSURE MOVING FROM MUSKEGON TO THE
SAGINAW BAY THROUGH EARLY EVENING WILL BRING PERIOD OF STRONG/GUSTY
WESTERLY WINDS MAINLY SOUTH OF WHITEHALL. WINDS/WAVES SUBSIDING
QUICKLY AFTER 8 PM. AFTER THIS EVENING... WINDS WILL BE MOSTLY
OFFSHORE THROUGH THE WEEK BUT STILL STRONG AT TIMES.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON APR 8 2013
THE WAVE THIS MORNING PRODUCED AROUND ONE HALF INCH OF RAIN WHICH IS
NOT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THE POTENTIAL EXISTS
FOR ANOTHER THREE OR MORE INCHES OF RAIN THROUGH THE END OF THE WEEK
AND THE HYDRO SITUATION WILL NEED TO BE CLOSELY MONITORED.
FORTUNATELY THE RIVERS ARE EXTREMELY LOW RIGHT NOW AND CAN HANDLE
QUITE A BIT OF RAINFALL... ESPECIALLY IF IT IS SPACED OUT OVER
SEVERAL DAYS. THE REALITY OF IT IS THAT WE REALLY NEED ALL THIS RAIN
TO GET THE RIVERS OUT OF NEAR RECORD LOW STAGES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ050-056>059-
064>067-071>074.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR LMZ844>848.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...OSTUNO
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
436 AM EDT SUN APR 7 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
FIGURING OUT THIS MESSY SPRING SYSTEM CONTINUES TO BE A DIFFICULT
PROPOSITION.
999MB SFC LOW CONTINUES TO TRACK EAST ACROSS MINNESOTA...JUST TO
SOUTH OF TWIN CITIES AS OF 19Z. SFC WARM FRONT WELL TO SOUTH ACROSS
SOUTHERN WI. TEMP OF 60F AT MSN. READINGS NEAR 40F ARE CLOSING IN ON
WI BORDER. REMAINS IN THE LOW-MID 30S ELSEWHERE...COLDEST OVR THE
KEWEENAW PENINSULA AND OUT IN THE FAR EASTERN CWA AROUND KERY.
LARGER SCALE QUITE THE MESS AS THERE ARE MULTIPLE SHORTWAVES AND
MORE OF A SPLIT TROUGH LOOK AT H7-H5. NORTHERN STREAM WAVE IS
STRONGER THAN EXPECTED AND THIS HAS ALLOWED FOR STRONGER H925-H85
TROUGH TO DRAW WARM AIR AT 975-850MB INTO UPR MICHIGAN. CURRENT
RADAR SHOWS INITIAL WARM AIR ADVECTION SNOW IS 1-2 HRS FROM ENDING
AT KERY AND THERE HAS BEEN A DECENT LULL THAT OCCURED THIS AFTN OVR
MUCH OF THE CWA...EXCEPT ACROSS THE KEWEENAW WHERE SNOW HAS BEEN
STEADY MOST OF THE DAY.
UPSTREAM THOSE MULTIPLE SHORTWAVE TROUGHS ARE RESULTING IN MANY
AREAS OF PRECIPITATION. STRONGEST AREA OF PRECIP IS TIED TO
NORTHERN WAVE...WITH WIDESPREAD PRECIPITATION OVER NORTHEAST
MINNESOTA. CLUSTERS OF PRECIP ARE ALSO FILLING IN AHEAD OF SOUTHERN
STREAM WAVE AND SFC LOW OVER ECNTRL MN AND ALONG SFC WARM FRONT OVER
SOUTHERN WI. GRADUALLY THESE TWO SHORTWAVE TROUGHS ARE SHOWN TO PHASE
OVER WI/LK MICHIGAN TONIGHT...ALLOWING PRECIPITATION TO EXPAND OVR
MUCH OF CWA. FOLLOWING 975-950MB TEMPS FROM RUC/NAM/GFS POINTS TO
RAIN BEING DOMINANT PTYPE EARLY THIS EVENING OVER ALL BUT KEWEENAW
PENINSULA. HEAVIER PRECIPITATION MOVING OVER KDLH IN LAST HOUR HAS
PRODUCED RA/FZRA/PL/SN...EVEN AS RUC WARM LAYER WAS WELL ABOVE 0C.
THIS IS CERTAINLY THE DYNAMIC COOLING THAT MODELS WERE HINTING AT
ON FRIDAY. HINTS FROM NAM/GFS AND HRRR...WHICH IS HANDLING CURRENT
PRECIP TRENDS QUITE WELL...THAT SIMILAR SITUATION MAY OCCUR MID-LATE
EVENING OVER WESTERN THIRD OF CWA. TRIED TO SHOW THIS IN PYTPE GRIDS
AND ALSO INCREASED SNOWFALL AMOUNTS INTO 2-4 INCH RANGE FROM IRONWOOD
TO HOUGHTON AND INTO THE HURON MOUNTANS. ELSEWHERE THOUGH LATE EVENING
DO NOT EXPECT MUCH SNOW AT ALL AS WARM AIR ALOFT DOMINATES.
LATE EVENING INTO THE EARLY OVERNIGHT CHANGEOVER FROM RAIN TO SNOW
OCCURS INTO THE CNTRL AND EASTERN CWA. A COUPLE INCHES OF SNOW MAY
OCCUR WITH THE CHANGE BUT DEFORMATION HINTS FROM THE MODEL QPF
FIELDS NOT AS STRIKING/PERSISTENT. BY LATE TONIGHT...ALL PRECIP WILL
BE IN THE FORM OF SNOW...BUT PRECIP INTENSITY WILL BE ON THE WANE AS
COMMA HEAD OF LOW PRESSURE DIMINISHES. IMPROVING WEATHER ON SUNDAY
WITH LINGERING CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. ONSHORE FLOW
OFF LK SUPERIOR SHOULD KEEP TEMPS ON THE COOL SIDE OVER THE NORTH
HALF. READINGS INTO THE LOWER 40S SEEM REASONABLE IN THE SOUTH WITH
DOWNSLOPING FLOW AND MORE SUNSHINE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 435 AM EDT SUN APR 7 2013
MUCH MORE ACTIVE PERIOD THIS WEEK ALTHOUGH THE BELOW NORMAL
TEMPERATURES WILL REMAIN OVER THE AREA. FIRST SYSTEM OF NOTE
AFFECTING THE REGION ON MONDAY IS IN RESPONSE TO ENERGY EJECTING OUT
OF A WESTERN CONUS TROUGH. THIS ACTUALLY LEADS TO THREE DIFFERENT
AREAS OF PRECIPITATION/FORCING. THE FIRST AREA IS OVER THE LOWER
GREAT LAKES AND ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THAT
REGION. THE SECOND AREA IS FARTHER TO THE WEST ACROSS THE UPPER
MISSISSIPPI VALLEY AND NORTHERN PLAINS...ASSOCIATED WITH THE
TIGHTENING THERMAL GRADIENT BETWEEN THE LOW IN EASTERN COLORADO AND
A HIGH IN ALBERTA. THE THIRD AREA...THAT IS EXPECTED TO AFFECT OUR
AREA IS DUE TO AN INVERTED TROUGH FROM THE LOW IN COLORADO AND A
WEAKER SHORTWAVE MOVING THROUGH THE WSW FLOW ALOFT. THIS TROUGH WILL
SLOWLY SHIFT EAST ACROSS THE CWA ON MONDAY AND WITH THE AREA UNDER A
COUPLED JET AND BROAD SOUTHERLY WAA...WOULD EXPECT LIGHT TO MODERATE
PRECIPITATION TO OCCUR ACROSS THE AREA. THERMAL FIELD LOOKS TO SETUP
SIMILAR LOCATION WISE TO THE SYSTEM THAT AFFECT THE AREA THIS PAST
EVENING. ALL MODELS ARE SHOWING A STRONG NOSE OF WARM AIR...FROM 0C
OVER THE KEWEENAW TO 4-5C AT KMNM...AT 850MB. THIS WOULD LEAD TO
LIMITED TO NO MELTING OVER THE KEWEENAW AND COMPLETE MELTING OVER
THE SOUTH CENTRAL. PRECIPITATION TYPE THEN COMES DOWN TO LOW LEVEL
AND SURFACE TEMPS. AT THIS POINT...LOOKS LIKE INITIAL SNOW OVER THE
KEWEENAW BEFORE RAIN/SNOW IN THE AFTERNOON...AN INITIAL PERIOD OF
RAIN/SNOW/FZRA OVER THE REST OF THE WEST/CENTRAL BEFORE GOING TO
RAIN AND THEN MAINLY RAIN EAST WITH THE WARMER AIR COMING OFF LAKE
MICHIGAN WITH THE SOUTHEAST FLOW...WETBULB VALUES STAYING ABOVE
FREEZING...AND THE LATER ARRIVAL OF PRECIPITATION DURING THE DAY.
21Z SREF PROBABILITIES HAD A SIMILAR IDEA AND HAVE FOLLOWED A
COMBINED THICKNESS AND SREF PROBS FOR P-TYPE.
DECENT VARIABILITY IN QPF AMOUNTS FROM THE MODELS...ALTHOUGH THE
TREND HAS BEEN TOWARDS HIGHER AMOUNTS. GFS/NAM SHOWING A SWATH
OF 1 INCH QPF OVER A PORTION OF THE WESTERN CWA IN AN AREA THAT HAS
HAD A SIMILAR SIGNAL OVER THE LAST SEVERAL RUNS WITH THE FOCUS OF
THE 925-850MB WAA...SO WILL CONTINUE TO FOCUS ON THE CORRIDOR
BETWEEN KIWD/KCMX TO THE WEST AND KIMT/KP53 TO THE EAST FOR THE
HIGHEST POPS/QPF. ON A POSITIVE NOTE...THAT AREA IS ONE OF THE
LONGER TERM DRIER AREAS OF THE CWA...ESPECIALLY IN THE MICHIGAMME
RIVER BASIN...SO ADDITIONAL PRECIPITATION WILL BE GOOD FOR
HYDROLOGIC USES BUT NOT AS MUCH FOR SPRING SNOWMELT POTENTIAL. WITH
THE REGIONAL GEM ALSO SHOWING HEAVIER PRECIP DURING THAT TIME...WILL
MAKE A SIGNIFICANT JUMP TO THE QPF VALUES /MORE THAN DOUBLE IN SOME
AREAS/ ALTHOUGH NOT AS HIGH AS SOME OF THE MODELS ARE SHOWING. HAVE
MENTIONED A COUPLE HOUR PERIOD OF MAINLY FREEZING RAIN AROUND
DAYBREAK. WITH THIS OCCURRING AROUND THE MORNING COMMUTE...COULD BE
QUITE SLICK AND WILL CONTINUE TO MENTION THE FREEZING RAIN IN THE
HWO.
AS THE TROUGH SHIFTS TO THE EAST...EXPECT COOLER AIR TO SLIDE
SOUTHEAST ACROSS THE AREA AND TRANSITION THE PRECIPITATION TO SNOW.
BUT THE LOSS OF DEEP MOISTURE AND FORCING /SHORTWAVE HAS
DEPARTED/...THINK ANY SNOWFALL ACCUMULATIONS WILL BE LIGHT DURING
THE EVENING AND EARLY OVERNIGHT HOURS. IN ADDITION...THIS LOSS OF
MOISTURE COULD LEAD IT TO BE MORE OF A DRIZZLE/FREEZING DRIZZLE
SITUATION INSTEAD OF SNOW...SO ADDED THAT IN OVER THE NW HALF OF
THE CWA TOWARDS THE OVERNIGHT HOURS.
HIGH PRESSURE THEN SETTLES IN OVER THE UPPER GREAT LAKES FOR
TUESDAY AND SHOULD LEAD TO A QUIET...BUT ONCE AGAIN BELOW NORMAL
TEMPERATURES. EXPECT THERE TO BE LINGERING LOW CLOUDS IN THE
MORNING OVER MUCH OF THE AREA AND THEN AS THOSE CLOUDS DIMINISH THE
AREA WILL SEE INCREASING MID-HIGH CLOUDS AHEAD OF THE NEXT
SHORTWAVE APPROACHING THE AREA. SO ALL IN ALL...EXPECT A MOSTLY
CLOUDY DAY FOR MOST OF THE CWA. THERE IS ALSO THE POTENTIAL THAT
PRECIPITATION FROM THE NEXT WAVE COULD SLIDE IN DURING THE LATE
AFTERNOON HOURS AND HAVE SLIGHT CHANCES TO ACCOUNT FOR THAT.
THE UNCERTAIN PORTION OF THE FORECAST THEN SETS UP FOR TUESDAY
NIGHT THROUGH THE REST OF THE WORK WEEK. WITH A LARGE UPPER TROUGH
SETUP OVER THE SOUTHWESTERN CONUS...THE FORECAST DEPENDS ON
SEVERAL WAVES EJECTING OUT OF THE UPPER TROUGH AROUND MID WEEK AND
THEN THE TROUGH ITSELF SHIFTING EAST ON THURSDAY AND THURSDAY NIGHT.
SEEMS LIKE THE MODELS HAVE THE GENERAL IDEA OF THE UPPER GREAT
LAKES BEING ON THE NORTHERN FRINGE OF THESE WAVES AND THEIR
ASSOCIATED PRECIPITATION. THEIR DIFFERENCES LARGELY DEPEND ON
THE LOCATION OF THE UPPER TROUGH SPINNING EAST OF HUDSON BAY AND
THE ASSOCIATED HIGH TO THE SOUTHWEST OF THAT. THE 12Z ECMWF HAS A
FARTHER SOUTH SOLUTION...WHICH KEEPS MUCH OF THE PRECIPITATION AND
EXITING WAVES TO THE SOUTH...WHILE THE GEM/GFS ARE A LITTLE FARTHER
NORTH. LATE ARRIVING 00Z ECMWF DID TREND A LITTLE FARTHER NORTH AND
BRUSHES THE SOUTHEAST THIRD OF THE CWA WITH PRECIP. THESE
DIFFERENCES LEAD TO SOME CONCERN TO THE FORECAST...AS THE 00Z RUN OF
THE GFS/GEM PUTS OVER AN INCH OF QPF OVER KMNM FOR TUESDAY NIGHT
INTO WEDNESDAY MORNING...WHILE THE 12Z ECMWF HAD 0.00 AND THE 00Z
RUN AROUND 0.15IN. BASED OFF GFS BUFKIT SOUNDINGS...WOULD EXPECT A
MIX OF SLEET/SNOW/FREEZING RAIN OVER THE SOUTH CENTRAL IF THAT
SOLUTION WAS CORRECT.
THE FIRST TWO WAVES WILL AFFECT THE AREA ON TUESDAY NIGHT AND THEN
ON WEDNESDAY. WHILE HIGHLIGHT BOTH OF THESE WAVES WITH CHANCE POPS
OVER THE FAR SOUTHEAST AND THEN SLOWLY TAPER TO SLIGHT CHANCES TO
THE NORTHWEST. WILL HAVE SLIGHTLY HIGHER POPS FOR THURSDAY INTO
THURSDAY NIGHT SINCE THE MAIN TROUGH WILL BE PUSHING THROUGH THE
AREA...ALTHOUGH QPF AMOUNTS SHOULD BE ON THE LIGHT SIDE. 00Z
MODEL RUNS HAVE COME INTO BETTER AGREEMENT FOR FRIDAY INTO
SATURDAY...WITH A HIGH PRESSURE RIDGE SETTING UP OVER THE CWA.
HAVE SHIFTED THE FORECAST TOWARDS A DRY SOLUTION FOR FRIDAY
AND FRIDAY NIGHT...BUT DID LEAVE SOME SLIGHT CHANCES IN ON
SATURDAY AS THE NEXT WAVE APPROACHES THE AREA. AS FOR PRECIPITATION
TYPE FROM TUESDAY NIGHT ON...APPEARS THERE WILL BE ENOUGH COLD AIR
TO KEEP PRECIPITATION MAINLY AS SNOW AND HAVE FOLLOWED THICKNESS
FIELDS FOR PRECIP TYPES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 420 AM EDT SUN APR 7 2013
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW OVER THE AREA
HAS CAUSED A WINTRY MIX OF RAIN AND SNOW THIS EVENING...WITH ALL TAF
SITES REPORTING PRECIP AND LOW CIGS AND VIS. BY THE BEGINNING OF THE
TAF PERIOD...RAIN WILL HAVE CHANGED OVER TO ALL SNOW...WITH LOW VIS
AND CIGS EXPECTED TO SLOWLY LIFT AS BEST MOISTURE MOVES EASTWARD /AS
IS REFLECTED IN LATEST OBS FROM KIWD WHERE INTENSITY OF SNOW HAS
DECREASED AND VIS HAS INCREASED...THOUGH CIGS STILL REMAIN LOW/
THROUGH SUNDAY MORNING. HAVE IFR CONDITIONS TO START OUT...THOUGH
SOME FLUCTUATIONS ABOVE AND BELOW ARE STILL POSSIBLE...SLOWLY
IMPROVING THROUGH THE NIGHT BEFORE -SHSN COMES TO AN END SUN MORN.
HIGH PRESSURE AND VFR CONDITIONS WILL MOVE IN OVERHEAD BRIEFLY
DURING THE DAY TOMORROW...BEFORE HIGH CLOUDS RETURN BY END OF TAF
PERIOD AHEAD OF NEXT SYSTEM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EDT SAT APR 6 2013
ACROSS LAKE SUPERIOR...SE TO E WINDS OF 15-30KT WILL BACK AROUND TO
THE N/NW TONIGHT IN THE WAKE OF LOW PRES PASSING JUST S OF LAKE
SUPERIOR. THE STRONGEST WINDS TONIGHT THRU SUN MORNING WILL BE OVER
ERN LAKE SUPERIOR. WINDS WILL THEN STEADILY DIMINISH W TO E SUN...
FALLING TO AOB 15KT...AS HIGH PRES RIDGE NOSES INTO THE UPPER LAKES.
AS THE RIDGE DEPARTS...E TO SE WINDS WILL INCREASE A BIT SUN
NIGHT/MON...BUT SHOULD REMAIN UNDER 20KT. TUE-THU...N TO NE WINDS
WILL DOMINATE AS THE UPPER LAKES WILL BE SITUATED BTWN HIGH PRES TO
THE N AND A LOW PRES TROF EXTENDING FROM THE SRN PLAINS TO THE OHIO
VALLEY. AT TIMES...WINDS WILL BE IN THE 15-25KT RANGE...DEPENDING ON
ANY WAVES OF LOW PRES TRACKING ALONG THE TROF TO THE S.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...SRF
AVIATION...JMW
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 AM EDT SUN APR 7 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
FIGURING OUT THIS MESSY SPRING SYSTEM CONTINUES TO BE A DIFFICULT
PROPOSITION.
999MB SFC LOW CONTINUES TO TRACK EAST ACROSS MINNESOTA...JUST TO
SOUTH OF TWIN CITIES AS OF 19Z. SFC WARM FRONT WELL TO SOUTH ACROSS
SOUTHERN WI. TEMP OF 60F AT MSN. READINGS NEAR 40F ARE CLOSING IN ON
WI BORDER. REMAINS IN THE LOW-MID 30S ELSEWHERE...COLDEST OVR THE
KEWEENAW PENINSULA AND OUT IN THE FAR EASTERN CWA AROUND KERY.
LARGER SCALE QUITE THE MESS AS THERE ARE MULTIPLE SHORTWAVES AND
MORE OF A SPLIT TROUGH LOOK AT H7-H5. NORTHERN STREAM WAVE IS
STRONGER THAN EXPECTED AND THIS HAS ALLOWED FOR STRONGER H925-H85
TROUGH TO DRAW WARM AIR AT 975-850MB INTO UPR MICHIGAN. CURRENT
RADAR SHOWS INITIAL WARM AIR ADVECTION SNOW IS 1-2 HRS FROM ENDING
AT KERY AND THERE HAS BEEN A DECENT LULL THAT OCCURED THIS AFTN OVR
MUCH OF THE CWA...EXCEPT ACROSS THE KEWEENAW WHERE SNOW HAS BEEN
STEADY MOST OF THE DAY.
UPSTREAM THOSE MULTIPLE SHORTWAVE TROUGHS ARE RESULTING IN MANY
AREAS OF PRECIPITATION. STRONGEST AREA OF PRECIP IS TIED TO
NORTHERN WAVE...WITH WIDESPREAD PRECIPITATION OVER NORTHEAST
MINNESOTA. CLUSTERS OF PRECIP ARE ALSO FILLING IN AHEAD OF SOUTHERN
STREAM WAVE AND SFC LOW OVER ECNTRL MN AND ALONG SFC WARM FRONT OVER
SOUTHERN WI. GRADUALLY THESE TWO SHORTWAVE TROUGHS ARE SHOWN TO PHASE
OVER WI/LK MICHIGAN TONIGHT...ALLOWING PRECIPITATION TO EXPAND OVR
MUCH OF CWA. FOLLOWING 975-950MB TEMPS FROM RUC/NAM/GFS POINTS TO
RAIN BEING DOMINANT PTYPE EARLY THIS EVENING OVER ALL BUT KEWEENAW
PENINSULA. HEAVIER PRECIPITATION MOVING OVER KDLH IN LAST HOUR HAS
PRODUCED RA/FZRA/PL/SN...EVEN AS RUC WARM LAYER WAS WELL ABOVE 0C.
THIS IS CERTAINLY THE DYNAMIC COOLING THAT MODELS WERE HINTING AT
ON FRIDAY. HINTS FROM NAM/GFS AND HRRR...WHICH IS HANDLING CURRENT
PRECIP TRENDS QUITE WELL...THAT SIMILAR SITUATION MAY OCCUR MID-LATE
EVENING OVER WESTERN THIRD OF CWA. TRIED TO SHOW THIS IN PYTPE GRIDS
AND ALSO INCREASED SNOWFALL AMOUNTS INTO 2-4 INCH RANGE FROM IRONWOOD
TO HOUGHTON AND INTO THE HURON MOUNTANS. ELSEWHERE THOUGH LATE EVENING
DO NOT EXPECT MUCH SNOW AT ALL AS WARM AIR ALOFT DOMINATES.
LATE EVENING INTO THE EARLY OVERNIGHT CHANGEOVER FROM RAIN TO SNOW
OCCURS INTO THE CNTRL AND EASTERN CWA. A COUPLE INCHES OF SNOW MAY
OCCUR WITH THE CHANGE BUT DEFORMATION HINTS FROM THE MODEL QPF
FIELDS NOT AS STRIKING/PERSISTENT. BY LATE TONIGHT...ALL PRECIP WILL
BE IN THE FORM OF SNOW...BUT PRECIP INTENSITY WILL BE ON THE WANE AS
COMMA HEAD OF LOW PRESSURE DIMINISHES. IMPROVING WEATHER ON SUNDAY
WITH LINGERING CLOUDS GIVING WAY TO AFTERNOON SUNSHINE. ONSHORE FLOW
OFF LK SUPERIOR SHOULD KEEP TEMPS ON THE COOL SIDE OVER THE NORTH
HALF. READINGS INTO THE LOWER 40S SEEM REASONABLE IN THE SOUTH WITH
DOWNSLOPING FLOW AND MORE SUNSHINE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 507 PM EDT SAT APR 6 2013
A PATTERN CHANGE STILL APPEARS TO BE IN THE OFFING OVER THE NEXT
COUPLE OF WEEKS THAT SHOULD TRANSITION THE PERSISTENT BELOW NORMAL
TEMP REGIME TOWARD A NORMAL OR ABOVE NORMAL ONE. HOWEVER...
CONFIDENCE IS NOT HIGH THAT ABOVE NORMAL TEMPS WILL ACTUALLY SET IN.
THE AO AND NAO WHICH HAVE BEEN IN A PREVAILING NEGATIVE PHASE SINCE
EARLY/MID FEB ARE STILL BOTH FORECAST TO TREND TO THE POSITIVE PHASE
WHICH SHOULD TRANSLATE TO WARMING. HOWEVER...THE GFS ENSEMBLES ARE
ROUGHLY SPLIT IN EITHER MAINTAINING A WEAK NEGATIVE NAO OR ONLY
GOING TO A SLIGHT POSITIVE PHASE. THE FORECASTED PHASE OF THE MJO
FAVORS BLO NORMAL TEMPS FOR THE UPPER LAKES THRU ABOUT MID MONTH
THEN ABOVE NORMAL LATE MONTH. SO...WHILE TEMPS OVERALL WILL LIKELY
FALL ON THE COLDER SIDE OF NORMAL FOR THE NEXT WEEK OR SO...THE
PROSPECT FOR NORMAL OR ABOVE NORMAL TEMPS SHOULD INCREASE FOR THE
LATTER PART OF APRIL. BOTH THE GFS AND ECMWF ARE SHOWING ANOTHER
TROF SETTLING INTO THE WRN CONUS IN THE 7-10DAY PERIOD...SO THAT MAY
BE THE HARBINGER OF THE POSSIBLE WARMER PATTERN TO FOLLOW...OR AT
LEAST ONE THAT IS MORE VARIABLE RATHER THAN PERSISTENTLY BLO NORMAL.
THE PATTERN WILL ALSO BE AN ACTIVE ONE ACROSS THE CONUS. AFTER
TODAYS SYSTEM AFFECTING THE UPPER LAKES...TROF AMPLIFICATION WILL
OCCUR OVER THE WRN CONUS OVER THE NEXT FEW DAYS WITH THE TROF THEN
SLOWLY TRANSLATING ACROSS THE CONUS DURING THE WEEK. THIS WILL
PROVIDE THE POTENTIAL FOR SIGNIFICANT PCPN EVENTS THRU MUCH OF THE
COMING WEEK FROM THE PLAINS EWD AS THE GULF FULLY OPENS UP. FOR
UPPER MI...THIS COULD MEAN ONE OR MORE UNWELCOMED RAIN EVENTS ON A
MELTING SNOWPACK WHICH IS STILL DEEP IN THE LAKE EFFECT AREAS OR
SIGNIFICANT SNOW COULD STILL BE ADDED. MUCH WILL DEPEND ON THE
STRENGTH OF THE ERN CANADA TROF THAT IS STILL IN PLACE UNDER THE
LINGERING...BUT WEAKENING NEGATIVE AO/NAO REGIME. IF THE TROF
REMAINS STRONG...EPISODES OF HVY PCPN ASSOCIATED WITH THE SLOWLY
PROGRESSIVE SRN STREAM TROF WILL PASS BY TO THE S...LEAVING DRIER
WEATHER TO DOMINATE HERE. WITH THE CONSIDERABLE SNOWPACK STILL IN
PLACE...A DRIER WEATHER REGIME WOULD BE HELPFUL BECAUSE THE LATER WE
GO THRU APRIL ADDING PCPN TO THE SNOWPACK WITHOUT MUCH MELTING
THE GREATER THE POTENTIAL WILL BECOME FOR A RAPID MELTDOWN AND
INCREASED FLOODING. AFTER THE FIRST WRN TROF LIFTS OUT...THE
PROSPECT OF ANOTHER DEVELOPING 7-10 DAYS DOWN THE ROAD IS A CONCERN
AS IT WOULD FAVOR THE POTENTIAL FOR MORE FREQUENT PCPN EVENTS ON THE
MELTING SNOWPACK.
AFTER SIGNIFICANT INCONSISTENCIES FOR SEVERAL DAYS AMONG ALL THE
MEDIUM RANGE GUIDANCE...MODELS ARE NOW ON BOARD WITH AN INITIAL
SHORTWAVE EJECTING INTO THE UPPER LAKES SUN NIGHT/MON AHEAD OF THE
DEVELOPING WRN TROF. WITH PRECIPITABLE WATER VALUES RISING TO
160-200 PCT OF NORMAL...A GOOD PUSH OF ISENTROPIC ASCENT PER 295K
SFC...AND FGEN FORCING UNDER RIGHT ENTRANCE REGION OF UPPER JET...
PCPN APPEARS LIKELY. BASED ON 850MB TEMPS/1000-850MB
THICKNESS...PTYPE SHOULD TRANSITION FROM SNOW OR SNOW/FZRA/RA WHEN
IT BEGINS OVERNIGHT SUN NIGHT TO MOSTLY RAIN DURING MON. THE ONLY
PLACE SOME SNOW MAY STILL MIX WITH RAIN MON AFTN IS OVER THE HIGHER
TERRAIN OF NW UPPER MI. MIGHT SEE A TRANSITION BACK TO SNOW OR A
RAIN/SNOW MIX AS THE PCPN EXITS MON NIGHT.
DURING THE MID AND LATE WEEK PERIOD...WILL LEAN FCST MORE STRONGLY
TOWARD THE ECMWF WHICH HAS NOW DEVELOPED GOOD RUN-TO-RUN CONSISTENCY
OVER THE LAST 5 RUNS WITH REGARD TO THE WRN TROF LIFTING OUT. THE
ECWMF ALSO SEEMS TO BETTER FIT THE PATTERN OF THE LINGERING BUT
WEAKENING NEGATIVE NAO WHICH HOLDS STRONGER TROFFING IN OVER SE
CANADA. IT IS ALSO ENCOURAGING TO SEE THE ONCE VERY INCONSISTENT AND
EXTREME GFS SHIFTING TOWARD SOMETHING MUCH MORE LIKE THE ECMWF (MANY
GFS RUNS SHOWED A STRONG SURGE OF SPRING WARMTH INTO UPPER LAKES
MIDWEEK AS IT TRACKED RATHER DEEP SFC LOWS THRU THE UPPER
MISSISSIPPI VALLEY). THE 00Z UKMET LENDS SUPPORT TO THE ECMWF THOUGH
IT DOES HAVE A STRONGER SFC LOW FARTHER N INTO NRN LWR MI THU IN
RESPONSE TO THE MAIN ENERGY LIFTING NE. THE GEM HAS BECOME MORE
INCONSISTENT...AND ITS 00Z/12Z RUNS APPEAR TOO FAST LIFTING TROF OUT
COMPARED TO OTHER GUIDANCE. SO...WHILE CONFIDENCE IN THE RESULTING
SENSIBLE WEATHER FOR THE FCST AREA IS STILL LOW...IT IS IMPROVED
FROM RECENT DAYS. IN INCORPORATING MORE OF THE ECMWF INTO THE
FCST...EXPECT DRY WEATHER TO PREVAIL TUE WITH SFC HIGH PRES RIDGE
NOSING INTO THE UPPER LAKES FROM THE NW. ALTHOUGH TIMING THE LIFTING
OUT OF THE WRN TROF AND ANY SHORTWAVES WILL CONTINUE TO BE
PROBLEMATIC...WILL SHOW SOME INCREASED POTENTIAL FOR PCPN WED...
MAINLY OVER THE S WHERE LOW CHC POPS WILL BE UTILIZED...BUT MORE SO
THU GIVEN THAT THE LAST 5 ECMWF RUNS HAVE BEEN POINTING TOWARD THU
AS THE DAY THE MAIN PIECE OF ENERGY AFFECTS THE AREA. PTYPE WOULD
PROBABLY BE MAINLY SNOW. GIVEN THE OPEN GULF...THE SNOW COULD BE
SIGNIFICANT...BUT THAT POTENTIAL APPEARS TO BE DIMINISHING AS THE
ECMWF HAS SHOWN A TENDENCY FOR ANY SFC LOWS TO BE WEAKER AND FARTHER
SE DUE TO THE STRONGER TROF AND CONFLUENCE ZONE IT HAS LINGERING
OVER SE CANADA...WHICH AGAIN DOES FIT THE RECENT PATTERN AS ALLUDED
TO ABOVE. THIS RESULTS IN THE BEST PUSH OF MOISTURE/WAA BEING
SUPPRESSED TO THE S AND E. WILL LINGER CHC POPS INTO FRI AS
MID/UPPER LEVEL TROF PASSES AND THEN SHOOT FOR A DRY SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 420 AM EDT SUN APR 7 2013
AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SURFACE LOW OVER THE AREA
HAS CAUSED A WINTRY MIX OF RAIN AND SNOW THIS EVENING...WITH ALL TAF
SITES REPORTING PRECIP AND LOW CIGS AND VIS. BY THE BEGINNING OF THE
TAF PERIOD...RAIN WILL HAVE CHANGED OVER TO ALL SNOW...WITH LOW VIS
AND CIGS EXPECTED TO SLOWLY LIFT AS BEST MOISTURE MOVES EASTWARD /AS
IS REFLECTED IN LATEST OBS FROM KIWD WHERE INTENSITY OF SNOW HAS
DECREASED AND VIS HAS INCREASED...THOUGH CIGS STILL REMAIN LOW/
THROUGH SUNDAY MORNING. HAVE IFR CONDITIONS TO START OUT...THOUGH
SOME FLUCTUATIONS ABOVE AND BELOW ARE STILL POSSIBLE...SLOWLY
IMPROVING THROUGH THE NIGHT BEFORE -SHSN COMES TO AN END SUN MORN.
HIGH PRESSURE AND VFR CONDITIONS WILL MOVE IN OVERHEAD BRIEFLY
DURING THE DAY TOMORROW...BEFORE HIGH CLOUDS RETURN BY END OF TAF
PERIOD AHEAD OF NEXT SYSTEM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EDT SAT APR 6 2013
ACROSS LAKE SUPERIOR...SE TO E WINDS OF 15-30KT WILL BACK AROUND TO
THE N/NW TONIGHT IN THE WAKE OF LOW PRES PASSING JUST S OF LAKE
SUPERIOR. THE STRONGEST WINDS TONIGHT THRU SUN MORNING WILL BE OVER
ERN LAKE SUPERIOR. WINDS WILL THEN STEADILY DIMINISH W TO E SUN...
FALLING TO AOB 15KT...AS HIGH PRES RIDGE NOSES INTO THE UPPER LAKES.
AS THE RIDGE DEPARTS...E TO SE WINDS WILL INCREASE A BIT SUN
NIGHT/MON...BUT SHOULD REMAIN UNDER 20KT. TUE-THU...N TO NE WINDS
WILL DOMINATE AS THE UPPER LAKES WILL BE SITUATED BTWN HIGH PRES TO
THE N AND A LOW PRES TROF EXTENDING FROM THE SRN PLAINS TO THE OHIO
VALLEY. AT TIMES...WINDS WILL BE IN THE 15-25KT RANGE...DEPENDING ON
ANY WAVES OF LOW PRES TRACKING ALONG THE TROF TO THE S.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JMW
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
940 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 935 PM CDT MON APR 8 2013
00Z SOUNDINGS INDICATE VERY WARM MID LEVEL TEMPS SURGED INTO
MISSOURI LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH LATEST
ACARS SOUNDINGS SUGGESTING THIS WARMING HAS REACHED AS FAR E AS
STL AREA. THIS DATA...COMBINED WITH LATEST SHORT-RANGE GUIDANCE...WOULD
CERTAINLY SUGGEST THAT EML WILL BE CAPPING ANY CONVECTION TRYING
TO FORM AOB 700 MB ALONG AND SOUTH OF AN MBY-STL-SLO LINE. IN N/NE
PARTS OF OUR CWA MESOANALYSIS IS INDICATING SOME WEAK LOW LEVEL
CONVERGENCE...AND SINCE CAPPING ISN`T AS INTENSE HAVE CONTINUED
SOME LOW POPS HERE UNTIL THE PREDAWN HOURS...WHEN FORCING/LIFT
TIED TO INCREASE OF LOW LEVEL JET WILL COMMENCE. HOWEVER...EVEN
THEN THE BEST FORCING WITH THIS FEATURE WILL BE FURTHER N ACROSS
IOWA/N IL...SO HAVE ADJUSTED PRECIP THREAT A BIT TO CONFINE
LIKELY POPS TO AREAS N OF UIN.
FORECAST IS PROCESSING AND WILL BE OUT IN A SECOND.
TRUETT
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE BOUNDARY LAYER HAS CONTINUED TO MOISTEN TODAY WITH SURFACE DEW
POINTS CURRENTLY IN THE MID 50S TO LOWER 60S. THIS MOISTURE COMBINED
WITH HEATING HAS RESULTED IN MODEST INSTABILITY WITH SBCAPES OF
AROUND 1200-1700 J/KG. SPC MESOANALYSIS SHOWS THERE IS ONLY WEAK
CIN ACROSS THE NRN 2/3RDS OF THE CWA AND MOST OF THE REGION HAS
EXTENSIVE CU. DESPITE THIS...THE APPARENT LACK OF A LOW LEVEL
FORCING MECHANISM/BOUNDARY HAS INHIBITED CONVECTION. MODEL QPFS
ARE OF LITTLE USE EARLY IN THE PERIOD OWING TO OVERDONE SURFACE
DEW POINTS AND INSTABILITY AND CONVECTIVE PCPN WITHIN THE MODELS.
THIS INCLUDES THE EXPLICIT CONVECTION ALLOWING MODELS. THE LATEST
SATELLITE IMAGERY SUGGESTS THE DEEPEST AND MOST AGITATED CU FIELD
RESIDES ACROSS NORTHERN MO INTO WEST CENTRAL IL AND THIS IS WHERE
THE HIGHEST POPS WILL BE FORECAST THIS EVENING. WATER VAPOR
IMAGERY AND THE RUC SHOWS SOME MINOR MID LEVEL PURTURBATIONS
UPSTREAM ACROSS THE PLAINS WHICH WILL SKIRT THIS REGION LATER
TONIGHT AND THUS NORTHERN MO INTO WEST CENTRAL IL WILL HAVE THE
HIGHEST POPS OVERNIGHT AS WELL. OVERNIGHT LOWS WILL BE QUITE MILD.
TUESDAY IS EXPECTED TO BE LARGELY DRY. THERE COULD BE SOME
RESIDUAL SHOWERS AND THUNDERSTORMS ACROSS THE FAR NORTHERN CWA IN
THE MORNING...HOWEVER THE ABSENCE OF A FOCUSING BOUNDARY AND A
STRENGTHENING EML SUGGESTS ANY OTHER CONVECTIVE POTENTIAL WILL BE
QUITE LOW AND ISOLATED. MORE IMPORTANTLY WE WILL SEE YET ANOTHER
DAY OF SEASONABLY WARM TEMPERATURES. DESPITE A GOOD DEAL OF
CU...HIGHS SHOULD RISE INTO MID 70S TO LOWER 80S.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE PERIOD FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT STILL APPEARS TO
BE QUITE ACTIVE. STILL THINKING THAT DISCRETE STORMS/CLUSTERS THAT
DEVELOP ALONG THE PLAINS COLD FRONT AND DRYLINE IN THE AFTERNOON
WILL QUICKLY GROW UPSCALE INTO A LINE/QLCS CONSIDERING THE DEEP
LAYER SHEAR VECTORS WITH ONLY A SMALL ANGLE FROM THE
BOUNDARY/FORCING. THE UPPER TROF WILL BE ONLY SLOWLY PROGRESSIVE
AS IT BECOMES MORE ELONGATED WHEN THE INITIAL UPPER LOW LIFTS NNE
AND ANOTHER SHORTWAVE DIGGS THRU THE BASE. THE NET EFFECT IS
BACKING OF THE UPPER LEVEL FLOW AND POTENTIAL SLOWING OF THE
EASTWARD MOVEMENT OF THE LINE/QLCS OVERNIGHT TUESDAY. THE NAM/CMC
GEM HAVE SLOWED CONSIDERABLY...HOWEVER THE ECMWF AND GFS CONTINUE
TO HAVE A GOOD DEAL OF QPF INTO EASTERN MO. WITH THIS IN MIND I
HAVENT MADE ANY RADICAL CHANGES. AMPLE INSTABILITY AND STRONG DEEP
LAYER SHEAR CONTINUE TO SUPPORT A SEVERE THREAT WITH ANY
THUNDERSTORMS. THE OVERALL EVOLUTION OF STORMS ON WED/WED NIGHT IS
A BIT UNCERTAIN DUE TO UNKNOWNS OF THE OVERNIGHT STORMS ON TUESDAY
NIGHT. THE COLD FRONT WILL BE SLOWLY MOVING ACROSS THE AREA AND
DEEP LAYER FORCING BOTH AHEAD AND BEHIND THE FRONT WILL BE
INCREASING THROUGH THE DAY AS HEIGHT FALLS SPREAD ACROSS THE AREA.
THIS SHOULD TRANSLATE TO WIDESPREAD COVERAGE OF STORMS BOTH ALONG
THE FRONT AND SHOWERS AND STORMS IN THE COOLER AIR. DEEP LAYER
SHEAR WILL BE STRONG AND THE DEGREE OF SEVERE WEATHER IN THE WARM
SECTOR WILL BE LARGELY DICTICATED BY THE AMOUNT OF INSTABILITY
WHICH WILL BE PRESENT...WHICH IS COMPLICATED BY CLOUD COVER AND
ONGOING STORMS IN THE MORNING. WE WILL ALSO HAVE TO KEEP AN EYE ON
ANY HEAVY RAINFALL POTENTIAL GIVEN THE SLOW MOVEMENT AND HIGH
MOISTURE CONTENT OF THE ATMOSPHERE.
MUCH COOLER CONDITIONS ARE EXPECTED ON THURSDAY WITH EXTENSIVE
CLOUDINESS WITHIN THE CYCLONIC FLOW IN THE WAKE OF THE FRONT. THE
PRESENCE OF A TRAILING VORT MAX AND COLD AIR ALOFT ALSO SUGGESTS A
CHANCE OF INSTABILITY SHOWERS. THE BELOW AVERAGE TEMPERATURES WILL
PERSIST FRIDAY WITH A SLIGHT MODERATION ON SATURDAY. TEMPERATURES
SHOULD WARM TO ABOVE AVERAGE SUNDAY INTO MONDAY AS THE FLOW ALOFT
TRANSITIONS TO QUASI-ZONAL AND SOUTHERLY LOW LEVEL FLOW GETS
UNDERWAY.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 654 PM CDT MON APR 8 2013
PRIMARY CONCERN FOR AVIATION INTERESTS TONIGHT WILL IS CHANCE OF
THUNDERSTORMS...PRIMARILY OVER NORTHEAST MISSOURI AND WEST CENTRAL
ILLINOIS BETWEEN 04Z AND 10Z. MANY UNCERTAINTIES REMAIN REGARDING
THESE STORMS INCLUDING INTENSITY AND ULTIMATE COVERAGE...BUT
CURRENT INDICATIONS ARE THAT A CLUSTER OF STORMS WILL DEVELOP OVER
NORTH CENTRAL OR NORTHEAST MISSOURI LATE THIS EVENING AND PUSH
NORTHEAST INTO IOWA AND ILLINOIS. THINK THE HIGHEST CHANCES FOR
STORMS SHOULD BE ENDING AFTER 10Z. ELSEWHERE AND
OTHERWISE...EXPECT A HIGH MVFR CIG TO DEVELOP OVERNIGHT ACROSS
MUCH OF THE AREA BETWEEN 2000-3000FT. MVFR CIGS SHOULD SCATTER OUT
DURING THE MID-LATE MORNING AS DAYTIME HEATING MIXES THE LOW
LEVELS. SHOULD SEE SOUTH-SOUTHWEST WIND INCREASE DURING THE LATE
MORNING AS WELL WITH GUSTS TO 20-25KTS.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS AND SOUTH-SOUTHEAST FLOW WILL PREVAIL
THROUGH THE EVENING HOURS. EXPECT TO SEE A CLUSTER OF STORMS
DEVELOP OVER NORTH CENTRAL OR NORTHEAST MISSOURI...LATE THIS
EVENING. WHILE THIS MAY AFFECT ARRIVING/DEPARTING FLIGHTS COMING
FROM OR GOING IN THAT DIRECTION...I DON`T EXPECT ANY STORMS TO
DIRECTLY AFFECT THE TERMINAL TONIGHT. CURRENT INDICATIONS ARE THAT
A HIGH MVFR DECK BETWEEN 2500-3000FT WILL DEVELOP LATER TONIGHT.
UNSURE OF TIMING...AND MANY GUIDANCE PRODUCTS TAKE THE CEILING
BELOW 2000FT. THINK THE HIGHER END IS MORE LIKELY GIVEN UPSTREAM
OBSERVATIONS FROM TODAY AND LAST NIGHT...AND THIS IS REFLECTED IN
THE CURRENT TAF. CIG SHOULD SCATTER OUT DURING THE MID-LATE
MORNING AS DAYTIME HEATING MIXES THE LOWER ATMOSPHERE...AND EXPECT
SOUTH-SOUTHWEST FLOW TO INCREASE WITH GUSTS TO 20-25KTS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
707 PM CDT MON APR 8 2013
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE BOUNDARY LAYER HAS CONTINUED TO MOISTEN TODAY WITH SURFACE DEW
POINTS CURRENTLY IN THE MID 50S TO LOWER 60S. THIS MOISTURE COMBINED
WITH HEATING HAS RESULTED IN MODEST INSTABILITY WITH SBCAPES OF
AROUND 1200-1700 J/KG. SPC MESOANALYSIS SHOWS THERE IS ONLY WEAK
CIN ACROSS THE NRN 2/3RDS OF THE CWA AND MOST OF THE REGION HAS
EXTENSIVE CU. DESPITE THIS...THE APPARENT LACK OF A LOW LEVEL
FORCING MECHANISM/BOUNDARY HAS INHIBITED CONVECTION. MODEL QPFS
ARE OF LITTLE USE EARLY IN THE PERIOD OWING TO OVERDONE SURFACE
DEW POINTS AND INSTABILITY AND CONVECTIVE PCPN WITHIN THE MODELS.
THIS INCLUDES THE EXPLICIT CONVECTION ALLOWING MODELS. THE LATEST
SATELLITE IMAGERY SUGGESTS THE DEEPEST AND MOST AGITATED CU FIELD
RESIDES ACROSS NORTHERN MO INTO WEST CENTRAL IL AND THIS IS WHERE
THE HIGHEST POPS WILL BE FORECAST THIS EVENING. WATER VAPOR
IMAGERY AND THE RUC SHOWS SOME MINOR MID LEVEL PURTURBATIONS
UPSTREAM ACROSS THE PLAINS WHICH WILL SKIRT THIS REGION LATER
TONIGHT AND THUS NORTHERN MO INTO WEST CENTRAL IL WILL HAVE THE
HIGHEST POPS OVERNIGHT AS WELL. OVERNIGHT LOWS WILL BE QUITE MILD.
TUESDAY IS EXPECTED TO BE LARGELY DRY. THERE COULD BE SOME
RESIDUAL SHOWERS AND THUNDERSTORMS ACROSS THE FAR NORTHERN CWA IN
THE MORNING...HOWEVER THE ABSENCE OF A FOCUSING BOUNDARY AND A
STRENGTHENING EML SUGGESTS ANY OTHER CONVECTIVE POTENTIAL WILL BE
QUITE LOW AND ISOLATED. MORE IMPORTANTLY WE WILL SEE YET ANOTHER
DAY OF SEASONABLY WARM TEMPERATURES. DESPITE A GOOD DEAL OF
CU...HIGHS SHOULD RISE INTO MID 70S TO LOWER 80S.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE PERIOD FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT STILL APPEARS TO
BE QUITE ACTIVE. STILL THINKING THAT DISCRETE STORMS/CLUSTERS THAT
DEVELOP ALONG THE PLAINS COLD FRONT AND DRYLINE IN THE AFTERNOON
WILL QUICKLY GROW UPSCALE INTO A LINE/QLCS CONSIDERING THE DEEP
LAYER SHEAR VECTORS WITH ONLY A SMALL ANGLE FROM THE
BOUNDARY/FORCING. THE UPPER TROF WILL BE ONLY SLOWLY PROGRESSIVE
AS IT BECOMES MORE ELONGATED WHEN THE INITIAL UPPER LOW LIFTS NNE
AND ANOTHER SHORTWAVE DIGGS THRU THE BASE. THE NET EFFECT IS
BACKING OF THE UPPER LEVEL FLOW AND POTENTIAL SLOWING OF THE
EASTWARD MOVEMENT OF THE LINE/QLCS OVERNIGHT TUESDAY. THE NAM/CMC
GEM HAVE SLOWED CONSIDERABLY...HOWEVER THE ECMWF AND GFS CONTINUE
TO HAVE A GOOD DEAL OF QPF INTO EASTERN MO. WITH THIS IN MIND I
HAVENT MADE ANY RADICAL CHANGES. AMPLE INSTABILITY AND STRONG DEEP
LAYER SHEAR CONTINUE TO SUPPORT A SEVERE THREAT WITH ANY
THUNDERSTORMS. THE OVERALL EVOLUTION OF STORMS ON WED/WED NIGHT IS
A BIT UNCERTAIN DUE TO UNKNOWNS OF THE OVERNIGHT STORMS ON TUESDAY
NIGHT. THE COLD FRONT WILL BE SLOWLY MOVING ACROSS THE AREA AND
DEEP LAYER FORCING BOTH AHEAD AND BEHIND THE FRONT WILL BE
INCREASING THROUGH THE DAY AS HEIGHT FALLS SPREAD ACROSS THE AREA.
THIS SHOULD TRANSLATE TO WIDESPREAD COVERAGE OF STORMS BOTH ALONG
THE FRONT AND SHOWERS AND STORMS IN THE COOLER AIR. DEEP LAYER
SHEAR WILL BE STRONG AND THE DEGREE OF SEVERE WEATHER IN THE WARM
SECTOR WILL BE LARGELY DICTICATED BY THE AMOUNT OF INSTABILITY
WHICH WILL BE PRESENT...WHICH IS COMPLICATED BY CLOUD COVER AND
ONGOING STORMS IN THE MORNING. WE WILL ALSO HAVE TO KEEP AN EYE ON
ANY HEAVY RAINFALL POTENTIAL GIVEN THE SLOW MOVEMENT AND HIGH
MOISTURE CONTENT OF THE ATMOSPHERE.
MUCH COOLER CONDITIONS ARE EXPECTED ON THURSDAY WITH EXTENSIVE
CLOUDINESS WITHIN THE CYCLONIC FLOW IN THE WAKE OF THE FRONT. THE
PRESENCE OF A TRAILING VORT MAX AND COLD AIR ALOFT ALSO SUGGESTS A
CHANCE OF INSTABILITY SHOWERS. THE BELOW AVERAGE TEMPERATURES WILL
PERSIST FRIDAY WITH A SLIGHT MODERATION ON SATURDAY. TEMPERATURES
SHOULD WARM TO ABOVE AVERAGE SUNDAY INTO MONDAY AS THE FLOW ALOFT
TRANSITIONS TO QUASI-ZONAL AND SOUTHERLY LOW LEVEL FLOW GETS
UNDERWAY.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 654 PM CDT MON APR 8 2013
PRIMARY CONCERN FOR AVIATION INTERESTS TONIGHT WILL IS CHANCE OF
THUNDERSTORMS...PRIMARILY OVER NORTHEAST MISSOURI AND WEST CENTRAL
ILLINOIS BETWEEN 04Z AND 10Z. MANY UNCERTAINTIES REMAIN REGARDING
THESE STORMS INCLUDING INTENSITY AND ULTIMATE COVERAGE...BUT
CURRENT INDICATIONS ARE THAT A CLUSTER OF STORMS WILL DEVELOP OVER
NORTH CENTRAL OR NORTHEAST MISSOURI LATE THIS EVENING AND PUSH
NORTHEAST INTO IOWA AND ILLINOIS. THINK THE HIGHEST CHANCES FOR
STORMS SHOULD BE ENDING AFTER 10Z. ELSEWHERE AND
OTHERWISE...EXPECT A HIGH MVFR CIG TO DEVELOP OVERNIGHT ACROSS
MUCH OF THE AREA BETWEEN 2000-3000FT. MVFR CIGS SHOULD SCATTER OUT
DURING THE MID-LATE MORNING AS DAYTIME HEATING MIXES THE LOW
LEVELS. SHOULD SEE SOUTH-SOUTHWEST WIND INCREASE DURING THE LATE
MORNING AS WELL WITH GUSTS TO 20-25KTS.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS AND SOUTH-SOUTHEAST FLOW WILL PREVAIL
THROUGH THE EVENING HOURS. EXPECT TO SEE A CLUSTER OF STORMS
DEVELOP OVER NORTH CENTRAL OR NORTHEAST MISSOURI...LATE THIS
EVENING. WHILE THIS MAY AFFECT ARRIVING/DEPARTING FLIGHTS COMING
FROM OR GOING IN THAT DIRECTION...I DON`T EXPECT ANY STORMS TO
DIRECTLY AFFECT THE TERMINAL TONIGHT. CURRENT INDICATIONS ARE THAT
A HIGH MVFR DECK BETWEEN 2500-3000FT WILL DEVELOP LATER TONIGHT.
UNSURE OF TIMING...AND MANY GUIDANCE PRODUCTS TAKE THE CEILING
BELOW 2000FT. THINK THE HIGHER END IS MORE LIKELY GIVEN UPSTREAM
OBSERVATIONS FROM TODAY AND LAST NIGHT...AND THIS IS REFLECTED IN
THE CURRENT TAF. CIG SHOULD SCATTER OUT DURING THE MID-LATE
MORNING AS DAYTIME HEATING MIXES THE LOWER ATMOSPHERE...AND EXPECT
SOUTH-SOUTHWEST FLOW TO INCREASE WITH GUSTS TO 20-25KTS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1242 PM CDT SUN APR 7 2013
.MESOSCALE DISCUSSION...
ISSUED AT 1241 PM CDT SUN APR 7 2013
MOISTURE CONTINUES TO SLOWLY INCREASE FROM SOUTHWEST TO NORTHEAST
INTO THE REGION. NOTICEABLY MORE HUMID WITH DECENT CUMULUS
DEVELOPMENT NOTED OVER THE PAST FEW HOURS. MID LEVEL FEATURES ARE
A BIT MESSY AT THIS POINT...WITH A MORE DEFINITIVE SHORTWAVE
OBSERVED VIA RAP INITIALIZATIONS ACROSS WESTERN PORTIONS OF
OKLAHOMA AND KANSAS. THIS FEATURE WILL BE MONITORED AS A
TRIGGERING MECHANISM FOR CONVECTION THIS AFTERNOON. EXPECTATIONS
ARE FOR A GENERAL INCREASE IN CONVECTIVE DEVELOPMENT AND COVERAGE
AS THE AFTERNOON PROGRESSES...WITH BETTER CHANCES FOR THE WESTERN
HALF OF THE OUTLOOK AREA DURING THE MID/LATE AFTERNOON HOURS.
MLCAPE IN THE 1000 TO 1250 J/KG RANGE AND MUCAPE AROUND 1500 J/KG
IS EXPECTED THIS AFTERNOON. WITH DEEP LAYER SHEAR ON THE AROUND OF
40 OR SO KNOTS...STORM MODE FAVOR SUPERCELLULAR STRUCTURES (THOUGH
A MIX OF MULTICELLS/LINE SEGMENTS IS PLAUSIBLE AS WELL). SLIGHT
RISK UPDATED AT MIDDAY BY SPC IS WELL PLACED AND WITH HAIL BEING
THE MAIN RISK. CANNOT RULE OUT LOCALIZED DAMAGING WIND GUSTS.
LATEST AVAILABLE 12Z MODEL OUTPUT AND MESOSCALE MODELS CONTINUE TO
DIFFER ON THE EVOLUTION OF CONVECTION THIS EVENING INTO THE
OVERNIGHT HOURS...THOUGH THE TREND OF HAVING STORMS FOCUSING
PROGRESSIVELY TO THE NORTH OF THE AREA IS THE OVERALL TREND. WILL
CONTINUE TO REFINE SPECIFIC EXPECTATIONS FOR THE OVERNIGHT
FORECAST SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 307 AM CDT SUN APR 7 2013
WEAK FRONTAL BOUNDARY HAD PUSHED INTO NORTHERN MISSOURI EARLY THIS
MORNING. IT HAD SET OFF A FEW SHOWERS OVER MAINLY EAST CENTRAL
MISSOURI EARLIER IN THE EVENING BUT THOSE HAVE SINCE DISSIPATED.
THIS BOUNDARY SHOULD PUSH INTO SOUTHERN MISSOURI LATER THIS
MORNING AND WILL ACT AS A FOCUS FOR THUNDERSTORM ACTIVITY LATER
IN THE DAY.
A SHORT WAVE COMING OUT OF THE ROCKIES WILL ALLOW THIS FRONT TO
STALL OUT AND PUSH BACK NORTHWARD AS A WARM FRONT. MOISTURE WILL
BE ON THE INCREASE AS WELL WITH DEW POINTS CLIMBING INTO THE MID
50S BY THIS AFTERNOON. MUCAPES SHOULD BE CLOSE TO 2000 J/KG LATE
THIS AFTERNOON WITH 0-6KM SHEAR VALUES AROUND 40 KTS. THIS SHOULD
GET STORMS GOING LATE THIS AFTERNOON WITH A CONTINUATION INTO THE
EVENING HOURS AS THE LOW LEVEL JET INCREASES. BELIEVE THAT THE
PRIMARY THREAT WILL BE LARGE HAIL ALTHOUGH WINDS CANNOT BE RULED
OUT AS WELL IF WE GET SUPERCELLS.
MONDAY WILL BE A DIFFERENT STORY. A FAIRLY STRONG ELEVATED MIXED
LAYER WILL BE IN PLACE WHICH WILL TEND TO CAP THE ATMOSPHERE OVER
THE REGION. HAVE THEREFORE KEPT POPS IN THE SLIGHT CHANCE CATEGORY
FOR MONDAY.
HIGH TEMPERATURES SHOULD HAVE NO TROUBLE MAKING IT INTO THE 70S
WITH THE AREA IN THE WARM SECTOR. WITH THE ADDITION OF THE GULF
MOISTURE...OVERNIGHT LOWS WILL BE RATHER MILD JUST MAKING IT INTO
THE MID TO UPPER 50S.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 307 AM CDT SUN
APR 7 2013
THE MAIN CONCERN WILL BE SEVERE WEATHER AND HEAVY RAIN CHANCES LATE
TUE THROUGH WED. AN UPPER LEVEL JET NOW JUST OFF THE THE U.S. PAC NW
COAST AND BRITISH COLUMBIA WILL DIG SOUTHEAST INTO THE SW
U.S...CLOSE TO THE FOUR CORNERS REGION BY 12Z TUE. THE GENERAL MODEL
CONSENSUS IS THAT A LONG WAVE POSITIVELY TILTED TROUGH AXIS WILL
EXTEND FROM THE DAKOTAS TO NEW MEXICO BY MIDDAY WED LEAVING OUR
AREA IN A REGION OF SW FLOW ALOFT. A STRONG CAP/EML WILL BE IN
PLACE TUE. MID LEVEL HEIGHT FALLS/COOLING AND LIFT WITH THE
APPROACHING UPPER LEVEL SYSTEM SHOULD ALLOW STORMS TO DEVELOP
ALONG THE DRY LINE OVER CENTRAL KS/WESTERN OK TUE AFTERNOON...AND
WITH TIME THIS CONVECTION WILL SPREAD EAST INTO EASTERN KS AND
WESTERN MO LATE TUE OR TUE EVENING. THE GFS AND GEM CONTINUE TO BE
FASTER IN BRINGING THE SFC COLD FRONT INTO THE REGION...6-12
HOURS FASTER THAN THE ECMWF...SO TIMING AND DETAILS ARE STILL UP
IN THE AIR. GIVEN SW FLOW ALOFT NOT SURE HOW LONG CONVECTION CAN
REMAIN DISCRETE BEFORE FILLING IN AND BECOME MORE OF A LINEAR
CLUSTER(S)/COMPLEX...BUT GENERAL SHEAR AND INSTABILITY SUPPORT A
CONTINUED MENTION OF A CHANCE FOR SEVERE WX.
THE WAVY SFC FRONT MAY LINGER OVER THE MS VLY TO PRODUCE PERIODS OF
POST FRONTAL HEAVIER SHOWERS/TSTMS WED BEFORE CHILLY AIR ONCE AGAIN
MAKES ANOTHER APPEARANCE WED NIGHT AND THU. A N-S ORIENTED SFC RIDGE
WILL SHIFT THROUGH THE AREA LATE IN THE WEEK WITH GENERALLY
DRY...COOL...AND QUIET WEATHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1241 PM CDT SUN APR 7 2013
FOR THE 18Z TAFS (JLN/SGF/BBG)...PRIMARY FORECAST CONCERN IS THE
POTENTIAL FOR SCATTERED THUNDERSTORMS FROM THE MIDDLE OF THIS
AFTERNOON THROUGH THIS EVENING. CONFIDENCE IN EXACT COVERAGE IS
STILL LOW...AND HAVE OPTED TO USE VCTS AT JLN AND SGF FOR THE TIME
BEING UNTIL CONFIDENCE INCREASES. HAVE KEPT BBG DRY FOR NOW...AN
ISOLATED SHOWER OR STORM CANNOT BE RULED OUT HERE...HOWEVER IT
APPEARS THE BETTER OPPORTUNITY FOR ACTIVITY WILL BE TO THE
NORTHWEST OF THE BBG AERODROME. CHANCES FOR STORMS WILL PERSIST
THROUGH THIS EVENING...WITH THE FOCUSING LIFTING NORTH OF THE
AERODROMES OVERNIGHT TONIGHT. LOW LEVEL WIND SHEAR WILL BE
PREVALENT TONIGHT AS A MODERATE LOW LEVEL JET SPREADS OVER THE
REGION. LAMP AS WELL AS MAV/MET MOS GUIDANCE CONTINUE TO HINT AT
IFR CIG DEVELOPMENT AT ALL TAF SITES THIS EVENING AND PERSISTING
INTO MONDAY. UPSTREAM OBS IN OKLAHOMA DID FLIRT WITH IFR STRATUS
AT TIMES...THOUGH NOT QUITE READY TO BITE OFF ON WIDESPREAD IFR
AFTER LOOKING AT THE SREF PROBABILITIES. HAVE MAINTAINED
DEVELOPMENT OF LOW END MVFR CIGS.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...GAGAN
SHORT TERM...GAEDE
LONG TERM...DSA
AVIATION...GAGAN
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1139 PM CDT SAT APR 6 2013
.UPDATE...
ISSUED AT 852 PM CDT SAT APR 6 2013
A WEAK COLD FRONT NOW EXTENDING FROM EASTERN IOWA SWWD THROUGH
CENTRAL MO HAS BEEN THE FOCUS OF SOME SHOWERS THIS EVENING IN
OUR CWA...WITH THUNDERSTORMS OVER EASTERN IOWA AND NW ILLINOIS.
MODELS THIS EVENING...INCLUDING THE HRRR AND RUC...HAVE
CONTINUED TO INDICATE A NARROW BAND OF SHOWERS TO PERSIST ALONG
AND JUST AHEAD OF THE FRONT AS IT MOVES THROUGH OUR CWA TONIGHT.
HAVE UPPED POPS ACROSS WEST CENTRAL IL THROUGH MIDNIGHT AND
INCLUDED A MENTION OF THUNDER GIVEN MUCAPE VALUES BETWEEN 100-200
J/KG OVER EASTERN IOWA AND NW ILLINOIS WHICH HAVE BEEN ENOUGH TO
RESULT IN A FAIRLY SOLID LINE OF THUNDERSTORMS THIS EVENING OVER
THAT AREA. HOWEVER...GIVEN MUCH OF THE FORCING REMAINS ANCHORED
NORTH OF THE CWA...A CONTINUED MENTION OF SOME SPOTTY SHOWERS
REMAINS SUFFICIENT FOR THE REMAINDER OF THE AREA. ASIDE FROM THE
AFOREMENTIONED CHANGES...THE REST OF THE FORECAST REMAINS ON TRACK
THIS EVENING...WITH ONLY MINOR CHANGES NEEDED TO ACCOUNT FOR NEAR
TERM TEMPERATURE TRENDS.
JP
&&
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 322 PM CDT SAT APR 6 2013
THE WEAK COLD FRONT NOW EXTENDING THROUGH NW MO WILL MOVE SEWD
INTO THE REGION TONIGHT AS THE ASSOCIATED SHORT WAVE TROF TRACKS
ACROSS THE UPPER MS VALLEY INTO THE GREAT LAKES. MODEL CONSENSUS
IS THE FRONT SHOULD BE IN THE VICINITY OF THE I-70 CORRIDOR AT 12Z
SUNDAY. PRESENTLY THERE IS NOT MUCH MORE THAN MID CLOUDS AND
SPINKLES OR A SPOT SHOWER AHEAD OF THE FRONT. SOME OF THE EXPLICIT
GUIDANCE SUGGESTS A NARROW BROKEN LINE OF SHOWERS/THUNDERSTORMS
WILL DEVELOP ALONG THE FRONT AS IT PUSHES INTO THE CWA. THIS LOOKS
A BIT OVERDONE HOWEVER...AS THE FORCING IS WEAK AND OBSERVED
MUCAPES ARE LESS THAN 100 J/KJ. CURRENT THINKING IS THERE MAY BE
SOME SPOTTY SHOWERS WITH THE FRONT...PRIMARILY FROM EASTERN MO
INTO WESTERN ILLINOIS. TEMPERTURES ON SUNDAY SHOULD BE AT LEAST
COMPARABLE TO TODAY.
THE EAST-WEST ORIENTED FRONT MAY OOZE A TAD FURTHER SOUTH ON
SUNDAY MORNING BUT IS EXPECTED TO BECOME QUASI-STATIONARY IN THE
VICINITY OF THE I-70 CORRIDOR IN THE AFTERNOON. THE PRECIPITATION
THREAT SEEMS TO LARGELY BE DEPENDENT ON THE INSTABILITY WHICH
LOOKS A BIT OVERDONE IN THESE INITIAL STAGES OF THE RETURN FLOW
OWING TO TOO HIGH OF SURFACE DEW POINTS. THINKING AT THIS TIME IS
THERE COULD BE SOME SCATTERED SHOWERS OR THUNDERSTORMS WITHIN THE
BROAD FRONTAL ZONE...ESPECIALLY IN CENTRAL MO. THE PRECIPITATION
CHANCES ARE EXPECTED TO RAMP UP CONSIDERABLY ON SUNDAY NIGHT
ASSOCIATED WITH FORCING VIA A MIGRATORY SHORT WAVE WITHIN THE WSW
FLOW ALOFT AND INTENSIFYING AND VEERING SWLY LLJ. THE MAIN FOCUS
SHOULD BE ALONG AND NORTH OF I-70 WITHIN THE COOL SECTOR NORTH OF
THE RETREATING BOUNDARY.
GLASS
.LONG TERM...(MONDAY THROUGH NEXT SATURDAY)
ISSUED AT 322 PM CDT SAT APR 6 2013
FROM MONDAY INTO TUESDAY THE DETAILS IN THE FORECAST BECOME A BIT
MORE DIFFICULT TO RESOLVE DUE TO MARKED DIFFERENCES IN THE POSITION
AN EAST-WEST BOUNDARY THAT WILL RESIDE ACROSS EITHER NORTHERN MO
OR FURTHER NORTH INTO IOWA. THE ECMWF HAS BEEN THE MOST INSISTENT
WITH THE MORE SRN POSITION AND THUS MUCH WETTER...WHILE THE
REMAINDER OF THE GUIDANCE SUITE KEEPS THE BOUNDARY ALONG OR NORTH
OF THE IOWA/MISSOURI BORDER WITH LESSER PRECIPITATION CHANCES. ON
MONDAY MORNING I THINK THAT ANY LINGERING THREAT OF SHOWERS AND
THUNDERSTORMS WILL BE ALIGNED WITH THE SWLY LLJ AXIS AND BY
AFTERNOON THE EML BUILDS IN STRONGLY AND RESULTS IN SUBSTANTIAL
CAPPING OF THE WARM SECTOR. THE WARM SECTOR WILL CONTINUE TO
MOISTEN AND DESTABILIZE INTO TUESDAY AND SHOULD REMAIN CAPPED TO
SURFACE BASED STORMS SOUTH OF THE FRONT. AT THIS TIME I HAVE KEPT
MY HIGHEST POPS IN THE MONDAY-TUESDAY TIME FRAME ACROSS NRN MO
INTO WEST CENTRAL ILLINOIS WHERE THE FRONT MAY EXIST...WITH POPS
TAPPERED SOUTHWARD. DEPENDING ON WHERE THE FRONT EVENTUALLY
RESIDES I COULD BE UNDERDONE OR OVERDONE WITH THE PRECIPITATION
THREAT. THE MAIN SHOW WITH THE DEEP PROGRESSIVE LONGWAVE TROF AND
ASSOCIATED SURFACE FRONT ALSO REMAINS PROBLEMATIC WITH TIMING
DIFFERENCES IN THE EASTWARD PROGRESSION AMONGST THE SLOWEST
ECMWF...AND FASTER GFS...GEFS AND CANADIAN. ONE PLAUSIBLE SCENARIO
IS THAT THE PLAINS SEVERE WEATHER EVENT ON TUESDAY WILL GROW
UPSCALE INTO A LINE/QLCS AND SHIFT EASTWARD INTO THE AREA
OVERNIGHT TUESDAY INTO WEDNESDAY MORNING. ANOTHER IS THAT THIS
LINE MAY REACH INTO WESTERN MO IN A WEAKENING STATE LATE TUESDAY
NIGHT AND THE MAIN EVENT MAYBE WED AFTERNOON AND EVENING IN THE
CWA PER THE ECMWF. THUS SOMEWHERE IN THE LATE TUESDAY NIGHT-
WEDNESDAY NIGHT TIME FRAME WE ARE LIKELY TO SEE SIGNIFICANT
CONVECTION...SOME OF WHICH COULD BE SEVERE.
A COOL DOWN IS FORECAST IN THE WAKE OF THE FRONT THURSDAY INTO
FRIDAY WITH BROAD CYCLONIC FLOW ALOFT.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1139 PM CDT SAT APR 6 2013
WEAK COLD FRONT IS SLIDING THROUGH REGION AND HAS MOVED THROUGH
KUIN AND KCOU...AND SHOULD BE MOVING THROUGH METRO AREA BETWEEN
06Z AND 08Z. WITH PASSAGE OF FRONTAL BOUNDARY...WINDS TO BECOME
LIGHT AND VARIABLE FOR THE REST OF THE OVERNIGHT HOURS. SOME
SHOWERS HAVE POPPED UP AHEAD OF FRONTAL BOUNDARY THIS
EVENING...BUT SHOULD REMAIN JUST NORTH OF METRO AREA AND MOVE OUT
BY 06Z...SO NO NEED TO MENTION IN TAFS. CIGS TO REMAIN VFR THROUGH
FORECAST PERIOD. OTHERWISE...WINDS TO PICKUP FROM THE SOUTHEAST
TO SOUTH BY MID MORNING SUNDAY AS FRONT SLIDES BACK NORTH AS A
WARM FRONT. AS FOR PCPN CHANCES...BEST CHANCES WILL BE SUNDAY
EVENING. BEST INSTABILITY AND LIFT WILL BE OVER CENTRAL MO...SO
ADDED TSTM MENTION THERE AFTER 00Z MONDAY. AS FOR REST OF TAF
SITES...NOT AS STRONG INSTABILITY...SO JUST ADDED PROB30 MENTION
FOR SHOWERS FOR SUNDAY EVENING.
SPECIFICS FOR KSTL...WEAK COLD FRONT IS SLIDING THROUGH REGION AND
SHOULD BE MOVING THROUGH METRO AREA BY 08Z. WITH PASSAGE OF
FRONTAL BOUNDARY...WINDS TO BECOME LIGHT AND VARIABLE FOR THE REST
OF THE OVERNIGHT HOURS. SOME SHOWERS HAVE POPPED UP AHEAD OF
FRONTAL BOUNDARY THIS EVENING...BUT SHOULD REMAIN JUST NORTH OF
METRO AREA AND MOVE OUT BY 06Z...SO NO NEED TO MENTION IN TAF.
CIGS TO REMAIN VFR THROUGH FORECAST PERIOD. OTHERWISE...WINDS TO
PICKUP FROM THE SOUTHEAST BY 16Z SUNDAY AS FRONT SLIDES BACK NORTH
AS A WARM FRONT. AS FOR PCPN CHANCES...BEST CHANCES WILL BE SUNDAY
EVENING. NOT AS STRONG INSTABILITY OVER METRO AREA AT THIS
TIME...SO JUST ADDED PROB30 MENTION FOR SHOWERS BETWEEN 01Z AND
05Z MONDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
310 PM MDT SUN APR 7 2013
.SHORT TERM...VALID FOR MON AND TUE...
WINTER WEATHER EVENT COMING TONIGHT INTO TUESDAY...WITH STRONG
COLD FRONTAL PASSAGE LATER TONIGHT. MUST CONTINUE TO STRESS GREAT
UNCERTAINTY IN THE DETAILS.
THERE ARE TWO PHASES WITH THIS EVENT. PHASE ONE INVOLVES
FRONTOGENETIC PCPN AS PACIFIC SHORTWAVE INTERACTS WITH CANADIAN
COLD FRONT...BEGINNING LATER THIS EVENING AND LASTING INTO
MONDAY. THIS WILL NOT BE AN UPSLOPE EVENT AS PCPN WILL BE DRIVEN
AT THE MID LEVELS...WITH BEST FORCING ACROSS OUR NORTH. TREMENDOUS
MODEL DIFFERENCES EXIST HERE...WITH NAM AND RAP KEEPING STRONGER
FRONTOGENESIS TO OUR NORTH...AND THE GFS/EC WRAPPING PCPN FURTHER
SOUTH AS MID LEVEL BAROCLINICITY DOES LIKEWISE. TOUGH FORECAST
HERE. BELIEVE ENERGY MOVING FROM SOUTHEAST OR INTO SOUTHERN ID IS
DYNAMIC AND FAR ENOUGH SOUTH TO ALLOW FOR A SOUTHERN PUSH OF
FORCING TO AN EXTENT GREATER THAN THE NAM/RAP...BUT NOT TO THE
EXTENT OF THE GFS WHICH SEEMS MUDDLED BY CONVECTIVE FEEDBACK.
INSTABILITY IS ANOTHER IMPORTANT FACTOR AS AIRMASS WILL BE FAIRLY
UNSTABLE THROUGH THE NIGHT...AGAIN SEE CONVECTIVE ACTIVITY
UPSTREAM NOW. SO...HAVE ISSUED WINTER WX ADVISORIES ACROSS OUR
NORTH FROM WHEATLAND TO FALLON COUNTIES...NORTH OF BILLINGS BUT
INCLUDING HIGHWAY 12 AND A PORTION OF I-94. GUSTY NORTH WINDS WITH
THE COLD ADVECTION WILL PRODUCE BLOWING SNOW ALONG WITH THE
ACCUMULATION...WHICH SHOULD GENERALLY RANGE FROM 1 TO 3 INCHES...
WITH MORE NORTH OF OUR CWA.
AS FOR THE CITY OF BILLINGS...MAYBE A LITTLE ACCUMULATION AFTER
MIDNIGHT BUT FEEL BRUNT OF PCPN WILL REMAIN NORTH...THOUGH WILL
SEE SCATTERED PREFRONTAL RAIN SHOWERS AND ISOLATED TSTMS THIS
EVENING. EXPECT UPSLOPE SNOW SHOWERS WITH LESS THAN AN INCH ON
MONDAY IN THE METRO AREA...WITH GUSTY WINDS AND A GENERALLY COLD
DAY.
AS A SIDE NOTE...IF MID LEVELS STAY DRY FROM BILLINGS SOUTH
TONIGHT...COULD BE SOME LIGHT FREEZING DRIZZLE ONCE TEMPS FALL
BELOW FREEZING AND LOW LEVELS MOISTEN WITH UPSLOPE NE WINDS
DEVELOPING. WILL NEED TO KEEP WATCH OF THIS.
PHASE TWO WILL BE INFLUENCED BY THE EVOLUTION OF PHASE ONE. THIS
WILL INVOLVE DEEP CENTRAL ROCKIES CLOSED LOW AS WE WILL BE NEAR
ITS NORTHERN EXTENT. A SOUTHERN PUSH OF FRONTOGENESIS TONIGHT
WOULD LIKELY RESULT IN A MORE SOUTHERN TRACK OF THE UPPER
LOW...WITH OUR AREA MORE INFLUENCED BY WEAKER/DRY NORTHERN TROF
CURRENTLY IN SOUTHERN CANADA. IF STRONGER FORCING STAYS NORTH
TONIGHT THAN WE COULD EXPECT A MORE NORTHWARD TRACK OF THE UPPER
LOW...AND STRONGER DIFFLUENCE OVER US...AND BETTER SNOW POTENTIAL
FOR OUR SOUTHERN UPSLOPE AREAS AND SOUTHEAST MT...AS THE ECMWF HAS
BEEN CONSISTENT IN SUGGESTING. LATEST GFS KEEPS THE LOW ENTIRELY
TO OUR SOUTH...SO PLENTY OF UNCERTAINTY HERE AS WELL. WILL KEEP A
MIDDLE GROUND...WITH LIKELY POPS AND SOME ACCUMULATION ACROSS OUR
SOUTH MONDAY NIGHT AND TUESDAY. WITH A MORE NORTHERN TRACK...DEEP
DENDRITIC LAYER AND UPSLOPE FLOW COULD BRING A SIGNIFICANT SNOW
EVENT TO SUCH PLACES AS SHERIDAN...BROADUS AND ALZADA...WITH PCPN
LASTING INTO TUESDAY NIGHT. OR WITH THE SOUTHERN TRACK THESE
AREAS WOULD RECEIVE VERY LITTLE PCPN WITH AN END BY TUESDAY.
PLEASE MONITOR THE FORECAST OVER THE NEXT DAY AS ADJUSTMENTS WILL
LIKELY BE NEEDED.
AS FOR THE CITY OF BILLINGS...IT DOES NOT LOOK AS IF WE WILL
RECEIVE MUCH SNOWFALL WITH PHASE TWO EITHER...AND POSSIBLY NONE.
AGAIN THIS WILL DEPEND ON EXACT TRACK OF THE UPPER LOW.
CANADIAN AIRMASS IS QUITE COLD AND TEMPS WILL BE WELL BELOW NORMAL
THE NEXT TWO DAYS. HAVE DROPPED EXPECTED TEMPS A BIT MORE. RECORD
LOWS COULD BE CHALLENGED AT BILLINGS AND MILES CITY MONDAY NIGHT.
JKL
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
CONSENSUS OF THE EXTENDED IS FOR SLIGHTLY BELOW SEASONAL AVERAGES
FOR TEMPERATURES AND AN UNSETTLED NATURE FOR POPS. THE ONLY REAL
DRY DAY APPEARS TO BE WEDNESDAY AS A SHORT LIVED MESO RIDGE MOVES
IN. A DEEP UPPER TROUGH OVER THE GULF OF ALASKA AND THE NORTHERN
TERRITORIES DROPS SOUTHWARD TOWARD THE PACIFIC NORTHWEST THIS
WEEKEND. THIS PROCESS WILL CAUSE FALLING HEIGHTS FOR A RELATIVELY
UNSTABLE ATMOSPHERE WITH MOISTURE AND SHORTWAVES SHOOTING ACROSS
THE FORECAST AREA. IMPOSSIBLE AT THIS POINT TO PIN POINT THE BEST
DAY FOR POP CHANCES AS EXACT PLACEMENT OF APPROACHING WAVES WILL
BE CRITICAL FOR ASCENT. A BROAD BRUSHED SLIGHT CHANCE TO CHANCE
POPS SEEMS THE BEST WAY TO GO. THE WARMEST DAY SHOULD BE WEDNESDAY
WITH LESS CLOUD COVER ALLOWING A HIGH SUN ANGLE TO WORK. TWH
&&
.AVIATION...
SCATTERED SHOWERS WILL PUSH ACROSS THE AREA LATE THIS AFTERNOON
AND THIS EVENING. SOME WIND GUSTS TO 30KTS WILL ACCOMPANY THE
SHOWERS WITH MAINLY LIGHT RAIN. A STRONG COLD FRONT WILL PUSH INTO
NORTHERN TERMINALS THIS EVENING AND INTO SOUTHERN TERMINALS
OVERNIGHT. THIS FRONT WILL SWITCH WINDS TO THE NORTH WITH GUSTS TO
30KTS. RAIN AND SNOW WILL DEVELOP MAINLY NORTH OF A LIVINGSTON TO
BILLINGS TO BAKER LINE THIS EVENING. THE PRECIPITATION WILL CHANGE
TO SNOW BY LATE EVENING AND CONTINUE OVERNIGHT WITH CONDITIONS
LOWERING TO IFR NORTH OF THIS LINE. LOW CLOUDS WILL SPREAD SOUTH
OVERNIGHT WITH CEILINGS LOWERING TO MVFR CATEGORIES. LIGHT
SNOW...AND POSSIBLY LIGHT FREEZING DRIZZLE...WILL ACCOMPANY THE
LOWERING CEILINGS. LOW CLOUDS...SNOW AND GUSTY NORTH WINDS WILL
CONTINUE THROUGH MONDAY MORNING. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 028/034 018/036 022/048 033/056 033/053 032/053 029/052
67/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 028/039 018/038 022/048 032/053 029/051 029/050 026/049
66/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030/035 019/035 019/047 029/057 028/054 027/054 026/054
67/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 030/032 016/033 018/044 027/052 027/052 028/052 025/052
88/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 033/036 017/031 016/041 024/052 024/051 026/051 024/051
57/S 63/S 21/B 23/W 22/W 33/W 33/W
BHK 030/031 015/029 015/038 022/045 027/046 026/046 021/046
78/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 032/037 020/031 015/043 026/054 027/051 027/052 024/051
28/S 75/S 21/B 23/W 22/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
NOON MDT MONDAY FOR ZONES 28-29-42-63.
WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 6
PM MDT MONDAY FOR ZONES 31>33.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1052 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1051 PM CDT MON APR 8 2013
UPDATED FORECAST FOR EARLIER ONSET OF WINTER WEATHER CONDITIONS
OVER NORTHWEST NEBRASKA. TRANSITION TO SNOW TO THE WEST OF A LINE
FROM CODY TO LISCO.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
DEEP CONVECTION SHOULD DEVELOP WEST TO EAST TONIGHT WITH LARGE HAIL
THE PRIMARY SEVERE WEATHER THREAT. THERE IS A NARROW WINDOW FOR
TORNADOES ASSOCIATED WITH A SOUTHWARD MOVING COLD FRONT THIS EVENING
AND STORMS DEVELOPING ALONG OR JUST SOUTH OF THE FRONT. THE
THUNDERSTORMS WILL HELP PULL COLD AIR SOUTH WHICH COULD CAUSE A
CHANGEOVER TO FREEZING RAIN FASTER THAN FORECAST.
THE RAP HAS WEAKENED THE MIDLEVEL WARM AIR ADVECTION SUFFICIENTLY TO
REDUCE THE RISK OF SLEET HOWEVER THIS WOULD SUGGEST MORE FREEZING
RAIN OR FREEZING DRIZZLE POTENTIAL TUESDAY AS THE MOISTURE IS
GENERALLY BELOW 700 MB IN ALL MODELS. THE LATEST FORECAST SHOWS LESS
QPF TUESDAY BUT SOME AREAS COULD SEE BETWEEN 1/4 AND 1/2 INCH OF
FREEZING RAIN AS THE CHANGEOVER LINE WILL SPEND MOST OF THE DAY
HOURS TRAVERSING EASTERN PORTIONS OF THE FCST AREA.
THE SNOW LINE IS A LITTLE FASTER IN THE RAP BUT THE RAIN TO FREEZING
RAIN LINE SHOULD BE DRAPED ACROSS CUSTER AND FRONTIER COUNTY BY 12Z
TUESDAY. ALL OF THIS SUGGESTS THE COLD AIR IS WINNING OUT IN THE
WEST AND TAKING A MORE NORTH TO SOUTH PLUNGE. THERE NO REAL CHANGE
IN THE SNOWFALL AMOUNTS DURING THE SHORT TERM EXCEPT HIGHER AMOUNTS
ASSOCIATED WITH THE SLIGHTLY FASTER CHANGEOVER IN THE WEST.
ICING COULD BE A REAL PROBLEM FOR THE POWER GRID IN SOME AREAS WITH
WINDS INCREASING TO 25 TO 35 MPH. TEMPERATURES SHOULD BE STEADY OR
FALLING IN THE 20S THROUGHOUT THE DAY AND WIND CHILL READINGS IN THE
SINGLE DIGITS ARE EXPECTED ALL AREAS BY TUESDAY NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
EARLY TUESDAY EVENING THE H5 UPPER LOW IS FORECAST TO ROTATE INTO
CENTRAL COLORADO WHILE THE H7 LOW MOVES INTO FAR NORTHEAST CO/SWRN
NEBR/NWRN KS. THIS WILL BE CONDUCIVE FOR A PERIOD OF MODERATE TO
HEAVY SNOW IS TO DEVELOP IN NW KS AND DRAWN NORTHWARD INTO
WESTERN NEBRASKA. NORTHWEST WINDS 25 TO 35 MPH AND GUSTY TO
PRODUCE AREAS OF BLOWING SNOW TO DIMINISH SLIGHTLY TO 20 TO 30
MPH AFTER MIDNIGHT. THE SYSTEM WILL BEGIN TO WEAKEN AS DRIER AIR
IS DRAWN INTO THE EASTERN SIDE OF THE SYSTEM. A PERSISTENT
DEFORMATION ZONE ON THE BACKSIDE OF THE SYSTEM WILL STILL BRING
LIGHT SNOW ACCUMULATIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY.
EVEN WEDNESDAY NIGHT INTO THURSDAY...THE NORTHEAST HALF OF THE
AREA MAY CONTINUE TO SEE LIGHT SNOW AS UPPER LOW ROTATES SLOWLY
EAST INTO IOWA.
HAVE TRENDED DOWN HIGH TEMPERATURES WEDNESDAY TO THE UPPER 20S AND
LOWER 30S. THURSDAY HIGHS ALSO TRENDED DOWN A BIT TO 33 TO 35
NORTH CENTRAL TO THE LOWER 40S FAR SOUTHWEST.
IN WAKE OF CLOSED SYSTEM THURSDAY...UPPER FLOW WILL BE WEST
NORTHWEST FRIDAY THROUGH MONDAY. TEMPERATURES TO MODERATE FROM
40 TO 50 FRIDAY TO THE 50S TO LOW/MID 60S SATURDAY AND SUNDAY. LOW
CHANCE POPS SUNDAY/MONDAY FOR RAIN SHOWERS...NIGHTTIME/MORNING
RAIN/SNOW SHOWERS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 642 PM CDT MON APR 8 2013
PRECIPITATION WILL CONTINUE TO EXPAND OVER WESTERN NEBRASKA EARLY
THIS EVENING. CEILINGS WILL LOWER IN TO LIFR CATEGORIES AND AS
TEMPERATURES COOL AREAS OF MIXED OR FREEZING PRECIPITATION ARE
EXPECTED TO DEVELOP. PRECIPITATION TO CHANGE TO ALL SNOW THROUGH
THE DAY ON TUESDAY. STRONG WINDS TO CONTINUE AND LIFR CEILINGS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ029-038-058-069>071.
WINTER STORM WARNING FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ006>010-024>028-035>037-056-057-
059.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ004-005-022-023-094.
&&
$$
UPDATE...POWER
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
643 PM CDT MON APR 8 2013
.AVIATION...
00Z TAFS FOR KOMA...KOFK...KLNK.
ALL THREE SITES START WITH VFR CONDITIONS INITIALLY WITH SOME
CHANCE OF SHRA OR TSRA THROUGH ABOUT 09Z. AS COLD FRONT CURRENTLY
OVER NW IOWA AND FAR NE NEBRASKA MOVES SLOWLY SOUTHEAST DURING
THE PERIOD WINDS SHIFT TO NORTHEAST AND INCREASE WITH CIGS AND
VSBY LOWERING TO IFR AND LIFR CONDITIONS. KOFK WILL FEEL THE
EFFECTS FIRST AFTER 02Z WITH KOMA AND KLNK HOLDING OFF UNTIL
AFTER 05Z.
&&
.PREV DISCUSSION... /ISSUED 322 PM CDT MON APR 8 2013/
SHORT TERM...TONIGHT THROUGH THURSDAY
STRONG SPRING STORM SYSTEM IS KNOCKING AT OUR DOOR...WITH ACTIVE
WEATHER EXPECTED FOR THE NEXT FEW DAYS. SUBJECTIVE 12Z UPPER AIR
ANALYSIS INDICATES UPPER-LEVEL TROUGH DEEPENING INTO A LOW OVER
THE GREAT BASIN...WITH 500MB HEIGHT FALLS UP TO 150M. ANOTHER
SHORTWAVE WAS ADVANCING ACROSS IA...WITH 70M HEIGHT FALLS
ASSOCIATED WITH IT. UPPER-LEVEL JET WAS STRONGEST ON THE BACK SIDE
OF THE DIGGING UPPER LOW..WITH UP TO 110KT ALONG THE PACIFIC
COAST. MOISTURE AXIS AT 850MB EXTENDED FROM TX THROUGH EASTERN
KS/WESTERN MO AS FAR NORTH AS THE NEB AND IA BORDERS...WTIH A
DEVELOPING LEE LOW IN SOUTEAST CO/OK PANDHANDLE/SOUTHWEST KS. SUB-
0C TEMPS AT 850MB EXTENDED FROM MT THROUGH ND INTO NORTHERNMOST
MN. RAP ANALYSIS AT 19Z INDICATED A SURFACE LOW IN SOUTHEAST
CO/NORTHEAST NM...WITH FRONTAL BOUNDARY EXTENDING FROM SOUTHWEST
NEB THROUGH NORTHEAST NEB AS COLD AIR BEGINS TO DESCEND OUT OF SD
WHILE WARM AIR ADVECTION CONTINUES AHEAD OF THE LOW.
MAIN FORECAST CONCERNS INCLUDE CONVECTIVE POTENTIAL THIS EVENING AND
TONIGHT AND IN THE SOUTHERN CWA THROUGH TUESDAY...AS WELL AS WINTER
WEATHER POTENTIAL IN THE NORTHWEST CWA EARLY TUESDAY MORNING THROUGH
WEDNESDAY. LINGERING CLOUDS ARE INHIBITING WARMING IN THE
SOUTH...WHICH MIGHT MAKE REACHING CONVECTIVE TEMPERATURE A
CHALLENGE. STORMS ARE LIKELY TO FIRE THIS AFTERNOON FURTHER WEST IN
KS...AND MOVE ACROSS NORTHERN KS/SOUTHERN NEB LATER THIS EVENING
THROUGH TONIGHT. MEANWHILE...COLD FRONT DESCENDING OUT OF SD IS
LIKELY TO REACH THE NORTHERN CWA THIS EVENING/TONIGHT...AND SHOULD
BEGIN TO SEE RAIN ALONG THAT FRONT AS WELL. HAVE INCLUDED THUNDER
MENTION EVERYWHERE THIS EVENING...BUT STARTED TO TAKE IT OUT OF THE
NORTHERN CWA AFTER MIDNIGHT. DOES APPEAR THAT SURFACE TEMPS WILL
REMAIN ABOVE FREEZING THROUGH THE NIGHT ACROSS THE AREA...AND THUS
HAVE INDICATED RAIN...BUT SHOULD COLD AIR ARRIVE FASTER THAN
FORECAST...MAY SEE A CHANGE TO WINTRY MIX A LITTLE EARLIER.
COLD AIR ADVECTION WILL CONTINUE TUESDAY IN THE NORTHERN CWA AS
FRONT SLOWLY DIGS THROUGH THE CWA. NORTHWESTERN CWA SHOULD FALL
BELOW FREEZING NEAR THE GROUND BY MID-MORNING TUESDAY...AND WITH
LINGERING MID-LEVEL WARM NOSE...WOULD EXPECT PRECIPITATION TO CHANGE
FROM RAIN TO FREEZING RAIN/SLEET. SOUNDINGS ARE ON THE FENCE ON
WHICH WAY TO GO WITH PRECIP TYPE...AND HAVE INCLUDED A MIX OF BOTH.
OBVIOUSLY...IF ONE PHASE DOMINATES...IMPACTS WILL BE SIGNIFICANTLY
DIFFERENT. DID MOVE BACK TIMING ON WINTER STORM WATCH TO BEGIN AT
12Z IN THE FAR NORTHWEST AND 15Z IN THE REMAINING COUNTIES...BUT
WILL LET THE NEXT SHIFT MAKE AN ASSESSMENT ON TEMPERATURE PROFILES
TO DETERMINE POSSIBLE CONVERSION TO WARNING OR ADVISORY. FURTHER
SOUTH...HAVE INCLUDED THUNDERSTORM MENTION IN THE SOUTHEASTERN CWA
AS FRONT IS LIKELY TO ARRIVE DURING THE AFTERNOON WHEN SOME
DESTABILIZATION HAS OCCURRED.
FOLLOWED MODEL SOUNDINGS PRETTY CLOSELY FOR PRECIP TYPE THROUGH
TUESDAY NIGHT...WITH MORE OF A NAM/SREF FLAVOR LEANING TOWARD
CONTINUED ZR/IP. GFS DID LEAN MORE TOWARD SNOW...BUT FOR NOW...HAVE
LEANED TO THE WARMER MID-LEVEL SOLUTION AS THE SLOW-MOVING SYSTEM
CONTINUES TO ALLOW MID-LEVEL WARM AIR ADVECTION AND TROWALING AHEAD
OF IT. MOST OF THE EASTERN HALF OF THE CWA IS PROGGED TO REMAIN
RAIN THROUGH WEDNESDAY...WHILE PRECIPITATION TRANSITIONS TO A MIX
WITH SNOW IN THE NORTHWEST CWA. DELAYED TRANSITION SHOULD HOLD DOWN
AMOUNTS FOR ANY FROZEN PRECIPITATION ACROSS MOST OF THE CWA...AS
PRECIP AMOUNTS ARE PROGGED TO DIMINISH QUITE A BIT ON WEDNESDAY
NIGHT BY THE TIME TEMPS ARE COLD ENOUGH TO ALLOW SNOW ACROSS THE
REST OF THE CWA. STILL...AS WITH ALL PRECIP TYPE ISSUES...THE LINE
BETWEEN PRECIP TYPES IS THIN...AND CONFIDENCE IS ALWAYS ON THE LOW
SIDE FOR THESE TRANSITIONS. AN EARLIER CHANGEOVER WITH COLDER MID-
LEVELS WOULD PRODUCE MORE SNOW ACROSS THE AREA. PRECIPITATION
SHOULD FINALLY BEGIN TO EXIT THE AREA BY THURSDAY...BUT DID LOWER
TEMPS BY SEVERAL DEGREES ON THURSDAY AS THE COLDEST 850MB TEMPS PASS
OVER THE AREA.
MAYES
LONG TERM...THURSDAY NIGHT THROUGH MONDAY
TEMPERATURES SHOULD BEGIN A MODERATING TREND THROUGH LATE WEEK
AND INTO THE WEEKEND AS UPPER-LEVEL FLOW RETURNS TO ZONAL...WITH
TEMPERATURES RETURNING TO NEAR-NORMAL READINGS FOR THE WEEKEND.
MODEL BLENDS CONTINUE TO GIVE A SLIGHT CHANCE TO SMALL CHANCE OF
PRECIPITATION ON SATURDAY NIGHT THROUGH MONDAYNIGHT...BUT
CONFIDENCE IS VERY LOW AS MODELS CONTINUE TO EXHIBIT SIGNIFICANT
RUN TO RUN VARIABILITY IN THE TIMING OR LOCATION OF ANY RAIN.
PRECIPITATION WOULD NOT BE LIKELY DURING ALL OF THOSE
PERIODS...BUT RATHER OVER A NARROWER WINDOW BETWEEN SATURDAY NIGHT
AND MONDAY NIGHT.
MAYES/BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ012-017-030-031.
WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ011-016.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
959 PM EDT MON APR 8 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PREVAIL...IN ADVANCE OF A FRONTAL SYSTEM
THAT WILL AFFECT OUR REGION LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 957 PM MONDAY...
WAVE LOCATED OVER WV PRODUCING AN AREA OF MID TO HIGH CLOUDS WILL
TRAVERSE EASTWARD OVERNIGHT... WITH MOST OF THE ASSOCIATED CLOUD
COVER STAYING NORTH OF THE AREA. GFS LOOKS OVERLY AGGRESSIVE SURGING
NEAR 60 DEGREE DEWPOINTS ACROSS THE AREA OVERNIGHT... 00Z OBS
INDICATE DEWPOINTS NEAR 50... MUCH CLOSER TO THE RUC AND NAM
DEPICTIONS. IN THIS CASE... AS WITH LAST NIGHT... BEST LOW LEVEL
MOISTURE AND CHANCES FOR FOG AND LOW STRATUS WILL BE IN THE COASTAL
PLAIN... WITH A FEW PATCHY AREAS POSSIBLE NORTH AND WEST. OVERNIGHT
TEMPERATURES WILL BE A FEW DEGREES WARMER THAN LAST NIGHT... MID
50S... AS TUESDAY 12Z LOW LEVEL THICKNESSES INCREASE AROUND 9 M OVER
THE SAME TIME MONDAY. -SEC
SENSIBLE WEATHER WILL REMAIN WARM AND DRY ACROSS CENTRAL NC AS
SURFACE HIGH ANCHORED OFFSHORE AND A SLOW MOVING LOW PRESSURE SYSTEM
OVER THE SOUTHERN PLAINS MAINTAINS A WARM LOW LEVEL S-SW FLOW OVER
OUR REGION. WLY FLOW BEGINS TO BACK TONIGHT INTO TUESDAY AS A
MID-UPPER LEVEL RIDGE AMPLIFIES NWD OVER THE SE U.S. THIS ADDITIONAL
WARMING ALOFT WILL LEAD TO VERY WARM SFC TEMPS TUESDAY AFTERNOON.
LOW LEVEL THICKNESSES COUPLED WITH A SOUTH-SOUTHWEST BREEZE SUPPORT
AFTERNOON TEMPS NEAR 80 NW TO THE LOWER 80S ELSEWHERE. MIN TEMPS
55-60 TUESDAY NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 230 PM MONDAY...
WEDNESDAY THROUGH THURSDAY:
MID TO UPPER LEVEL RIDGE AXIS IS EXPECTED TO SLOWLY SHIFT OFFSHORE
DURING THIS TIME FRAME... WITH SURFACE HIGH PRESSURE REMAINING
ANCHORED OFFSHORE AND THE NEXT APPROACHING COLD FRONT REMAINING TO
THE WEST OF THE AREA THROUGH THE PERIOD. THIS WILL RESULT IN
CONTINUED ABOVE NORMAL TEMPS... WITH INCREASING CLOUD COVER AND
PRECIP CHANCES BY LATE THURSDAY. STILL EXPECT THE BEST CHANCES FOR
ANY SHOWERS AND OR STORMS TO REMAIN TO THE WEST OF THE AREA THROUGH
THURSDAY AFTERNOON THOUGH... AS THE DEEP TROUGH ALOFT AND ASSOCIATED
COLD FRONT APPROACHES THE AREA FROM THE WEST. HOWEVER... GIVEN
MODELS HAVE TRENDED TO THE FASTER SIDE OF THE GUIDANCE OVER THE PAST
SEVERAL DAYS WITH THIS SYSTEM... WILL GO WITH SLIGHT CHANCE TO LOW
END CHANCE OF SHOWERS AND STORMS FOR LATE THURSDAY AFTERNOON... WITH
THE BEST CHANCE FOR PRECIP EXPECTED OVERNIGHT.
LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PEAK WEDNESDAY AFTERNOON
CLOSE TO 1400 METERS. THIS WILL RESULT IN A WARM AND PARTLY SUNNY
DAY AFTER THE MORNING FOG AND/OR LOW STRATUS BURNS OFF. EXPECT HIGH
TEMPS TO BE IN THE LOWER TO MID 80S... WITH PERHAPS THE WARMEST
TEMPS ACROSS THE NORTHEAST PIEDMONT NEAR THE NC/VA BORDER. LOWS
THURSDAY MORNING WILL HAVE THE SAME FLAVOR... ABOVE NORMAL. EXPECT
LOWS TO BE AROUND 60. HIGHS ON THURSDAY WILL AGAIN BE WARM.
HOWEVER... WE MAY SEE THE STRATUS AND/OR FOG LINGER LONGER AS LOW
MOISTURE IS EXPECTED TO INCREASE FURTHER IN ADVANCE OF THE NEXT
SYSTEM. THUS... WILL GO WITH HIGHS ON THURSDAY IN THE UPPER 70S NW
TO LOWER 80S ELSEWHERE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 205 PM MONDAY...
THURSDAY NIGHT THROUGH FRIDAY NIGHT:
MEDIUM RANGE MODELS ARE COMING IN BETTER AGREEMENT ON THE NEXT
SYSTEM TO AFFECT THE AREA LATE WEEK... TRENDING TO A BIT FASTER
TIMING. THE GFS (12Z/08TH) AND MOST OF ITS ENSEMBLE MEMBERS
CONTINUES TO BE ON THE FAST SIDE OF THE GUIDANCE WHILE THE LATEST
ECMWF (00Z/08TH) AND ITS RESPECTIVE ENSEMBLE MEMBERS A GOOD 6 TO 9
HOURS SLOWER. WPC HAS ELECTED TO GO WITH BEND BETWEEN THE TWO
OPERATIONAL MODELS... KEEPING IN MIND THE GUIDANCE OVER THE PAST FEW
DAYS HAS TRENDED MORE TO A FASTER MORE PROGRESSIVE SOLUTION. THIS
YIELDS A CLOSED LOW INVOF IA/MO LIFTING NORTHEASTWARD INTO THE GREAT
LAKES REGION THURSDAY EVENING INTO FRIDAY... WITH AN ASSOCIATED
PRIMARY SURFACE LOW TRACKING FROM THE OHIO VALLEY INTO THE GREAT
LAKES AND EVENTUALLY NORTHEAST U.S. BY FRIDAY NIGHT... WITH A
TRAILING COLD FRONT AND ACCOMPANYING BAND OF SHOWERS AND STORMS
CROSSING OUR AREA IN A WEST TO EAST FASHION THURSDAY NIGHT INTO
FRIDAY MORNING/EARLY AFTERNOON. THIS IS A BIT FASTER THAN THE
PREVIOUS FORECAST. FOR NOW WILL SPEED UP THE TIMING A BIT... SHOWING
LIKELY POPS FROM LATE THURSDAY/EARLY FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON. HOWEVER... POPS WILL LIKELY NEED TO BE RAISED AND
FOCUSED OVER A SHORTER TIME FRAME WHEN THE TIMING BECOMES MORE
CLEAR. WRT A SEVERE THREAT... GIVEN THE FASTER TIMING THERE APPEARS
TO BE LESS OF A CHANCE OF SEVERE STORMS... THANKS TO THE OVERNIGHT
INTO MAINLY MORNING TIMING... WITH VERY MINIMAL MLCAPE TO WORK WITH.
HOWEVER... GIVEN DEWPOINTS IN THE MID 60S AND A STRONG LOW LEVEL JET
(WITH 925-850 MB WINDS OF AROUND 40 TO 55 KTS) WE COULD STILL SEE A
FEW STRONG TO SEVERE STORMS ACCOMPANY THE BAND OF SHOWERS AND
STORMS... WITH THE MAIN THREAT FROM DAMAGING WIND GUSTS. MOST OF THE
GUIDANCE HAS THE EFFECTIVE COLD FRONT AND BAND OF SHOWERS AND STORMS
TO THE EAST OF THE RAH CWA BY AROUND 18Z FRIDAY... WITH THE MORE
SIGNIFICANT SECONDARY SHOT OF COLDER/DRY AIR NOT ARRIVING UNTIL
FRIDAY NIGHT WHEN THE SURFACE WINDS SWING AROUND FROM SOUTHWESTERLY
TO NORTHWESTERLY. WE DO NOT EXPECT ANY PRECIP WITH THE SECONDARY
COLD FRONT... JUST AN ACCOMPANYING BAND OF CLOUD COVER (WITH GFS
BUFR SOUNDINGS SHOWING A STRONG SUBSIDENCE INVERSION AROUND 775-800
MB).
TEMPERATURES DURING THIS TIME FRAME WILL BE DRIVEN BY THE ACTUAL
TIME OF THE COLD FRONT. FOR NOW WILL SHOW THE INITIAL COLD FRONT
MOVING INTO THE WESTERN PIEDMONT AROUND 12Z FRIDAY WITH THIS FRONT
TO THE EAST OF THE RAH CWA BY EARLY AFTERNOON. HOWEVER... SOUTHWEST
TO WEST-SOUTHWESTERLY FLOW BEHIND THE INITIAL FRONT AND MOSTLY TO
PARTLY SUNNY SKIES RETURNING BEHIND THE FRONT INITIALLY WILL ALLOW
TEMPS TO WARM QUITE NICELY AGAIN INTO THE MID TO UPPER 70S... AFTER
FRIDAY MORNING LOWS IN THE LOWER TO MID 60S. AS MENTIONED ABOVE THE
SECONDARY COLD FRONT IS EXPECTED TO MOVE THROUGH FRIDAY NIGHT...
WHICH WILL YIELD MUCH COOLER/COLDER LOW TEMPS FOR SATURDAY MORNING.
THUS... EXPECT LOWS BY SATURDAY MORNING WILL RANGE FROM THE MID TO
UPPER 40S... WITH PERHAPS A FEW LOWER 50S IN THE FAR SE.
SATURDAY THROUGH MONDAY:
SURFACE HIGH PRESSURE WILL BUILD ACROSS REGION NEXT WEEKEND... WITH
MOSTLY SUNNY/CLEAR SKIES EXPECTED FOR MOST OF THE WEEKEND... WITH
PERHAPS A BIT MORE CLOUD COVER BY LATE SUNDAY. FORECAST UNCERTAINTY
INCREASES SUNDAY NIGHT INTO MONDAY... AS MEDIUM RANGE MODELS
STRUGGLE WITH BOTH A NORTHERN AND SOUTHERN STREAM SYSTEM. FOR NOW
WILL SHOW CLOUD COVER INCREASING DURING THIS TIME... AND INTRODUCE A
SLIGHT CHANCE OF SHOWERS FOR NEXT MONDAY. EXPECT HIGH TEMPS DURING
THIS PERIOD TO BE NEAR TO SLIGHTLY BELOW NORMAL... GENERALLY IN THE
UPPER 60S TO LOWER 70S.
&&
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 745 PM MONDAY...
AN AREA OF HIGH PRESSURE WILL REMAIN ANCHORED OFFSHORE OF THE SE
U.S. THROUGH THURSDAY. THIS SUGGEST LITTLE DAY-TO-DAY CHANGE IN OUR
SENSIBLE WEATHER WITH THE LOW LEVEL SLY FLOW PRODUCING AREAS OF
STRATUS AND/OR FOG. SREF ENSEMBLE PROBABILITIES INDICATE
A HIGH LIKELIHOOD (60 TO 70 PERCENT)OF IFR TO LIFR CONDITIONS
AT KFAY ONLY...WITH VERY LOW PROBABILITIES AT THE OTHER TAF SITES.
THIS WOULD STRONGLY ADVOCATE USING A PERSISTENCE FORECAST
BASED ON CONDITIONS THIS PAST MORNING.
THE FOG SHOULD BURN OFF WITHIN A COUPLE HOURS OF SUNRISE WHILE THE
STRATUS WILL BE A LITTLE SLOWER TO ERODE/DISSIPATE. IN THEIR
WAKE...EXPECT PARTLY CLOUDY SKIES WITH BASES RANGING 3500-5000FT.
SWLY SURFACE WINDS 10 TO 15 MPH.
LOOKING BEYOND 24 HOURS:
LOW CLOUDS AND FOG WILL BE POSSIBLE ONCE AGAIN WEDNESDAY NIGHT/EARLY
THURSDAY AS A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST.
THE COLD FRONT WILL FINALLY MOVE INTO THE AREA LATE THURSDAY
AND CROSS THE REGION THU NIGHT INTO EARLY FRIDAY. THIS WEATHER
FEATURE WILL TRIGGER SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS. THIS MAY LEAD TO SEVERAL HOURS OF SUB VFR CONDITIONS
THU NIGHT INTO EARLY FRI. A RETURN TO VFR CONDITIONS IS EXPECTED
FRIDAY NIGHT INTO SATURDAY.
&&
.CLIMATE...
IF TEMPERATURES REACH 80 EARLY THIS WEEK...IT WILL BE THE FIRST
80-DEGREE MAXIMUM TEMPERATURE AT KGSO SINCE OCTOBER 24...AND AT KRDU
SINCE OCTOBER 25. KFAY REACHED 80 MORE RECENTLY...WITH AN 83-DEGREE
HIGH ON MARCH 16. OVER THE LAST COUPLE OF YEARS...THE FIRST
80-DEGREE DAYS HAVE BEEN...
KGSO...MARCH 18 2011...AND MARCH 14 2012.
BOTH KRDU AND KFAY...FEBRUARY 27 2011...AND MARCH 1 2012.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...SEC/WSS
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...CBL/WSS
CLIMATE...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1232 PM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 1223 PM CDT SUN APR 7 2013
CLEARED THE FREEZING RAIN ADVISORY ALL BUT JAMES RIVER VALLEY.
UPDATE ISSUED AT 953 AM CDT SUN APR 7 2013
MAINLY CHANGES EARLY THIS MORNING...NOW GETTING SNOW FROM MINOT
AND EAST. THE PRECIPITATION HAS MOVED EAST OF WILLISTON AND
STANLEY. ALSO WARMING TEMPERATURES SOUTH CENTRAL KEEPING THE
PRECIPITATION AS RAIN. CANCELLED THE FREEZING RAIN ADVISORY FOR ALL
BUT MCLEAN COUNTY THROUGH NOON...AND EAST THROUGH HARVEY AND SOUTH
THROUGH THE JAMES RIVER VALLEY THROUGH 7 PM.
UPDATE ISSUED AT 708 AM CDT SUN APR 7 2013
UPDATE THIS MORNING MAINLY FOR TEMPERATURES. LOW PRESSURE OVER
EASTERN MONTANA WITH HIGH PRESSURE OVER EASTERN NORTH DAKOTA
EARLY THIS MORNING WITH A SOUTHEAST FLOW OVER WESTERN NORTH DAKOTA
AND LIGHT WINDS IN THE CENTRAL. EXTENSIVE MVFR-IFR STRATUS ACROSS
ALL OF WESTERN AND CENTRAL NORTH DAKOTA. THIS HAS KEPT
TEMPERATURES FROM FALLING AS FAR AS FORECAST...AND DO NOT EXPECT
TEMPERATURES TO DROP MUCH MORE THIS MORNING. THUS RAISED EARLY
MORNING TEMPERATURES IN THE EAST FROM THE LOW TO MID 20S INTO THE
UPPER 20S. BAND OF PRECIPITATION IS MOVING THROUGH THE WEST AND
INTO CENTRAL NORTH DAKOTA. REPORT OF SOME MIXED PRECIPITATION AT
WILLISTON AND A LITTLE UNDER AN INCH OF SNOW. THE WARMER THAN
EXPECTED TEMPERATURES COMBINED WITH ROAD SURFACE TEMPERATURES AT
OR ABOVE FREEZING IN MANY AREAS...SHOULD HELP TO DIMINISH THE
EFFECTS OF ANY FREEZING RAIN. HOWEVER...EXPECT SECONDARY ROADS...
SIDEWALKS AND PARKING LOTS MAY YET BECOME SLIPPERY. WILL HOLD OFF
ON ANY UPDATES TO THE CURRENT FREEZING RAIN ADVISORY AND SEE IF WE
CAN GET A FEW MORE REPORTS AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST CHALLENGES FOR THE SHORT TERM INCLUDE
PRECIPITATION TIMING AND TYPE. THE 00Z MODEL SUITE IS IN
AGREEMENT...THUS HAVE UTILIZED A BLEND OF GUIDANCE.
LATEST RADAR IMAGERY AT 330 AM CDT IS SHOWING SOME SCATTERED LIGHT
RETURNS ACROSS THE SOUTHWEST....AND MORE WIDESPREAD LIGHT RETURNS
OVER NORTHEASTERN MONTANA ASSOCIATED WITH A WEAK UPPER LEVEL IMPULSE.
HOWEVER...SURFACE OBSERVATIONS HAVE NOT REFLECTED PRECIPITATION
REACHING THE GROUND OVER THE SOUTHWEST. THE 05/06Z RAP SOLUTIONS DO
NOT REFLECT THE LIGHT PRECIPITATION OVER THE NORTHEAST AT THIS
TIME...BUT IT DOES PAINT SOME LIGHT PRECIPITATION ACROSS THE
SOUTHWEST. THE 00Z GFS/ECMWF/NAM ALL SHOW LIGHT PRECIPITATION OVER
NORTHEAST MONTANA AT THIS TIME...AND THUS HAVE UTILIZED A BLEND OF
THE 00Z MODEL GUIDANCE IN ADDITION TO THE 05/06Z RAP GUIDANCE.
PRECIPITATION WILL CONTINUE TO SPREAD EAST WITH TIME...FILLING IN
OVER THE WEST OVER THE NEXT FEW HOURS...AND THEN OVER THE CENTRAL
BY LATER THIS MORNING...AS THE UPPER LEVEL IMPULSE MOVES OVER THE
AREA.
LATEST OBSERVATIONS AT 400 AM CDT SHOW THAT TEMPERATURES SOUTH AND
WEST OF THE MISSOURI RIVER REMAIN ABOVE FREEZING...WHILE NORTH AND
EAST...TEMPERATURES ARE IN THE MID TO UPPER 20S. FOLLOWING THE
COLD FRONTAL PASSAGE YESTERDAY...COLD AIR ADVECTION ALOFT IS
UNDERWAY...WITH A SHALLOW WARM LAYER JUST ABOVE THE SURFACE.
PRECIPITATION WILL START AS FREEZING RAIN...WITH SOME SNOW AND
SLEET MIXED IN ACROSS THE WEST...BUT AS TEMPERATURES WARM ACROSS
THE SOUTHWEST AND SOUTH CENTRAL...A TRANSITION TO RAIN WILL OCCUR.
FOR LOCATIONS ACROSS THE NORTH...WHERE TEMPERATURES ARE CURRENTLY
SUBFREEZING...PRECIPITATION WILL START AS SNOW...BUT AS
TEMPERATURES WARM NEAR THE SURFACE WITH COLDER AIR PRESENT ALOFT...A
TRANSITION TO FREEZING RAIN AND THEN TO A MIX OF FREEZING
RAIN...SLEET...AND SNOW AFTER MIDNIGHT.
EVEN THOUGH THE FORECAST PROCESS HAS LED TO INCREASED MIXED
PRECIPITATION (SNOW...SLEET AND FREEZING RAIN) AND DECREASED
COVERAGE OF FREEZING RAIN...HAVE DECIDED TO CONTINUE THE FREEZING RAIN
ADVISORY AT THIS TIME. WILL CONTINUE TO MONITOR AND MAKE CHANGES
IF WARRANTED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEM IN THE EXTENDED PERIOD WILL MONDAY THROUGH
MONDAY NIGHT...ACTUALLY BEGINNING LATE SUNDAY NIGHT IN THE FAR WEST.
WILL LEAN MORE TOWARD A ECMWF/GEM SOLUTION OVER THE GFS/NAM FOR QPF
DETAILS.
ALTHOUGH THE STRONG UPPER LEVEL SYSTEM IN THE WEST DIVES SOUTH ON
MONDAY...THERE IS STILL A PIECE OF UPPER LEVEL ENERGY THAT MAKES IT
INTO THE NORTHERN PLAINS. DETERMINISTIC MODELS ARE IN REASONABLE
AGREEMENT IN BRINGING THIS INTO THE LOCAL AREA. ALTHOUGH RATHER
SIGNIFICANT DIFFERENCES IN THE RESULTING PLACEMENT OF THE QPF AS THE
WAVE INTERACT WITH A TIGHTENING BAROCLINIC ZONE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE NAM/GFS ARE FARTHER NORTH WITH THE QPF
THAN THE GEM/ECMWF...ALTHOUGH THE 00 UTC SUNDAY ECMWF HAS COME A
LITTLE FARTHER NORTH THAN PREVIOUS RUNS. LOOKING AT GFS BUFKIT
SOUNDINGS...THERE DOES APPEAR TO BE A 3 TO 6 HOUR PERIOD WITH STRONG
OMEGA OVER WITHIN THE SNOW GROWTH ZONE IN THE WEST CENTRAL AND
SOUTHWEST...WHICH SHOULD YIELD SOME DECENT SNOW AMOUNTS. THIS AREA
EXTENDS EAST ACROSS CENTRAL NORTH DAKOTA DURING THE DAY MONDAY BUT
STRONG HIGH PRESSURE DROPPING SOUTH FROM CANADA WILL INHIBIT FG
FORCING LATER IN THE DAY. THIS SHOULD REDUCE SNOW AMOUNTS AS THE
WAVE MOVES EASTWARD INTO CENTRAL AND EASTERN NORTH DAKOTA.
A COMBINATION OF HPC SNOW AMOUNTS WITH MODEL QPF YIELDS 3 TO 5
INCHES OF SNOW OVER MUCH OF WEST CENTRAL AND SOUTHWEST NORTH
DAKOTA...WITH 2 TO 3 INCHES EXTENDING EAST INTO GRANT AND MORTON
COUNTIES. SNOW TOTALS TAPER TO AN INCH OR TWO EAST OF THE MISSOURI
RIVER. THE NORTHERN EXTENT OF THE HEAVIER SNOW REMAINS ALONG AND
SOUTH OF LAKE SAKAKAWEA...WEST OF THE MISSOURI...THEN ALONG AND
SOUTH OF THE I94 CORRIDOR EAST OF THE MISSOURI. ALTHOUGH SIGNIFICANT
DIFFERENCES STILL REMAIN...FEEL CONFIDENT ENOUGH THAT A WINTER
WEATHER ADVISORY IS WARRANTED OVER THE SOUTHWEST AND WEST CENTRAL.
CONFIDENCE WANES AS YOU GO EAST...BUT WILL EXTEND THE ADVISORY
EAST TO COVER MOST OF THE AREA WEST OF THE MISSOURI AND SOUTH OF THE
LAKE.
AT THIS TIME IT APPEARS THAT THERE SHOULD BE A QUICK TRANSITION FROM
RAIN TO SNOW AS COLD AIR RUSHES SOUTH LATE SUNDAY NIGHT. HOWEVER...A
PERIOD OF MIXED PRECIPITATION CANNOT BE RULED OUT BEFORE THE COLD
AIR IS FIRMLY ENTRENCHED OVER THE AREA BY MONDAY MORNING. AS THE
CANADIAN HIGH DROPS SOUTH WE SHOULD SEE A NICE ISALLOBARIC COMPONENT
MOVE ACROSS THE WEST AND SOUTH CENTRAL ON MONDAY RESULTING IN
SUSTAINED WINDS OF 15 TO 20 MPH AND GUST OF 25 TO 30 MPH. ALTHOUGH
THERE IS NO LOOSE SNOW...WINDS WILL BE STRONG ENOUGH FOR SOME
BLOWING SNOW AS IT FALLS. THUS WILL MAKE THE ADVISORY FOR SNOW AND
BLOWING SNOW...LASTING FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT.
AS THE MAIN UPPER LOW MOVES ONTO THE PLAINS ON TUESDAY...COLD HIGH
PRESSURE OVER SASKATCHEWAN INTO NORTH DAKOTA SHOULD KEEP THE
NORTHERN EXTEND OF THE SYSTEM RIGHT ALONG THE SOUTH DAKOTA BORDER
WITH ANY SIGNIFICANT PRECIPITATION REMAINING SOUTH OF THE STATE.
THEN AS THE SYSTEM BEGINS TO EJECT NORTHEAST TUESDAY NIGHT THE
PRECIPITATION SHIELD TRIES TO PUSH A BIT FARTHER NORTH AND MAY CLIP
THE FAR SOUTH AND SOUTHEAST COUNTIES WITH LIGHT SNOW. AT THIS TIME
WE ARE KEEPING HIGH CHANCE POPS ALONG THE SOUTH DAKOTA
BORDER...TAPERING TO SLIGHT CHANCE POPS AROUND INTERSTATE 94. THE
NORTHERN HALF OF THE CWA IS EXPECTED TO REMAIN DRY TUESDAY AND
TUESDAY NIGHT. TEMPERATURES DURING THIS PERIOD...MONDAY THROUGH
WEDNESDAY...WILL BE BELOW NORMAL WITH 20S NORTH TO 30S SOUTH. WE DO
SEE SOME SLIGHT WARMING BY AROUND THURSDAY AS THE SYSTEM EXITS TO
OUR EAST...BUT A PROGRESSIVE NORTHWEST FLOW WILL BRING A SERIES OF
UPPER LEVEL WAVES INTO THE AREA LATE IN THE WEEK KEEPING OUR WEATHER
UNSETTLED WITH TEMPERATURES NEAR OR BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED
AT 1225 PM CDT SUN APR 7 2013
A WARM FRONT EXTENDED ACROSS SOUTHWEST NORTH DAKOTA. MAIN HAZARD
TO AVIATION WILL BE FREEZING RAIN/SLEET AT KJMS THROUGH 21Z.
OTHERWISE MVFR FROM KMOT-KJMS. VFR WILL EXTEND FROM KISN-KDIK-
KBIS. ANOTHER ROUND OF WINTER WEATHER WILL MOVE INTO WESTERN NORTH
DAKOTA SUNDAY NIGHT AND MONDAY. MAIN IMPACTS TO AVIATION WILL
BE IFR CONDITIONS SPREADING INTO KDIK AFTER 09Z. MVFR RETURNING TO
KISN-KMOT-KBIS-KJMS AFTER 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ MONDAY TO 1
AM CDT /MIDNIGHT MDT/ TUESDAY FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ022-
023-037-048-051.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
958 AM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 953 AM CDT SUN APR 7 2013
MAINLY CHANGES EARLY THIS MORNING...NOW GETTING SNOW FROM MINOT
AND EAST. THE PRECIPITATION HAS MOVED EAST OF WILLISTON AND
STANLEY. ALSO WARMING TEMPERATURES SOUTH CENTRAL KEEPING THE
PRECIPITATION AS RAIN. CANCELLED THE FREEZING RAIN ADVISORY FOR ALL
BUT MCLEAN COUNTY THROUGH NOON...AND EAST THROUGH HARVEY AND SOUTH
THROUGH THE JAMES RIVER VALLEY THROUGH 7 PM.
UPDATE ISSUED AT 708 AM CDT SUN APR 7 2013
UPDATE THIS MORNING MAINLY FOR TEMPERATURES. LOW PRESSURE OVER
EASTERN MONTANA WITH HIGH PRESSURE OVER EASTERN NORTH DAKOTA
EARLY THIS MORNING WITH A SOUTHEAST FLOW OVER WESTERN NORTH DAKOTA
AND LIGHT WINDS IN THE CENTRAL. EXTENSIVE MVFR-IFR STRATUS ACROSS
ALL OF WESTERN AND CENTRAL NORTH DAKOTA. THIS HAS KEPT
TEMPERATURES FROM FALLING AS FAR AS FORECAST...AND DO NOT EXPECT
TEMPERATURES TO DROP MUCH MORE THIS MORNING. THUS RAISED EARLY
MORNING TEMPERATURES IN THE EAST FROM THE LOW TO MID 20S INTO THE
UPPER 20S. BAND OF PRECIPITATION IS MOVING THROUGH THE WEST AND
INTO CENTRAL NORTH DAKOTA. REPORT OF SOME MIXED PRECIPITATION AT
WILLISTON AND A LITTLE UNDER AN INCH OF SNOW. THE WARMER THAN
EXPECTED TEMPERATURES COMBINED WITH ROAD SURFACE TEMPERATURES AT
OR ABOVE FREEZING IN MANY AREAS...SHOULD HELP TO DIMINISH THE
EFFECTS OF ANY FREEZING RAIN. HOWEVER...EXPECT SECONDARY ROADS...
SIDEWALKS AND PARKING LOTS MAY YET BECOME SLIPPERY. WILL HOLD OFF
ON ANY UPDATES TO THE CURRENT FREEZING RAIN ADVISORY AND SEE IF WE
CAN GET A FEW MORE REPORTS AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST CHALLENGES FOR THE SHORT TERM INCLUDE
PRECIPITATION TIMING AND TYPE. THE 00Z MODEL SUITE IS IN
AGREEMENT...THUS HAVE UTILIZED A BLEND OF GUIDANCE.
LATEST RADAR IMAGERY AT 330 AM CDT IS SHOWING SOME SCATTERED LIGHT
RETURNS ACROSS THE SOUTHWEST....AND MORE WIDESPREAD LIGHT RETURNS
OVER NORTHEASTERN MONTANA ASSOCIATED WITH A WEAK UPPER LEVEL IMPULSE.
HOWEVER...SURFACE OBSERVATIONS HAVE NOT REFLECTED PRECIPITATION
REACHING THE GROUND OVER THE SOUTHWEST. THE 05/06Z RAP SOLUTIONS DO
NOT REFLECT THE LIGHT PRECIPITATION OVER THE NORTHEAST AT THIS
TIME...BUT IT DOES PAINT SOME LIGHT PRECIPITATION ACROSS THE
SOUTHWEST. THE 00Z GFS/ECMWF/NAM ALL SHOW LIGHT PRECIPITATION OVER
NORTHEAST MONTANA AT THIS TIME...AND THUS HAVE UTILIZED A BLEND OF
THE 00Z MODEL GUIDANCE IN ADDITION TO THE 05/06Z RAP GUIDANCE.
PRECIPITATION WILL CONTINUE TO SPREAD EAST WITH TIME...FILLING IN
OVER THE WEST OVER THE NEXT FEW HOURS...AND THEN OVER THE CENTRAL
BY LATER THIS MORNING...AS THE UPPER LEVEL IMPULSE MOVES OVER THE
AREA.
LATEST OBSERVATIONS AT 400 AM CDT SHOW THAT TEMPERATURES SOUTH AND
WEST OF THE MISSOURI RIVER REMAIN ABOVE FREEZING...WHILE NORTH AND
EAST...TEMPERATURES ARE IN THE MID TO UPPER 20S. FOLLOWING THE
COLD FRONTAL PASSAGE YESTERDAY...COLD AIR ADVECTION ALOFT IS
UNDERWAY...WITH A SHALLOW WARM LAYER JUST ABOVE THE SURFACE.
PRECIPITATION WILL START AS FREEZING RAIN...WITH SOME SNOW AND
SLEET MIXED IN ACROSS THE WEST...BUT AS TEMPERATURES WARM ACROSS
THE SOUTHWEST AND SOUTH CENTRAL...A TRANSITION TO RAIN WILL OCCUR.
FOR LOCATIONS ACROSS THE NORTH...WHERE TEMPERATURES ARE CURRENTLY
SUBFREEZING...PRECIPITATION WILL START AS SNOW...BUT AS
TEMPERATURES WARM NEAR THE SURFACE WITH COLDER AIR PRESENT ALOFT...A
TRANSITION TO FREEZING RAIN AND THEN TO A MIX OF FREEZING
RAIN...SLEET...AND SNOW AFTER MIDNIGHT.
EVEN THOUGH THE FORECAST PROCESS HAS LED TO INCREASED MIXED
PRECIPITATION (SNOW...SLEET AND FREEZING RAIN) AND DECREASED
COVERAGE OF FREEZING RAIN...HAVE DECIDED TO CONTINUE THE FREEZING RAIN
ADVISORY AT THIS TIME. WILL CONTINUE TO MONITOR AND MAKE CHANGES
IF WARRANTED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEM IN THE EXTENDED PERIOD WILL MONDAY THROUGH
MONDAY NIGHT...ACTUALLY BEGINNING LATE SUNDAY NIGHT IN THE FAR WEST.
WILL LEAN MORE TOWARD A ECMWF/GEM SOLUTION OVER THE GFS/NAM FOR QPF
DETAILS.
ALTHOUGH THE STRONG UPPER LEVEL SYSTEM IN THE WEST DIVES SOUTH ON
MONDAY...THERE IS STILL A PIECE OF UPPER LEVEL ENERGY THAT MAKES IT
INTO THE NORTHERN PLAINS. DETERMINISTIC MODELS ARE IN REASONABLE
AGREEMENT IN BRINGING THIS INTO THE LOCAL AREA. ALTHOUGH RATHER
SIGNIFICANT DIFFERENCES IN THE RESULTING PLACEMENT OF THE QPF AS THE
WAVE INTERACT WITH A TIGHTENING BAROCLINIC ZONE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE NAM/GFS ARE FARTHER NORTH WITH THE QPF
THAN THE GEM/ECMWF...ALTHOUGH THE 00 UTC SUNDAY ECMWF HAS COME A
LITTLE FARTHER NORTH THAN PREVIOUS RUNS. LOOKING AT GFS BUFKIT
SOUNDINGS...THERE DOES APPEAR TO BE A 3 TO 6 HOUR PERIOD WITH STRONG
OMEGA OVER WITHIN THE SNOW GROWTH ZONE IN THE WEST CENTRAL AND
SOUTHWEST...WHICH SHOULD YIELD SOME DECENT SNOW AMOUNTS. THIS AREA
EXTENDS EAST ACROSS CENTRAL NORTH DAKOTA DURING THE DAY MONDAY BUT
STRONG HIGH PRESSURE DROPPING SOUTH FROM CANADA WILL INHIBIT FG
FORCING LATER IN THE DAY. THIS SHOULD REDUCE SNOW AMOUNTS AS THE
WAVE MOVES EASTWARD INTO CENTRAL AND EASTERN NORTH DAKOTA.
A COMBINATION OF HPC SNOW AMOUNTS WITH MODEL QPF YIELDS 3 TO 5
INCHES OF SNOW OVER MUCH OF WEST CENTRAL AND SOUTHWEST NORTH
DAKOTA...WITH 2 TO 3 INCHES EXTENDING EAST INTO GRANT AND MORTON
COUNTIES. SNOW TOTALS TAPER TO AN INCH OR TWO EAST OF THE MISSOURI
RIVER. THE NORTHERN EXTENT OF THE HEAVIER SNOW REMAINS ALONG AND
SOUTH OF LAKE SAKAKAWEA...WEST OF THE MISSOURI...THEN ALONG AND
SOUTH OF THE I94 CORRIDOR EAST OF THE MISSOURI. ALTHOUGH SIGNIFICANT
DIFFERENCES STILL REMAIN...FEEL CONFIDENT ENOUGH THAT A WINTER
WEATHER ADVISORY IS WARRANTED OVER THE SOUTHWEST AND WEST CENTRAL.
CONFIDENCE WANES AS YOU GO EAST...BUT WILL EXTEND THE ADVISORY
EAST TO COVER MOST OF THE AREA WEST OF THE MISSOURI AND SOUTH OF THE
LAKE.
AT THIS TIME IT APPEARS THAT THERE SHOULD BE A QUICK TRANSITION FROM
RAIN TO SNOW AS COLD AIR RUSHES SOUTH LATE SUNDAY NIGHT. HOWEVER...A
PERIOD OF MIXED PRECIPITATION CANNOT BE RULED OUT BEFORE THE COLD
AIR IS FIRMLY ENTRENCHED OVER THE AREA BY MONDAY MORNING. AS THE
CANADIAN HIGH DROPS SOUTH WE SHOULD SEE A NICE ISALLOBARIC COMPONENT
MOVE ACROSS THE WEST AND SOUTH CENTRAL ON MONDAY RESULTING IN
SUSTAINED WINDS OF 15 TO 20 MPH AND GUST OF 25 TO 30 MPH. ALTHOUGH
THERE IS NO LOOSE SNOW...WINDS WILL BE STRONG ENOUGH FOR SOME
BLOWING SNOW AS IT FALLS. THUS WILL MAKE THE ADVISORY FOR SNOW AND
BLOWING SNOW...LASTING FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT.
AS THE MAIN UPPER LOW MOVES ONTO THE PLAINS ON TUESDAY...COLD HIGH
PRESSURE OVER SASKATCHEWAN INTO NORTH DAKOTA SHOULD KEEP THE
NORTHERN EXTEND OF THE SYSTEM RIGHT ALONG THE SOUTH DAKOTA BORDER
WITH ANY SIGNIFICANT PRECIPITATION REMAINING SOUTH OF THE STATE.
THEN AS THE SYSTEM BEGINS TO EJECT NORTHEAST TUESDAY NIGHT THE
PRECIPITATION SHIELD TRIES TO PUSH A BIT FARTHER NORTH AND MAY CLIP
THE FAR SOUTH AND SOUTHEAST COUNTIES WITH LIGHT SNOW. AT THIS TIME
WE ARE KEEPING HIGH CHANCE POPS ALONG THE SOUTH DAKOTA
BORDER...TAPERING TO SLIGHT CHANCE POPS AROUND INTERSTATE 94. THE
NORTHERN HALF OF THE CWA IS EXPECTED TO REMAIN DRY TUESDAY AND
TUESDAY NIGHT. TEMPERATURES DURING THIS PERIOD...MONDAY THROUGH
WEDNESDAY...WILL BE BELOW NORMAL WITH 20S NORTH TO 30S SOUTH. WE DO
SEE SOME SLIGHT WARMING BY AROUND THURSDAY AS THE SYSTEM EXITS TO
OUR EAST...BUT A PROGRESSIVE NORTHWEST FLOW WILL BRING A SERIES OF
UPPER LEVEL WAVES INTO THE AREA LATE IN THE WEEK KEEPING OUR WEATHER
UNSETTLED WITH TEMPERATURES NEAR OR BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 7 2013
WIDESPREAD STRATUS REMAINS OVER THE REGION THIS MORNING. THE MAIN
HAZARDS TO AVIATION INCLUDE THE MVFR/IFR CONDITIONS ASSOCIATED
WITH THE STRATUS...AND FREEZING RAIN AND MIXED PRECIPITATION
EXPECTED TO MOVE THROUGH SOUTH CENTRAL NORTH DAKOTA THROUGHOUT
THE DAY. TEMPERATURES WARMER AT KDIK/KBIS...LIGHT RAIN THERE. A BRIEF
BREAK IN PRECIPITATION WILL BE POSSIBLE LATER THIS
AFTERNOON...BEFORE THE NEXT ROUND OF LIGHT RAIN AND MIXED
PRECIPITATION ARRIVES SUNDAY EVENING AND MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ MONDAY TO 1
AM CDT /MIDNIGHT MDT/ TUESDAY FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ022-
023-036-037-047-048-050-051.
FREEZING RAIN ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NDZ021.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
708 AM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 708 AM CDT SUN APR 7 2013
UPDATE THIS MORNING MAINLY FOR TEMPERATURES. LOW PRESSURE OVER
EASTERN MONTANA WITH HIGH PRESSURE OVER EASTERN NORTH DAKOTA
EARLY THIS MORNING WITH A SOUTHEAST FLOW OVER WESTERN NORTH DAKOTA
AND LIGHT WINDS IN THE CENTRAL. EXTENSIVE MVFR-IFR STRATUS ACROSS
ALL OF WESTERN AND CENTRAL NORTH DAKOTA. THIS HAS KEPT
TEMPERATURES FROM FALLING AS FAR AS FORECAST...AND DO NOT EXPECT
TEMPERATURES TO DROP MUCH MORE THIS MORNING. THUS RAISED EARLY
MORNING TEMPERATURES IN THE EAST FROM THE LOW TO MID 20S INTO THE
UPPER 20S. BAND OF PRECIPITATION IS MOVING THROUGH THE WEST AND
INTO CENTRAL NORTH DAKOTA. REPORT OF SOME MIXED PRECIPITATION AT
WILLISTON AND A LITTLE UNDER AN INCH OF SNOW. THE WARMER THAN
EXPECTED TEMPERATURES COMBINED WITH ROAD SURFACE TEMPERATURES AT
OR ABOVE FREEZING IN MANY AREAS...SHOULD HELP TO DIMINISH THE
EFFECTS OF ANY FREEZING RAIN. HOWEVER...EXPECT SECONDARY ROADS...
SIDEWALKS AND PARKING LOTS MAY YET BECOME SLIPPERY. WILL HOLD OFF
ON ANY UPDATES TO THE CURRENT FREEZING RAIN ADVISORY AND SEE IF WE
CAN GET A FEW MORE REPORTS AFTER SUNRISE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST CHALLENGES FOR THE SHORT TERM INCLUDE
PRECIPITATION TIMING AND TYPE. THE 00Z MODEL SUITE IS IN
AGREEMENT...THUS HAVE UTILIZED A BLEND OF GUIDANCE.
LATEST RADAR IMAGERY AT 330 AM CDT IS SHOWING SOME SCATTERED LIGHT
RETURNS ACROSS THE SOUTHWEST....AND MORE WIDESPREAD LIGHT RETURNS
OVER NORTHEASTERN MONTANA ASSOCIATED WITH A WEAK UPPER LEVEL IMPULSE.
HOWEVER...SURFACE OBSERVATIONS HAVE NOT REFLECTED PRECIPITATION
REACHING THE GROUND OVER THE SOUTHWEST. THE 05/06Z RAP SOLUTIONS DO
NOT REFLECT THE LIGHT PRECIPITATION OVER THE NORTHEAST AT THIS
TIME...BUT IT DOES PAINT SOME LIGHT PRECIPITATION ACROSS THE
SOUTHWEST. THE 00Z GFS/ECMWF/NAM ALL SHOW LIGHT PRECIPITATION OVER
NORTHEAST MONTANA AT THIS TIME...AND THUS HAVE UTILIZED A BLEND OF
THE 00Z MODEL GUIDANCE IN ADDITION TO THE 05/06Z RAP GUIDANCE.
PRECIPITATION WILL CONTINUE TO SPREAD EAST WITH TIME...FILLING IN
OVER THE WEST OVER THE NEXT FEW HOURS...AND THEN OVER THE CENTRAL
BY LATER THIS MORNING...AS THE UPPER LEVEL IMPULSE MOVES OVER THE
AREA.
LATEST OBSERVATIONS AT 400 AM CDT SHOW THAT TEMPERATURES SOUTH AND
WEST OF THE MISSOURI RIVER REMAIN ABOVE FREEZING...WHILE NORTH AND
EAST...TEMPERATURES ARE IN THE MID TO UPPER 20S. FOLLOWING THE
COLD FRONTAL PASSAGE YESTERDAY...COLD AIR ADVECTION ALOFT IS
UNDERWAY...WITH A SHALLOW WARM LAYER JUST ABOVE THE SURFACE.
PRECIPITATION WILL START AS FREEZING RAIN...WITH SOME SNOW AND
SLEET MIXED IN ACROSS THE WEST...BUT AS TEMPERATURES WARM ACROSS
THE SOUTHWEST AND SOUTH CENTRAL...A TRANSITION TO RAIN WILL OCCUR.
FOR LOCATIONS ACROSS THE NORTH...WHERE TEMPERATURES ARE CURRENTLY
SUBFREEZING...PRECIPITATION WILL START AS SNOW...BUT AS
TEMPERATURES WARM NEAR THE SURFACE WITH COLDER AIR PRESENT ALOFT...A
TRANSITION TO FREEZING RAIN AND THEN TO A MIX OF FREEZING
RAIN...SLEET...AND SNOW AFTER MIDNIGHT.
EVEN THOUGH THE FORECAST PROCESS HAS LED TO INCREASED MIXED
PRECIPITATION (SNOW...SLEET AND FREEZING RAIN) AND DECREASED
COVERAGE OF FREEZING RAIN...HAVE DECIDED TO CONTINUE THE FREEZING RAIN
ADVISORY AT THIS TIME. WILL CONTINUE TO MONITOR AND MAKE CHANGES
IF WARRANTED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEM IN THE EXTENDED PERIOD WILL MONDAY THROUGH
MONDAY NIGHT...ACTUALLY BEGINNING LATE SUNDAY NIGHT IN THE FAR WEST.
WILL LEAN MORE TOWARD A ECMWF/GEM SOLUTION OVER THE GFS/NAM FOR QPF
DETAILS.
ALTHOUGH THE STRONG UPPER LEVEL SYSTEM IN THE WEST DIVES SOUTH ON
MONDAY...THERE IS STILL A PIECE OF UPPER LEVEL ENERGY THAT MAKES IT
INTO THE NORTHERN PLAINS. DETERMINISTIC MODELS ARE IN REASONABLE
AGREEMENT IN BRINGING THIS INTO THE LOCAL AREA. ALTHOUGH RATHER
SIGNIFICANT DIFFERENCES IN THE RESULTING PLACEMENT OF THE QPF AS THE
WAVE INTERACT WITH A TIGHTENING BAROCLINIC ZONE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE NAM/GFS ARE FARTHER NORTH WITH THE QPF
THAN THE GEM/ECMWF...ALTHOUGH THE 00 UTC SUNDAY ECMWF HAS COME A
LITTLE FARTHER NORTH THAN PREVIOUS RUNS. LOOKING AT GFS BUFKIT
SOUNDINGS...THERE DOES APPEAR TO BE A 3 TO 6 HOUR PERIOD WITH STRONG
OMEGA OVER WITHIN THE SNOW GROWTH ZONE IN THE WEST CENTRAL AND
SOUTHWEST...WHICH SHOULD YIELD SOME DECENT SNOW AMOUNTS. THIS AREA
EXTENDS EAST ACROSS CENTRAL NORTH DAKOTA DURING THE DAY MONDAY BUT
STRONG HIGH PRESSURE DROPPING SOUTH FROM CANADA WILL INHIBIT FG
FORCING LATER IN THE DAY. THIS SHOULD REDUCE SNOW AMOUNTS AS THE
WAVE MOVES EASTWARD INTO CENTRAL AND EASTERN NORTH DAKOTA.
A COMBINATION OF HPC SNOW AMOUNTS WITH MODEL QPF YIELDS 3 TO 5
INCHES OF SNOW OVER MUCH OF WEST CENTRAL AND SOUTHWEST NORTH
DAKOTA...WITH 2 TO 3 INCHES EXTENDING EAST INTO GRANT AND MORTON
COUNTIES. SNOW TOTALS TAPER TO AN INCH OR TWO EAST OF THE MISSOURI
RIVER. THE NORTHERN EXTENT OF THE HEAVIER SNOW REMAINS ALONG AND
SOUTH OF LAKE SAKAKAWEA...WEST OF THE MISSOURI...THEN ALONG AND
SOUTH OF THE I94 CORRIDOR EAST OF THE MISSOURI. ALTHOUGH SIGNIFICANT
DIFFERENCES STILL REMAIN...FEEL CONFIDENT ENOUGH THAT A WINTER
WEATHER ADVISORY IS WARRANTED OVER THE SOUTHWEST AND WEST CENTRAL.
CONFIDENCE WANES AS YOU GO EAST...BUT WILL EXTEND THE ADVISORY
EAST TO COVER MOST OF THE AREA WEST OF THE MISSOURI AND SOUTH OF THE
LAKE.
AT THIS TIME IT APPEARS THAT THERE SHOULD BE A QUICK TRANSITION FROM
RAIN TO SNOW AS COLD AIR RUSHES SOUTH LATE SUNDAY NIGHT. HOWEVER...A
PERIOD OF MIXED PRECIPITATION CANNOT BE RULED OUT BEFORE THE COLD
AIR IS FIRMLY ENTRENCHED OVER THE AREA BY MONDAY MORNING. AS THE
CANADIAN HIGH DROPS SOUTH WE SHOULD SEE A NICE ISALLOBARIC COMPONENT
MOVE ACROSS THE WEST AND SOUTH CENTRAL ON MONDAY RESULTING IN
SUSTAINED WINDS OF 15 TO 20 MPH AND GUST OF 25 TO 30 MPH. ALTHOUGH
THERE IS NO LOOSE SNOW...WINDS WILL BE STRONG ENOUGH FOR SOME
BLOWING SNOW AS IT FALLS. THUS WILL MAKE THE ADVISORY FOR SNOW AND
BLOWING SNOW...LASTING FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT.
AS THE MAIN UPPER LOW MOVES ONTO THE PLAINS ON TUESDAY...COLD HIGH
PRESSURE OVER SASKATCHEWAN INTO NORTH DAKOTA SHOULD KEEP THE
NORTHERN EXTEND OF THE SYSTEM RIGHT ALONG THE SOUTH DAKOTA BORDER
WITH ANY SIGNIFICANT PRECIPITATION REMAINING SOUTH OF THE STATE.
THEN AS THE SYSTEM BEGINS TO EJECT NORTHEAST TUESDAY NIGHT THE
PRECIPITATION SHIELD TRIES TO PUSH A BIT FARTHER NORTH AND MAY CLIP
THE FAR SOUTH AND SOUTHEAST COUNTIES WITH LIGHT SNOW. AT THIS TIME
WE ARE KEEPING HIGH CHANCE POPS ALONG THE SOUTH DAKOTA
BORDER...TAPERING TO SLIGHT CHANCE POPS AROUND INTERSTATE 94. THE
NORTHERN HALF OF THE CWA IS EXPECTED TO REMAIN DRY TUESDAY AND
TUESDAY NIGHT. TEMPERATURES DURING THIS PERIOD...MONDAY THROUGH
WEDNESDAY...WILL BE BELOW NORMAL WITH 20S NORTH TO 30S SOUTH. WE DO
SEE SOME SLIGHT WARMING BY AROUND THURSDAY AS THE SYSTEM EXITS TO
OUR EAST...BUT A PROGRESSIVE NORTHWEST FLOW WILL BRING A SERIES OF
UPPER LEVEL WAVES INTO THE AREA LATE IN THE WEEK KEEPING OUR WEATHER
UNSETTLED WITH TEMPERATURES NEAR OR BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 708 AM CDT SUN APR 7 2013
WIDESPREAD STRATUS REMAINS OVER THE REGION THIS MORNING. THE MAIN
HAZARDS TO AVIATION INCLUDE THE MVFR/IFR CONDITIONS ASSOCIATED
WITH THE STRATUS...AND FREEZING RAIN AND MIXED PRECIPITATION
EXPECTED TO MOVE FROM WESTERN...INTO CENTRAL NORTH DAKOTA
THROUGHOUT THE DAY. AS TEMPERATURES WARM AT KDIK...LIGHT
FREEZING RAIN WILL GIVE WAY TO LIGHT RAIN. A BRIEF BREAK IN
PRECIPITATION WILL BE POSSIBLE LATER THIS AFTERNOON...BEFORE THE
NEXT ROUND OF LIGHT RAIN AND MIXED PRECIPITATION ARRIVES SUNDAY
EVENING AND MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ MONDAY TO 1
AM CDT /MIDNIGHT MDT/ TUESDAY FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NDZ002-
010-019>021-034-035-046.
FREEZING RAIN ADVISORY UNTIL 11 AM CDT /10 AM MDT/ THIS MORNING
FOR NDZ001-009-017-018-033-041.
FREEZING RAIN ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS
EVENING FOR NDZ003-011-012-022-023-036-037-047-048-050-051.
&&
$$
UPDATE...TWH
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
429 AM CDT SUN APR 7 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST CHALLENGES FOR THE SHORT TERM INCLUDE
PRECIPITATION TIMING AND TYPE. THE 00Z MODEL SUITE IS IN
AGREEMENT...THUS HAVE UTILIZED A BLEND OF GUIDANCE.
LATEST RADAR IMAGERY AT 330 AM CDT IS SHOWING SOME SCATTERED LIGHT
RETURNS ACROSS THE SOUTHWEST....AND MORE WIDESPREAD LIGHT RETURNS
OVER NORTHEASTERN MONTANA ASSOCIATED WITH A WEAK UPPER LEVEL IMPULSE.
HOWEVER...SURFACE OBSERVATIONS HAVE NOT REFLECTED PRECIPITATION
REACHING THE GROUND OVER THE SOUTHWEST. THE 05/06Z RAP SOLUTIONS DO
NOT REFLECT THE LIGHT PRECIPITATION OVER THE NORTHEAST AT THIS
TIME...BUT IT DOES PAINT SOME LIGHT PRECIPITATION ACROSS THE
SOUTHWEST. THE 00Z GFS/ECMWF/NAM ALL SHOW LIGHT PRECIPITATION OVER
NORTHEAST MONTANA AT THIS TIME...AND THUS HAVE UTILIZED A BLEND OF
THE 00Z MODEL GUIDANCE IN ADDITION TO THE 05/06Z RAP GUIDANCE.
PRECIPITATION WILL CONTINUE TO SPREAD EAST WITH TIME...FILLING IN
OVER THE WEST OVER THE NEXT FEW HOURS...AND THEN OVER THE CENTRAL
BY LATER THIS MORNING...AS THE UPPER LEVEL IMPULSE MOVES OVER THE
AREA.
LATEST OBSERVATIONS AT 400 AM CDT SHOW THAT TEMPERATURES SOUTH AND
WEST OF THE MISSOURI RIVER REMAIN ABOVE FREEZING...WHILE NORTH AND
EAST...TEMPERATURES ARE IN THE MID TO UPPER 20S. FOLLOWING THE
COLD FRONTAL PASSAGE YESTERDAY...COLD AIR ADVECTION ALOFT IS
UNDERWAY...WITH A SHALLOW WARM LAYER JUST ABOVE THE SURFACE.
PRECIPITATION WILL START AS FREEZING RAIN...WITH SOME SNOW AND
SLEET MIXED IN ACROSS THE WEST...BUT AS TEMPERATURES WARM ACROSS
THE SOUTHWEST AND SOUTH CENTRAL...A TRANSITION TO RAIN WILL OCCUR.
FOR LOCATIONS ACROSS THE NORTH...WHERE TEMPERATURES ARE CURRENTLY
SUBFREEZING...PRECIPITATION WILL START AS SNOW...BUT AS
TEMPERATURES WARM NEAR THE SURFACE WITH COLDER AIR PRESENT ALOFT...A
TRANSITION TO FREEZING RAIN AND THEN TO A MIX OF FREEZING
RAIN...SLEET...AND SNOW AFTER MIDNIGHT.
EVEN THOUGH THE FORECAST PROCESS HAS LED TO INCREASED MIXED
PRECIPITATION (SNOW...SLEET AND FREEZING RAIN) AND DECREASED
COVERAGE OF FREEZING RAIN...HAVE DECIDED TO CONTINUE THE FREEZING RAIN
ADVISORY AT THIS TIME. WILL CONTINUE TO MONITOR AND MAKE CHANGES
IF WARRANTED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 329 AM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEM IN THE EXTENDED PERIOD WILL MONDAY THROUGH
MONDAY NIGHT...ACTUALLY BEGINNING LATE SUNDAY NIGHT IN THE FAR WEST.
WILL LEAN MORE TOWARD A ECMWF/GEM SOLUTION OVER THE GFS/NAM FOR QPF
DETAILS.
ALTHOUGH THE STRONG UPPER LEVEL SYSTEM IN THE WEST DIVES SOUTH ON
MONDAY...THERE IS STILL A PIECE OF UPPER LEVEL ENERGY THAT MAKES IT
INTO THE NORTHERN PLAINS. DETERMINISTIC MODELS ARE IN REASONABLE
AGREEMENT IN BRINGING THIS INTO THE LOCAL AREA. ALTHOUGH RATHER
SIGNIFICANT DIFFERENCES IN THE RESULTING PLACEMENT OF THE QPF AS THE
WAVE INTERACT WITH A TIGHTENING BAROCLINIC ZONE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE NAM/GFS ARE FARTHER NORTH WITH THE QPF
THAN THE GEM/ECMWF...ALTHOUGH THE 00 UTC SUNDAY ECMWF HAS COME A
LITTLE FARTHER NORTH THAN PREVIOUS RUNS. LOOKING AT GFS BUFKIT
SOUNDINGS...THERE DOES APPEAR TO BE A 3 TO 6 HOUR PERIOD WITH STRONG
OMEGA OVER WITHIN THE SNOW GROWTH ZONE IN THE WEST CENTRAL AND
SOUTHWEST...WHICH SHOULD YIELD SOME DECENT SNOW AMOUNTS. THIS AREA
EXTENDS EAST ACROSS CENTRAL NORTH DAKOTA DURING THE DAY MONDAY BUT
STRONG HIGH PRESSURE DROPPING SOUTH FROM CANADA WILL INHIBIT FG
FORCING LATER IN THE DAY. THIS SHOULD REDUCE SNOW AMOUNTS AS THE
WAVE MOVES EASTWARD INTO CENTRAL AND EASTERN NORTH DAKOTA.
A COMBINATION OF HPC SNOW AMOUNTS WITH MODEL QPF YIELDS 3 TO 5
INCHES OF SNOW OVER MUCH OF WEST CENTRAL AND SOUTHWEST NORTH
DAKOTA...WITH 2 TO 3 INCHES EXTENDING EAST INTO GRANT AND MORTON
COUNTIES. SNOW TOTALS TAPER TO AN INCH OR TWO EAST OF THE MISSOURI
RIVER. THE NORTHERN EXTENT OF THE HEAVIER SNOW REMAINS ALONG AND
SOUTH OF LAKE SAKAKAWEA...WEST OF THE MISSOURI...THEN ALONG AND
SOUTH OF THE I94 CORRIDOR EAST OF THE MISSOURI. ALTHOUGH SIGNIFICANT
DIFFERENCES STILL REMAIN...FEEL CONFIDENT ENOUGH THAT A WINTER
WEATHER ADVISORY IS WARRANTED OVER THE SOUTHWEST AND WEST CENTRAL.
CONFIDENCE WANES AS YOU GO EAST...BUT WILL EXTEND THE ADVISORY
EAST TO COVER MOST OF THE AREA WEST OF THE MISSOURI AND SOUTH OF THE
LAKE.
AT THIS TIME IT APPEARS THAT THERE SHOULD BE A QUICK TRANSITION FROM
RAIN TO SNOW AS COLD AIR RUSHES SOUTH LATE SUNDAY NIGHT. HOWEVER...A
PERIOD OF MIXED PRECIPITATION CANNOT BE RULED OUT BEFORE THE COLD
AIR IS FIRMLY ENTRENCHED OVER THE AREA BY MONDAY MORNING. AS THE
CANADIAN HIGH DROPS SOUTH WE SHOULD SEE A NICE ISALLOBARIC COMPONENT
MOVE ACROSS THE WEST AND SOUTH CENTRAL ON MONDAY RESULTING IN
SUSTAINED WINDS OF 15 TO 20 MPH AND GUST OF 25 TO 30 MPH. ALTHOUGH
THERE IS NO LOOSE SNOW...WINDS WILL BE STRONG ENOUGH FOR SOME
BLOWING SNOW AS IT FALLS. THUS WILL MAKE THE ADVISORY FOR SNOW AND
BLOWING SNOW...LASTING FROM LATE SUNDAY NIGHT THROUGH LATE MONDAY
NIGHT.
AS THE MAIN UPPER LOW MOVES ONTO THE PLAINS ON TUESDAY...COLD HIGH
PRESSURE OVER SASKATCHEWAN INTO NORTH DAKOTA SHOULD KEEP THE
NORTHERN EXTEND OF THE SYSTEM RIGHT ALONG THE SOUTH DAKOTA BORDER
WITH ANY SIGNIFICANT PRECIPITATION REMAINING SOUTH OF THE STATE.
THEN AS THE SYSTEM BEGINS TO EJECT NORTHEAST TUESDAY NIGHT THE
PRECIPITATION SHIELD TRIES TO PUSH A BIT FARTHER NORTH AND MAY CLIP
THE FAR SOUTH AND SOUTHEAST COUNTIES WITH LIGHT SNOW. AT THIS TIME
WE ARE KEEPING HIGH CHANCE POPS ALONG THE SOUTH DAKOTA
BORDER...TAPERING TO SLIGHT CHANCE POPS AROUND INTERSTATE 94. THE
NORTHERN HALF OF THE CWA IS EXPECTED TO REMAIN DRY TUESDAY AND
TUESDAY NIGHT. TEMPERATURES DURING THIS PERIOD...MONDAY THROUGH
WEDNESDAY...WILL BE BELOW NORMAL WITH 20S NORTH TO 30S SOUTH. WE DO
SEE SOME SLIGHT WARMING BY AROUND THURSDAY AS THE SYSTEM EXITS TO
OUR EAST...BUT A PROGRESSIVE NORTHWEST FLOW WILL BRING A SERIES OF
UPPER LEVEL WAVES INTO THE AREA LATE IN THE WEEK KEEPING OUR WEATHER
UNSETTLED WITH TEMPERATURES NEAR OR BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 329 AM CDT SUN APR 7 2013
WIDESPREAD STRATUS REMAINS OVER THE REGION THIS MORNING. THE MAIN
HAZARDS TO AVIATION INCLUDE THE MVFR/IFR CONDITIONS ASSOCIATED
WITH THE STRATUS...AND FREEZING RAIN AND MIXED PRECIPITATION
EXPECTED TO MOVE INTO WESTERN NORTH DAKOTA AND THEN SPREAD EAST
THROUGHOUT THE DAY. AS TEMPERATURES WARM AT KDIK...LIGHT FREEZING
RAIN WILL GIVE WAY TO LIGHT RAIN. A BRIEF BREAK IN PRECIPITATION
WILL BE POSSIBLE LATER THIS AFTERNOON...BEFORE THE NEXT ROUND OF
LIGHT RAIN AND MIXED PRECIPITATION ARRIVES SUNDAY EVENING AND
MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ MONDAY TO 1
AM CDT /MIDNIGHT MDT/ TUESDAY FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY FROM 7 AM THIS MORNING TO 1 PM CDT THIS
AFTERNOON FOR NDZ002-010-019>021-034-035-046.
FREEZING RAIN ADVISORY UNTIL 11 AM CDT /10 AM MDT/ THIS MORNING
FOR NDZ001-009-017-018-033-041.
FREEZING RAIN ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS
EVENING FOR NDZ003-011-012-022-023-036-037-047-048-050-051.
&&
$$
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
652 AM EDT SUN APR 7 2013
.SYNOPSIS...
COLD FRONT STALLS ACROSS THE EXTREME NORTHERN SECTIONS OVERNIGHT...THEN
LIFTS BACK NORTH DURING THE DAY ON MONDAY. WEATHER REMAINS UNSETTLE
TUESDAY AND WEDNESDAY. A STRONG COLD FRONT PASSES THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...
CONTINUED TO NUDGE POPS DOWNWARD BETWEEN THE 12Z-18Z TIME FRAME
WITH VERY LIMITED MOISTURE PER LATEST RUC SOUNDINGS AND NEAR-TERM
CONVECTIVE OUTPUT. STILL WILL ALLOW FOR SOME LATE-DAY DEVELOPMENT
ACROSS THE NORTHERN ZONES AROUND THE 21Z SUN-00Z MON TIME FRAME.
ALSO...LATEST NAM12.06 GUIDANCE COMING IN WITH CONTINUED ELEVATED
INSTABILITY ACROSS THE NORTHERN ZONES BETWEEN 00Z-06Z TONIGHT.
EL/S AND CLOUD TOPS LOOK LOW ENOUGH TO LEAVE THUNDER OUT BUT
SOMETHING FOR THE NEXT SHIFT TO EXAMINE.
PREVIOUS FORECAST...
04Z SURFACE OBS DEPICTING SUBTLE WIND SHIFT ACROSS FORECAST AREA
ROUGHLY FROM THE NW OHIO ZONES SE-WARD TOWARDS NICHOLAS/FAYETTE
COUNTIES IN WV. SOUTH OF THIS FEATURE WIND DIRECTION S/SSW WITH
RECOVERING DEWPOINTS GENERALLY IN THE LOWER 30S WHILE NORTH OF
THIS BOUNDARY WIND DIRECTION MORE SSE WITH DEWPOINTS STILL DOWN IN
THE UPPER TEENS TO LOWER 20S. A WEAK LINE OF SHOWERS STRETCHED
FROM FAR NW OHIO INTO CENTRAL INDIANA AND WAS PUSHING ENE-WARD.
APPEARS HOWEVER VERY LITTLE PRECIP WAS ACTUALLY REACHING THE
SURFACE HOWEVER AS NOT FINDING ANY SFC OBS OUT THAT WAY REPORTING
ANY PRECIP WITH VERY HIGH CLOUD BASES STILL AROUND 10KFT. S/W
TROUGH AND SFC LOW PRESSURE TO AFFECT THE AREA TODAY STILL
CURRENTLY OUT OVER THE UPPER MIDWEST...WITH LOW PRESSURE CENTERED
OVER WESTERN WI. PRIMARY FORECAST CONCERN FOR THIS PERIOD REVOLVED
AROUND APPROACHING COLD FRONT AND SUBSEQUENT SHOWERS/THUNDERSTORMS
CHANCES.
OPERATIONAL NWP IN GOOD AGREEMENT WITH REGARD TO GENERAL FEATURES
SUNDAY. AFOREMENTIONED S/W TROUGH AND SFC LOW CONTINUING EASTWARD
TODAY FROM UPPER MICHIGAN AT 12Z TO SW QUEBEC BY 00Z MON. COLD FRONT
ASSOC WITH IT WILL PROGRESS EASTWARD AS WELL BUT WILL STALL OUT WEST
TO EAST NEAR OR JUST NORTH OF THE CWA BORDER BY 00Z MON AS IT
ENCOUNTERS INCREASING W/SW UNIDIRECTIONAL FLOW. INTERESTINGLY
ENOUGH...DESPITE THE PASSAGE OF THE S/W TROUGH TO THE NORTH HEIGHTS
ACTUALLY REMAIN CONSTANT OR EVEN RISE A BIT TODAY. PRECIP CHANCES
SOMEWHAT PROBLEMATIC TODAY WITH A COUPLE OF LIMITING FACTORS TO
CONSIDER. FIRST...AS THE COLD FRONT SLOWS ACROSS CENTRAL OHIO BEST
LLVL MOISTURE CONTINUES ESE-WARD AWAY FROM FRONTAL CONVERGENCE WHICH
MAY HINDER CONTINUED DEVELOPMENT. SECOND...DESPITE THE WARMER DEWPOINTS
TEMPS...A STOUT DRY LAYER STILL EXISTS. LATEST NAM STILL DEPICTING A
20-25F DEGREE DEWPOINTS DEPRESSION EARLY/MID AFTERNOON AT LOCATIONS
SUCH AS PKB...AND SUSPECT THAT THOSE PROGGED DEWPOINTS IN THE UPPER
40S STILL MAY BE ON THE HIGH SIDE. NEAR-TERM CONVECTIVE MODELS ALL
SHOW ANY POTENTIAL LINE OF SHOWERS LIMPING INTO THE AREA AND
DISSIPATING AS IT DOES SO. NOT GOING TO DRASTICALLY CUT POPS WITH
THIS FORECAST PACKAGE BUT WILL REDUCE THEM TO CHANCE CATEGORY AT
BEST. WILL ALSO CONTINUE TO KEEP THE SOUTHERN COALFIELDS AND VA
COUNTIES DRY. REGARDING ANY THUNDER POTENTIAL...AN AXIS OF INSTABILITY
MOVES IN BTWN 18Z SUN AND 00Z MON AHEAD OF FRONT WITH SFC-BASED CAPE
AROUND 300J/KG AND MUCAPE VALUES UP TO AROUND 600J/KG ACROSS THE NW
ZONES. WITH THAT IN MIND WILL CARRY CHANCE THUNDER DURING THIS TIME
ROUGHLY ALONG AND NW OF A LINE FROM CKB TO HTS. ANY CONVECTION WILL
BE HIGH-BASED OF COURSE AND WITH DCAPE VALUES 800-1000J...CAN/T RULE
OUT THE POSSIBILITY OF A BRIEF GUST HERE OR THERE AROUND 20-30KTS
WITH A STORM. OUTSIDE OF PRECIP POTENTIAL...MAX TEMPS ONCE AGAIN
CLIMB INTO THE UPPER 60S/LOWER 70S LOWLANDS WITH PERHAPS MID 60S FAR
NW ZONES WITH ADDITIONAL CLOUD COVER.
BETWEEN 00Z MON-12Z MON THE COLD FRONT REMAINS ESSENTIALLY
STALLED BUT MAY MAKE SOME INROADS JUST INTO THE NORTHERN ZONES
BEFORE RETREATING NORTHWARD TOWARDS DAWN MON. HIGHEST CHANCE POPS
WILL BE ACROSS NE ZONES BUT WILL GENERALLY BEGIN TO WANE DURING
THE OVERNIGHT HOURS...WITH ONLY A SLIGHT CHANCE OF PRECIP FOR
LOWLANDS NORTH OF INTERSTATE 64. A BIT MORE LLVL MOISTURE ARRIVES
ALONG WITH SOME ADDED LIFT FROM AN APPROACHING VORT MAX TO BUMP UP
PRECIP POTENTIAL TOWARDS THE DAWN HOURS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
GFS/ECMWF MODELS IN AGREEMENT WITH H1000 KINK OF THE EAST TO WEST
QUASI STATIONARY FRONTAL BOUNDARY JUST NORTH OF THE AREA...AND THE
NAM FURTHER SOUTH JUST ALONG OUR BORDER BY 12Z MONDAY. EITHER
WAY...PCPN AHEAD OF THE FRONT COULD REACH OUR NORTHERN
SECTORS...SO KEPT HIGH CHANCE POPS THROUGH MONDAY NIGHT INCLUDING
NORTHEAST MOUNTAINS. THIS SCENARIO WILL KEEP MOST OF THE AREA
UNDER THE WARM SECTOR FOR WARMER THAN SEASONAL TEMPERATURES
THROUGH THE PERIOD.
THE CMC/ECMWF BRING A SHORT WAVE AND ASSOCIATED VORTICITY MAX
NORTH OF THE AREA...SUGGESTING MID LEVEL ENERGY COULD INFLUENCE
THE AFOREMENTIONED BOUNDARY TO PRODUCE SHOWERS OR STORMS NORTH OF
OUR CWA. HOWEVER...THE GFS VORT MAX MOVES ACROSS SOUTHEAST OH BY
12Z MONDAY...QUICKLY MOVING NORTHEAST AND A SECOND VORT MAX BY 00Z
TUESDAY. IF THE GFS SOLUTION MATERIALIZE...COULD SEE MORE
CONVECTION DEVELOPING AROUND THE QUASI STATIONARY BOUNDARY LATE
MONDAY...MAINLY ACROSS THE NORTH AND NORTHEAST MOUNTAINS.
ADJUSTED DOWN POPS ACROSS THE EXTREME SOUTHERN CWA AS MAY NOT SEE
MORE THAN AN ISOLATED SHOWER IF ANY MONDAY THROUGH TUESDAY.
KEPT TEMPERATURES AS PREVIOUS FORECAST AS THEY LOOK ON TRACK WITH
A WARMING TREND EXPECTED THROUGH MID WEEK UNDER SOUTHWEST FLOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
FLAT RIDGING EARLY ON GIVES WAY TO TROUGHINESS LATE IN THE WEEK.
STILL A QUESTION OF WHERE AN E-W FRONT BENEATH THE W FLOW ALOFT ENDS
UP. THE ECMWF SHOWS AN EASTERN CANADIAN TROUGH DIGGING INTO THE
NORTHEASTERN STATES...PUSHING A SURFACE FRONT INTO THE CWA TUE
NT-WED AND SO DOES HPC...EVEN AS OTHER MODELS HAVE STRONGER RIDGING
OVER THE AREA BY THAT TIME...PUSHING THE NORTHERN STREAM TROUGH
FARTHER N. AS SUCH...HAVE A SLIGHT CHANCE FOR SHOWERS N TUE NT
FOLLOWED BY A MODEST INCREASE IN POPS FROM THE W WED PER DIURNAL
CONSIDERATIONS IN THE INCREASINGLY WARM AND SOMEWHAT HUMID AIR...AND
A COLD FRONT APPROACHING FROM THE W. TIME OF YEAR AND RECENT TRENDS
DO FAVOR ECMWF/HPC HERE.
ECMWF AND HPC ARE ALSO ONLY SOLNS HOLDING BACK COLD FRONT FROM THE W
UNTIL FRI...GRANTED THE 12Z ECMWF LOOKS ALMOST EXACTLY LIKE HPC
DEPICTION FOR FRI. OPTED WITH A COMPROMISE AND SOMEWHAT SMOOTHED
SOLN WITH THE HIGHEST POPS THU AND THU NT WHEN SHOWERS ARE LIKELY.
POPS...TEMPERATURES AND DEW POINTS GRADUALLY DECREASE FRI AND FRI NT
/NOTWITHSTANDING THE DIURNAL RISE IN TEMPERATURES FRI/ WITH THE
FRONTAL PASSAGE IN AGREEMENT WITH THE HPC WIND FIELDS.
THE INCREASINGLY WARM AND HUMID AIR WILL EVENTUALLY PROVIDE
INSTABILITY ESPECIALLY BUT NOT EXCLUSIVELY WITH THE AFTERNOON
HEATING...AND AVAILABLE FOR STRENGTHENING FLOW AND FORCING TO ACT ON
AS THE FRONT APPROACHES. WHILE MODEL DIFFERENCES WITH THE SYNOPTIC
SCENARIO ARE STILL TO GREAT TO HONE IN ON SPECIFIC PARAMETERS...IT
SEEMS REASONABLE WE MAY BE LOOKING AT AT LEAST MARGINAL FAVORABILITY
FOR SEVERE WED AND / OR THU...AND WELL HONE HWO CONVECTIVE MENTION
INTRODUCED EARLY THIS MORNING IN ON THIS IDEA.
IN THE WAKE OF TH FRONT...THE WEATHER COOLS DOWN AND DRIES OUT FOR
THE START OF NEXT WEEKEND...ALTHOUGH NOT MUCH IF ANY BELOW NORMAL
GIVEN ZONAL FLOW OF PACIFIC ORIGIN.
BLENDED IN MOSGUIDE AND HPC FOR TEMPERATURES IN MOST CASES. THERE
WERE NO MAJOR CHANGES ALTHOUGH NOW HAVE CRW HITTING 80 FOR THE FIRST
TIME THIS YEAR ON WED...WHICH IS IN AGREEMENT WITH THE GFS ENSEMBLE
MEAN AND HPC.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
12Z SUNDAY THROUGH 12Z MONDAY... VFR CONDITIONS ARE EXPECTED TO
PREVAIL THROUGH THE VALID PERIOD. CIGS WILL LOWER AND THICKEN
TODAY ACROSS THE NORTHERN PORTIONS OF THE AREA...BUT ARE EXPECTED
TO REMAIN LOW VFR AROUND 5-7KFT AS A FRONTAL BOUNDARY APPROACHES
THE REGION. A CHANCE OF PRECIP WILL ALSO ACCOMPANY THE FRONT WITH
A CHANCE OF A THUNDERSTORM MAINLY THIS AFTERNOON ACROSS THE NORTH.
BRIEF MVFR VIS IS POSSIBLE WITH A HEAVIER SHOWER AND/OR THUNDERSTORM.
SURFACE WINDS WILL CONTINUE ON THE GUSTY SIDE TODAY OUT OF THE
SOUTHWEST...WITH OCCASIONAL GUSTS AROUND 20KTS LOWLANDS AND 20-25
KT RANGE ACROSS HIGHER TERRAIN COUNTIES. ANOTHER AVIATION CONCERN
AT THE OUTSET THIS MORNING IS A STRONG LOW LEVEL SOUTHWESTERLY JET
CENTERED AROUND 1500FT AGL...WHERE WIND SPEEDS ARE AROUND
35-40KTS. THESE WIND SPEEDS SHOULD BEGIN TO SUBSIDE AROUND 14Z-15Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: WIND GUSTS TODAY MAY BE STRONGER THAN FORECAST.
TIMING OF FRONTAL BOUNDARY AND SHOWERS MAY VARY FROM FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H M H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT AND THURSDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...50
SHORT TERM...ARJ
LONG TERM...TRM
AVIATION...50
AREA FORECAST DISCUSSION
NWS TULSA OK
337 PM CDT SUN APR 7 2013
.DISCUSSION...
CURRENT SURFACE ANALYSIS SHOWS A SUBTLE PRESSURE TROUGH THAT LIES
WEST-EAST ALONG THE KS BORDER. MEANWHILE...MOISTURE CONTINUES TO
SLOWLY INCREASE AND SURGE NORTH. AN ISOLATED SUPERCELL DEVELOPED
ON THE NORTH SIDE OF THIS FEATURE AND CONTINUES EAST ACROSS KS.
THERE IS POTENTIAL LATER THIS AFTERNOON FOR AN ISOLATED STORM TO
DEVELOP OVER FAR NW OK/SW-S CNTRL KS AND TRACK EAST TOWARD NE OK.
THE MOST RECENT AVAILABLE RUN OF THE HRRR HAS BACKED OFF ON THIS
POSSIBILITY BUT IT IS STILL WORTH WATCHING. ANY UPDRAFT THAT CAN
SUSTAIN ITSELF WILL LIKELY ROTATE...GIVEN ~50 KTS OF WESTERLY DEEP
LAYER SHEAR. THE RIGHT MOVING BUNKERS SUPERCELL VECTOR HAS A
MOTION JUST NORTH OF DUE EAST AT 20 KTS. THIS HAS BACKED FROM
EARLIER TODAY...MOST LIKELY DUE TO STRENGTHENING WSW FLOW IN
ADVANCE OF AN IMPULSE OVER NM PER WV IMAGERY. SO THE BEST
POTENTIAL FOR SEVERE STORMS WILL BE NEAR THE KS BORDER AND MAINLY
WEST OF HIGHWAY 75 THROUGH THIS EVENING. VERY LARGE HAIL TO
BASEBALL SIZE IS CERTAINLY POSSIBLE...AND DUE TO STRENGTHENING
0-1KM SHEAR AN ISOLATED TORNADO OR TWO COULD ACCOMPANY A SUPERCELL
IF IT HAPPENED TO PAY US A VISIT THIS EVENING. LOOKS LIKE MORE
WIDESPREAD AND MAINLY ELEVATED STORMS WILL GET ALONG AND NORTH OF
SURFACE TROUGH TOWARD 06Z AS STRENGTHENING LLJ FOCUSES ISENTROPIC
LIFT. THERE IS SOME UNCERTAINTY IN HOW FAR SOUTH TO PUT RAIN
CHANCES...AS OUR LOCAL MODEL DEVELOPS STORMS A BIT FARTHER SOUTH.
FOR NOW WILL HEDGE AND PUT SLIGHT CHCS DOWN TO NEAR I-40.
THE CAP STRENGTHENS ON MONDAY AND THE BOUNDARY TO OUR NORTH
CONSOLIDATES WITH A STRENGTHENING WARM FRONT NEAR THE KS/NEB
BORDER. CHANCES FOR ANY STORMS TOO LOW TO MENTION IN THE FORECAST.
IT IS A HIGHLY CONDITIONAL SETUP (PROBABLY THE BEST OF THE WEEK)...BUT
LOW PROB OF OCCURRENCE.
THE NEXT BIG CHALLENGE WILL BE LATE TUESDAY INTO WEDNESDAY. THE
DATA TODAY HAS NOT REALLY CHANGED MY FORECAST REASONING FROM
YESTERDAY MUCH AT ALL. MODEL SOUNDINGS STILL SHOW A DECENT CAP IN
THE WARM SECTOR TUESDAY...SO IT WILL BE DIFFICULT TO GET STORMS TO GO
WITH THE MAIN UPPER TROUGH STILL WELL WEST AND LACK OF ANY
FOCUSING BOUNDARIES IN OUR AREA. IF A STORM DOES GO IN THE WARM
SECTOR...IT WOULD LIKELY BE BAD...BUT ODDS ARE PRETTY LOW. THE
MOST LIKELY SCENARIO IS FRONTAL FORCING ALONG A SURGING COLD FRONT
WILL PROVIDE THE LIFT NEEDED FOR CONVECTION. HOWEVER...SINCE UPPER
TROUGH IS COMING OUT WITH A POSITIVE TILT...THE UPPER FLOW WILL BE
PARALLEL TO THE FRONT...THUS STORMS THAT DEVELOP WITH THE FRONT
WILL TEND TO BE UNDERCUT QUICKLY. THE ECMWF CONTINUES TO SHOW
ALMOST ALL QPF ON THE COOL SIDE OF THE FRONT...INDICATIVE OF THIS
VERY SCENARIO. I`M NOT SAYING THERE WILL NOT BE SEVERE
WEATHER...BUT THE TENDENCY FOR STORMS TO BE UNDERCUT WILL LIMIT
THE SEVERE POTENTIAL. POST-FRONTAL RAIN AND STORMS ARE FORECAST TO
CONTINUE THRU WEDNESDAY...TAPERING OFF BY THURSDAY MORNING.
TEMPS WILL COOL OFF BEHIND THE FRONT...AND WILL REMAIN THAT WAY
FOR THE LATTER HALF OF THE WEEK AND INTO THE FIRST PART OF THE
WEEKEND. A SUBTLE WAVE WILL PASS THRU THE PLAINS SATURDAY...WITH
THE MAIN EFFECT BEING MORE CLOUD COVER. ONCE THAT PASSES...UPPER
FLOW TRANSITIONS TO SW AND LEE SIDE LOW PRESSURE DEVELOPS OVER SW
KS/SE CO. SOUTHWEST WINDS WILL PREVAIL HERE AND TEMPS WILL REBOUND
QUICKLY BY NEXT SUNDAY.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 61 75 62 75 / 30 10 10 30
FSM 59 74 62 77 / 10 10 10 20
MLC 61 74 63 75 / 10 0 10 20
BVO 60 76 61 74 / 30 10 10 30
FYV 57 71 60 73 / 30 10 10 20
BYV 57 71 59 73 / 30 10 10 20
MKO 59 75 62 74 / 20 10 10 20
MIO 60 74 61 75 / 40 10 10 20
F10 61 74 62 74 / 10 10 10 30
HHW 60 75 63 77 / 0 0 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION...
NWS PORTLAND OR
855 AM PDT SUN APR 7 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM IS NOW PUSHING EAST OF THE CASCADES
THIS MORNING. SNOW IS FALLING IN THE HIGH CASCADES AND WILL INCREASE
TODAY AS FLOW TURNS WESTERLY. SNOW LEVELS WILL BE NEAR OR BELOW THE
CASCADE PASSES. ELSEWHERE RAIN WILL TAPER TO SHOWERS AND SCATTERED
THUNDERSTORMS AS A COLD UPPER LEVEL LOW MOVES ONSHORE THIS AFTERNOON
AND EVENING. THUNDERSTORMS MAY HAVE SMALL HAIL AND GUSTY WINDS
THROUGH THIS EVENING. SHOWERS WILL LINGER INTO MONDAY...THEN TAPER
OFF AS A RIDGE OF HIGH PRESSURE BUILDS FOR A DRIER AND WARMER
WEATHER TUESDAY. ANOTHER SYSTEM IS EXPECTED TO BRING MORE RAIN
WEDNESDAY.
&&
.UPDATE...SURFACE LOW PRESSURE IS NOW FILLING AND MAKING A BEELINE
EAST OF THE CASCADES THIS MORNING. WE DO STILL HAVE A PERIOD OF
PRESSURE RISES BEHIND THE DEPARTING LOW...BUT WIND SUPPORT ALOFT HAS
EASED FROM EARLIER WHERE WE SAW GUSTS TO 60 MPH IN THE COAST RANGE
AND 52 MPH IN THE VALLEY. THIS WILL EASE THE GUST POTENTIAL
SUPPORTING GUSTS OF 30-35 MPH IN THE VALLEY...WITH GUSTS 40-45 MPH
IN THE HIGHER TERRAIN OF THE COAST RANGE. THEREFORE...WILL DROP THE
WIND ADVISORY FOR THE VALLEY AND THE HIGH WIND WARNING FOR THE COAST
RANGE. EXPECT IT TO REMAIN WINDY AT THE EAST END OF THE COLUMBIA
RIVER GORGE AND THE CASCADES TODAY.
COLD ADVECTION WILL CONTINUE TODAY...THUS DO NOT EXPECT MUCH WARMING
FROM CURRENT READINGS. HIGHER ELEVATION SNOTELS IN WASHINGTON HAVE
REPORTED ANYWHERE FROM 3-6 INCHES OF SNOWFALL SO FAR...2" AT THE
SANTIAM PASS SUMMIT WITH 4" OR SO AT THE HIGHER ELEVATION SNOTELS OF
NORTH OREGON...LIGHTER AMOUNTS IN LANE COUNTY WHERE FREEZING LEVELS
ARE STILL A BIT HIGHER. EXPECT ANOTHER 4-6" OF SNOW POSSIBLE IN S
WA...WITH 4-8" IN THE HIGHER ELEVATION CASCADE LOCATIONS TODAY.
WEBCAMS CONFIRM SNOW IS NOW FALLING AT THE PASSES AND EXPECT SNOW
LEVELS TO CONTINUE TO FALL.
WITH REGARDS TO THUNDERSTORMS...WITH CURRENT READINGS IN THE MID TO
UPPER 40S...WE DO NOT EXPECT SFC TEMPS TO RISE MUCH ABOVE 50 TODAY.
DO EXPECT LAPSE RATES TO GET BETTER THIS AFTERNOON AS THE COLD POOL
MOVES IN...AND STILL EXPECT SOME HEAVIER SHOWERS OR THUNDERSTORMS.
KMD
.SHORT TERM...DISCUSSION UNCHANGED....TODAY THROUGH WEDNESDAY...THE
CIRCULATION OF A DEVELOPING LOW PRESSURE SYSTEM IS APPARENT ON
KLGX/KRTX NWS DOPPLER RADARS...PRESENTLY MOVING INTO THE LONG BEACH
PENINSULA OF PACIFIC COUNTY WA. THIS SYSTEM IS A LITTLE FARTHER
NORTH AND A LITTLE STRONGER THAN MOST MODELS SUGGESTED...WITH BUOY
46029 AND HOME WEATHER STATIONS ON THE LONG BEACH PENINSULA
REASONABLY SUGGESTING A CENTRAL PRESSURE OF ABOUT 997 MB.
LATEST RUNS OF THE HRRR 3 KM MODEL DEPICT AN ELONGATED SHAPE TO THE
LOW... EXTENDING FROM THE S WA COAST SOUTHWESTWARD. THIS APPEARS
REASONABLE CONSIDERING THE WIND FIELD APPARENT ALONG THE COAST AND
SHOWN BY BUOYS IN THE COASTAL WATERS. THUS THERE MAY BE A BIT OF A
LULL TO THE WIND ALONG OUR NORTH COAST ZONES INITIALLY AS THE LOW
MOVES ONSHORE. BEHIND THE LOW...HRRR AND NAM HAVE BEEN VERY INSISTENT
ON A STRONG SURGE OF NW-W WIND IN THE BENT BACK OCCLUSION ON THE BACK
SIDE OF THE LOW. THIS WILL CAUSE A SURGE OF WIND FROM THE SW-W AND
EVENTUALLY NW WIND ALONG THE COAST IN THE COMING HOURS...SO IF ONE
SURGE OF WIND EASES IT DOES NOT NECESSARILY MEAN THE EVENT IS OVER.
THE CONSEQUENCES OF THE STRONGER LOW AND MORE NORTHERN TRACK WILL BE
INCREASED CONFIDENCE IN THE WIND ADVISORY FOR THE WILLAMETTE VALLEY
AND A LITTLE CONCERN THE STRONGER WINDS MAY PUSH INTO KELSO/LONGVIEW.
ADDITIONALLY...IT APPEARS A LOW-END HIGH WIND WARNING WILL VERIFY FOR
THE OREGON COAST AND COAST RANGE. WILL LEAVE ALL WIND HIGHLIGHTS AS
IS FOR NOW...THE OVERALL FORECAST LOOKS PRETTY WELL ON TRACK WITH
GUSTS 50-60 MPH WIDESPREAD FOR THE OR COAST AND LOCAL GUSTS TO 70 MPH
FOR THE MOST EXPOSED AREAS. SOUTH WIND GUSTS 25-35 MPH ARE ALREADY
DEVELOPING IN THE TUALATIN AND CENTRAL/SOUTH WILLAMETTE VALLEY. THESE
WILL GET STRONGER WITH 35-45 MPH GUSTS LIKELY TO DEVELOP FOR THE
WILLAMETTE VALLEY AND CLARK COUNTY WITHIN THE NEXT COUPLE HOURS AS
PRESSURE RISES BEGIN IN EARNEST.
ASIDE FROM TRACKING THE LOW AND ASSOCIATED WIND PATTERN THE OTHER
FORECAST CHALLENGES OF THE DAY ARE...1. HOW PROLIFIC THUNDERSTORMS
WILL BE TODAY AND 2. HOW MUCH SNOW WILL FALL IN THE CASCADES.
THUNDERSTORMS...NAM BUFR SOUNDINGS SHOW A VERY STRONG DIRECTIONAL
SHEAR PROFILE WILL QUICKLY BECOME UNIDIRECTIONAL AS THE MORNING
PROGRESSES. HOWEVER A SECONDARY TROUGH IS EXPECTED TO MOVE IN LATER
THIS AFTERNOON AS THE COLD POOL ALOFT DIPS INTO WESTERN WA AND
NORTHWEST OREGON. LAPSE RATES LOOK MARGINAL FOR THUNDERSTORMS...BUT
IMPROVE AS THE AFTERNOON PROGRESSES. WITH SFC TEMPS IN THE LOW 50S WE
SHOULD BE ABLE TO MUSTER ABOUT 400-600 J/KG OF CAPE AND LIFTED
INDICES OF -2 TO -3 DEG C...WHICH WITH LITTLE TO NO CAPPING WOULD BE
PLENTY TO SUGGEST DEEP CONVECTION. SO WE INCREASED THUNDERSTORM
COVERAGE TO SCATTERED AS THIS SETUP IS ABOUT AS GOOD AS IT GETS IN A
POST-FRONTAL ENVIRONMENT. WITH 25-35 KT WESTERLY FLOW AT 850 MB ANY
ORGANIZED THUNDERSTORMS MAY MIX DOWN GUSTY WINDS. TERRAIN DRIVEN FLOW
MAY PRODUCE A LITTLE DIRECTIONAL SHEAR AS WELL...WHICH COULD LEAD TO
SOME WEAK ROTATION WITH THE STRONGER CELLS. ANY THUNDERSTORMS SHOULD
DIE DOWN QUICKLY AFTER SUNSET AS SFC TEMPS COOL AND THE AIR MASS
STABILIZES.
SNOW...SNOW AMOUNTS IN THE CASCADES HAVE THUS FAR BEEN UNIMPRESSIVE
WITH ABOUT 2-4 INCHES MOST LOCATIONS ABOVE 4000 FT. HOWEVER AS LOW
PRESSURE CROSSES THE CASCADES FLOW WILL BECOME MORE OROGRAPHIC. WEST
WINDS 25-35 KT AT 850 MB WILL ENHANCE SNOWFALL IN THE CASCADES...SO A
GOOD 6-12 INCHES LOOK LIKELY ABOVE 4500-5000 FT BY LATER TONIGHT.
SNOW LEVELS WILL BE LOWERING...SO THE PASSES COULD GET A FEW SLUSHY
INCHES OF SNOW THIS AFTERNOON AND TONIGHT. SNOW WILL GRADUALLY TAPER
OFF MONDAY.
A WEAK SHORTWAVE MAY KEEP A FEW SHOWERS IN THE REGION THROUGH MONDAY.
HOWEVER IT APPEARS WE WILL DRY OUT BY TUESDAY AS RIDGING BUILDS INTO
OREGON AND WASHINGTON. 850 MB TEMPS REBOUND TO ABOUT +5 DEG C TUE
AFTERNOON...PROBABLY ENOUGH FOR LOWER 60S IN THE VALLEYS. THIS RIDGE
PROBABLY WILL NOT BE STRONG TO KEEP CLOUD COVER TO OUR NORTH...AND
THE NORTH COAST MAY GET BRUSHED WITH SOME RAIN OR DRIZZLE TUE/TUE
NIGHT. THE RIDGE COLLAPSES WEDNESDAY...ALLOWING ANOTHER FRONT TO SAG
SOUTH AND SPREAD RAIN INTO OUR FORECAST AREA. WEAGLE
.LONG TERM...MAIN CHANGES TO THE EXTENDED FORECAST WERE TO INCREASE
POPS SLIGHTLY AS IT APPEARS WE REMAIN IN A ZONAL AND PROGRESSIVE
PATTERN AFTER WEDNESDAYS FRONTAL SYSTEM. THIS MEANS NEAR OR SLIGHTLY
BELOW NORMAL TEMPERATURES WITH RAIN AT TIMES FOR THE LATE WEEK
PERIOD. WEAGLE
&&
.AVIATION...A MIX OF MVFR/VFR AND BREEZY CONDITIONS WILL CONTINUE
ACROSS MUCH OF THE FORECAST AREA THROUGH TODAY. CONDITIONS WILL
GRADUALLY RELAX BY THIS AFTERNOON AS THE AIR MASS DESTABILIZES...
WITH OCCASIONAL SHOWERS BRINGING A THREAT FOR BRIEF HEAVY
RAIN...SMALL HAIL AND LIGHTNING. THIS ACTIVITY SHOULD BEGIN TO
WANE BY THIS EVENING. A RELATIVELY UNSTABLE AIR MASS WILL PERSIST
INTO TONIGHT KEEPING MANY LOCATIONS VFR...WITH SOME PATCHY MVFR
CIGS.
KPDX AND APPROACHES...EXPECT PREDOMINANTLY VFR CONDITIONS THE NEXT
24 HRS. GUSTY WINDS CONTINUE THROUGH EARLY THIS AFTERNOON. THERE
IS A CHANCE FOR A THUNDERSTORM TO IMPACT THE TERMINAL THIS
AFTERNOON AND EARLY EVENING...BRINGING OCCASIONAL MVFR CIGS WITH
IT. /27
&&
.MARINE...THE SYSTEM THAT BROUGHT STRONG WINDS TO THE COASTAL
WATERS HAS NOW PUSHED FURTHER INLAND THIS MORNING. WESTERLY WINDS
WILL CONTINUE IN THE 20 TO 25 KT RANGE BEHIND THE FRONT THROUGH
LATE TONIGHT...BUT MAY SEE BRIEF PERIODS THIS MORNING WHERE WINDS
DROP BELOW CRITERIA. SEAS WILL ALSO REMAIN AROUND 10 TO 12 FT
TODAY AND TONIGHT.
HIGH PRESSURE WILL THEN BEGIN TO BUILD INTO THE REGION MONDAY...
CAUSING WINDS TO SUBSIDE AND SEAS TO RELAX. THIS SHOULD CONTINUE
UNTIL MIDDAY TUESDAY WHEN A WEAKENING FRONT BRINGS A BURST OF 20
TO 25 KT WINDS TO PRIMARILY THE NORTHERN WATERS. ANOTHER STORM
SYSTEM WILL SLIDE BY TO OUR NORTH WEDNESDAY...CAUSING SOUTH WINDS
TO INCREASE ONCE AGAIN AND SEAS TO BRIEFLY POP UP NEAR 10 FT.
HIGH PRESSURE SHOULD THEN CAUSE WINDS AND SEAS TO RELAX LATE IN
THE WORK WEEK. /NEUMAN /27
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES.
WA...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT MONDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT MONDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 5 AM
PDT MONDAY.
&&
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...CORRECTION
NWS PORTLAND OR
305 AM PDT SUN APR 7 2013
.SYNOPSIS...A DEEPENING LOW PRESSURE SYSTEM IS MOVING ONSHORE NEAR
THE LONG BEACH PENINSULA OF SOUTHERN WA...BRINGING INCREASINGLY
STRONG WINDS TO THE OREGON COAST. GUSTY WINDS ARE BEGINNING TO SPREAD
ACROSS THE COAST RANGE AND INTO THE WILLAMETTE VALLEY...THIS WILL BE
THE TREND FOR THIS MORNING. SNOW IS FALLING IN THE HIGH CASCADES AND
WILL INCREASE TODAY AS FLOW TURNS WESTERLY. SNOW LEVELS WILL BE NEAR
OR BELOW THE CASCADE PASSES. ELSEWHERE RAIN WILL TAPER TO SHOWERS AND
SCATTERED THUNDERSTORMS AS A COLD UPPER LEVEL LOW MOVES ONSHORE THIS
AFTERNOON AND EVENING. THUNDERSTORMS MAY HAVE SMALL HAIL AND GUSTY
WINDS THROUGH THIS EVENING. SHOWERS WILL LINGER INTO MONDAY...THEN
TAPER OFF AS A RIDGE OF HIGH PRESSURE BUILDS FOR A DRIER AND WARMER
WEATHER TUESDAY. ANOTHER SYSTEM IS EXPECTED TO BRING MORE RAIN
WEDNESDAY.
&&
.SHORT TERM...TODAY THROUGH WEDNESDAY...THE CIRCULATION OF A
DEVELOPING LOW PRESSURE SYSTEM IS APPARENT ON KLGX/KRTX NWS DOPPLER
RADARS...PRESENTLY MOVING INTO THE LONG BEACH PENINSULA OF PACIFIC
COUNTY WA. THIS SYSTEM IS A LITTLE FARTHER NORTH AND A LITTLE
STRONGER THAN MOST MODELS SUGGESTED...WITH BUOY 46029 AND HOME
WEATHER STATIONS ON THE LONG BEACH PENINSULA REASONABLY SUGGESTING A
CENTRAL PRESSURE OF ABOUT 997 MB.
LATEST RUNS OF THE HRRR 3 KM MODEL DEPICT AN ELONGATED SHAPE TO THE
LOW... EXTENDING FROM THE S WA COAST SOUTHWESTWARD. THIS APPEARS
REASONABLE CONSIDERING THE WIND FIELD APPARENT ALONG THE COAST AND
SHOWN BY BUOYS IN THE COASTAL WATERS. THUS THERE MAY BE A BIT OF A
LULL TO THE WIND ALONG OUR NORTH COAST ZONES INITIALLY AS THE LOW
MOVES ONSHORE. BEHIND THE LOW...HRRR AND NAM HAVE BEEN VERY INSISTENT
ON A STRONG SURGE OF NW-W WIND IN THE BENT BACK OCCLUSION ON THE BACK
SIDE OF THE LOW. THIS WILL CAUSE A SURGE OF WIND FROM THE SW-W AND
EVENTUALLY NW WIND ALONG THE COAST IN THE COMING HOURS...SO IF ONE
SURGE OF WIND EASES IT DOES NOT NECESSARILY MEAN THE EVENT IS OVER.
THE CONSEQUENCES OF THE STRONGER LOW AND MORE NORTHERN TRACK WILL BE
INCREASED CONFIDENCE IN THE WIND ADVISORY FOR THE WILLAMETTE VALLEY
AND A LITTLE CONCERN THE STRONGER WINDS MAY PUSH INTO KELSO/LONGVIEW.
ADDITIONALLY...IT APPEARS A LOW-END HIGH WIND WARNING WILL VERIFY FOR
THE OREGON COAST AND COAST RANGE. WILL LEAVE ALL WIND HIGHLIGHTS AS
IS FOR NOW...THE OVERALL FORECAST LOOKS PRETTY WELL ON TRACK WITH
GUSTS 50-60 MPH WIDESPREAD FOR THE OR COAST AND LOCAL GUSTS TO 70 MPH
FOR THE MOST EXPOSED AREAS. SOUTH WIND GUSTS 25-35 MPH ARE ALREADY
DEVELOPING IN THE TUALATIN AND CENTRAL/SOUTH WILLAMETTE VALLEY. THESE
WILL GET STRONGER WITH 35-45 MPH GUSTS LIKELY TO DEVELOP FOR THE
WILLAMETTE VALLEY AND CLARK COUNTY WITHIN THE NEXT COUPLE HOURS AS
PRESSURE RISES BEGIN IN EARNEST.
ASIDE FROM TRACKING THE LOW AND ASSOCIATED WIND PATTERN THE OTHER
FORECAST CHALLENGES OF THE DAY ARE...1. HOW PROLIFIC THUNDERSTORMS
WILL BE TODAY AND 2. HOW MUCH SNOW WILL FALL IN THE CASCADES.
THUNDERSTORMS...NAM BUFR SOUNDINGS SHOW A VERY STRONG DIRECTIONAL
SHEAR PROFILE WILL QUICKLY BECOME UNIDIRECTIONAL AS THE MORNING
PROGRESSES. HOWEVER A SECONDARY TROUGH IS EXPECTED TO MOVE IN LATER
THIS AFTERNOON AS THE COLD POOL ALOFT DIPS INTO WESTERN WA AND
NORTHWEST OREGON. LAPSE RATES LOOK MARGINAL FOR THUNDERSTORMS...BUT
IMPROVE AS THE AFTERNOON PROGRESSES. WITH SFC TEMPS IN THE LOW 50S WE
SHOULD BE ABLE TO MUSTER ABOUT 400-600 J/KG OF CAPE AND LIFTED
INDICES OF -2 TO -3 DEG C...WHICH WITH LITTLE TO NO CAPPING WOULD BE
PLENTY TO SUGGEST DEEP CONVECTION. SO WE INCREASED THUNDERSTORM
COVERAGE TO SCATTERED AS THIS SETUP IS ABOUT AS GOOD AS IT GETS IN A
POST-FRONTAL ENVIRONMENT. WITH 25-35 KT WESTERLY FLOW AT 850 MB ANY
ORGANIZED THUNDERSTORMS MAY MIX DOWN GUSTY WINDS. TERRAIN DRIVEN FLOW
MAY PRODUCE A LITTLE DIRECTIONAL SHEAR AS WELL...WHICH COULD LEAD TO
SOME WEAK ROTATION WITH THE STRONGER CELLS. ANY THUNDERSTORMS SHOULD
DIE DOWN QUICKLY AFTER SUNSET AS SFC TEMPS COOL AND THE AIR MASS
STABILIZES.
SNOW...SNOW AMOUNTS IN THE CASCADES HAVE THUS FAR BEEN UNIMPRESSIVE
WITH ABOUT 2-4 INCHES MOST LOCATIONS ABOVE 4000 FT. HOWEVER AS LOW
PRESSURE CROSSES THE CASCADES FLOW WILL BECOME MORE OROGRAPHIC. WEST
WINDS 25-35 KT AT 850 MB WILL ENHANCE SNOWFALL IN THE CASCADES...SO A
GOOD 6-12 INCHES LOOK LIKELY ABOVE 4500-5000 FT BY LATER TONIGHT.
SNOW LEVELS WILL BE LOWERING...SO THE PASSES COULD GET A FEW SLUSHY
INCHES OF SNOW THIS AFTERNOON AND TONIGHT. SNOW WILL GRADUALLY TAPER
OFF MONDAY.
A WEAK SHORTWAVE MAY KEEP A FEW SHOWERS IN THE REGION THROUGH MONDAY.
HOWEVER IT APPEARS WE WILL DRY OUT BY TUESDAY AS RIDGING BUILDS INTO
OREGON AND WASHINGTON. 850 MB TEMPS REBOUND TO ABOUT +5 DEG C TUE
AFTERNOON...PROBABLY ENOUGH FOR LOWER 60S IN THE VALLEYS. THIS RIDGE
PROBABLY WILL NOT BE STRONG TO KEEP CLOUD COVER TO OUR NORTH...AND
THE NORTH COAST MAY GET BRUSHED WITH SOME RAIN OR DRIZZLE TUE/TUE
NIGHT. THE RIDGE COLLAPSES WEDNESDAY...ALLOWING ANOTHER FRONT TO SAG
SOUTH AND SPREAD RAIN INTO OUR FORECAST AREA. WEAGLE
.LONG TERM...MAIN CHANGES TO THE EXTENDED FORECAST WERE TO INCREASE
POPS SLIGHTLY AS IT APPEARS WE REMAIN IN A ZONAL AND PROGRESSIVE
PATTERN AFTER WEDNESDAYS FRONTAL SYSTEM. THIS MEANS NEAR OR SLIGHTLY
BELOW NORMAL TEMPERATURES WITH RAIN AT TIMES FOR THE LATE WEEK
PERIOD. WEAGLE
&&
.AVIATION...EXPECT A MIX OF IFR AND MVFR CONDITIONS ALONG THE COAST
THIS MORNING WITH A MIX OF MVFR AND VFR CONDITIONS FOR THE INTERIOR
TAF SITES. A BURST OF HIGHER SOUTH WINDS SHOULD OCCUR FOR MOST TAF
SITES IN THE NEXT 1 TO 4 HOURS...BEFORE SLOWLY RELAXING THROUGH THE
DAY. CONDITIONS SHOULD BEGIN TO IMPROVE ON THE WHOLE AREA WIDE THIS
AFTERNOON AS THE AIRMASS DESTABILIZES. HOWEVER...WITH THE AIRMASS
DESTABILIZING...EXPECT SHOWERS TO PULSE UP AND DOWN...SOME OF WHICH
WILL PRODUCE BRIEF HEAVY RAIN...SMALL HAIL AND LIGHTNING. THIS
ACTIVITY SHOULD BEGIN TO WANE DURING THE EVENING HOURS. A RELATIVELY
UNSTABLE AIRMASS WILL PERSIST INTO TONIGHT KEEPING MANY LOCATIONS
VFR...WITH SOME PATCHY MVFR CIGS.
KPDX AND APPROACHES...EXPECT A MIX OF MVFR AND VFR CONDITIONS THIS
MORNING TO TRANSITION PRIMARILY TO VFR AROUND MIDDAY. EAST WINDS
SHOULD SHIFT TO EAST...AND GUST PRETTY STRONGLY OUT OF THE SOUTH
STARTING AROUND 5 AM. THERE IS A CHANCE FOR A THUNDERSTORM TO
IMPACT THE TERMINAL THIS AFTERNOON AND EARLY EVENING. OTHERWISE...A
RELATIVELY UNSTABLE AIRMASS TONIGHT SHOULD KEEP CIGS HIGH END MVFR
OR VFR OVERNIGHT. /NEUMAN
&&
.MARINE...AN ELONGATED BOOMERANG LOOKING LOW PRESSURE IS CURRENTLY
PUSHING ASHORE NEAR THE COLUMBIA RIVER MOUTH. GALE FORCE WINDS
HAVE PRIMARILY REMAINED SOUTH OF THE LOW PRESSURE...ALTHOUGH
EASTERLY WINDS REACHED INTO GALE FORCE BRIEFLY AT BUOY 29 EARLIER
THIS MORNING.
A HIGH RESOLUTION MODEL CONTINUES TO INSIST A BURST OF HIGHER
WINDS ON THE BACKSIDE OF THE LOW PRESSURE WILL SWING INTO THE
CENTRAL OREGON COAST AROUND 4 AM. AS A RESULT...WINDS MAY
TEMPORARILY SPIKE IN THE NEXT HOUR OR TWO ACROSS THE NORTH CENTRAL
OREGON WATERS BEFORE BEGINNING TO SUBSIDE BETWEEN 5 AM AND 8 AM.
EXPECT WIND GUSTS OF 20 TO 30 KT TO CONTINUE AREA WIDE TODAY WITH
SEAS REMAINING ABOVE 10 FT.
HIGH PRESSURE WILL THEN BEGIN TO BUILD INTO THE REGION
MONDAY...CAUSING WINDS TO SUBSIDE AND SEAS TO RELAX. THIS SHOULD
CONTINUE UNTIL MIDDAY TUESDAY WHEN A WEAKENING FRONT BRINGS A
BURST OF 20 TO 25 KT WINDS TO PRIMARILY THE NORTHERN WATERS.
ANOTHER STORM SYSTEM WILL SLIDE BY TO OUR NORTH WEDNESDAY...CAUSING
SOUTH WINDS TO INCREASE ONCE AGAIN AND SEAS TO BRIEFLY POP UP NEAR
10 FT.
HIGH PRESSURE SHOULD THEN CAUSE WINDS AND SEAS TO RELAX LATE IN
THE WORK WEEK. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES.
WIND ADVISORY UNTIL 11 AM PDT THIS MORNING FOR CENTRAL
WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-SOUTH
WILLAMETTE VALLEY.
HIGH WIND WARNING UNTIL 11 AM PDT THIS MORNING FOR CENTRAL COAST
RANGE OF WESTERN OREGON-COAST RANGE OF NORTHWEST OREGON.
HIGH WIND WARNING UNTIL 8 AM PDT THIS MORNING FOR CENTRAL OREGON
COAST-NORTH OREGON COAST.
WA...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
WIND ADVISORY UNTIL 11 AM PDT THIS MORNING FOR GREATER VANCOUVER
AREA.
PZ...GALE WARNING UNTIL 8 AM PDT THIS MORNING FOR COASTAL WATERS FROM
CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PDT THIS EVENING.
&&
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1032 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 825 PM CDT MON APR 8 2013
COMPLEX WEATHER SYSTEM EXPECTED TO BEGIN TO AFFECT THE AREA FOR
THE NEXT 2 TO 3 DAYS. RADAR SHOWS PRECIPITATION ALREADY
APPROACHING GREGORY COUNTY. THE COLD AIR HAS MOVED INTO AREAS WEST
OF THE JAMES FASTER THAN EXPECTED WITH MOST AREAS WEST OF A HURON
TO GREGORY SD LINE ALREADY AT OR BELOW FREEZING AS IS BROOKINGS.
IN ADDITION...KABR 00Z SOUNDING SHOWS A COLD LAYER DOWN TO -6C AT
925 MB. FOR AREAS THAT ARE ABOVE FREEZING HIGHER IN THE
ATMOSPHERE...THIS TYPE OF SOUNDING IS VERY SUPPORTIVE OF SLEET
RATHER THAN FREEZING RAIN. NAM AND RAP BUFR SOUNDINGS ALSO DEPICT
THIS COLD LAYER BELOW THE WARM LAYER OF AIR OVER MOST OF SOUTHEAST
SD INCLUDING SIOUX FALLS AND YANKTON. BUT NOT QUITE AS COLD TOWARD
MARSHALL AND SLAYTON. THIS SUGGESTS THAT THE PERIOD OF FREEZING
RAIN MAY NOT LAST AS LONG AS PREVIOUSLY EXPECTED IN SE SD BUT
THERE COULD BE A QUITE A PERIOD OF SLEET BETWEEN THE HEAVY
SNOWFALL TOWARD HON AND 9V9 AND THE RAIN THAT WILL BE FALLING OVER
MOST OF NW IA. IF THIS SCENARIO PANS OUT...WOULD EXPECT THAT MOST
AREAS IN SE SD WILL SEE AT MOST 0.15 IN. OF ICE ACCUM WITH MOST
AREAS RECEIVING LESS THAN A TENTH OF AN INCH. HOWEVER...LOCATIONS
NEAR SIOUX FALLS AND YANKTON COULD SEE UP TO AN INCH OF SLEET
LATER TONIGHT AND TUESDAY MORNING. OVER SW MN...WHERE TEMPERATURE WILL BE
MARGINAL FOR SLEET...THERE IS STILL THE POTENTIAL FOR UP TO A
QUARTER INCH OF ICE BEFORE IT CHANGES TO A MIX OF SLEET AND SNOW
LATER IN THE MORNING. LATER IN THE DAY ON TUESDAY...PRECIPITATOIN
RATES ARE EXPECTED TO DECREASED SOUTH OF A MARSHALL TO LAKE ANDES
LINE. WOULD NOT BE SURPRISED IS PORTIONS OF THIS AREA GO BACK TO
FREEZING DRIZZLE WHERE TEMPERATURES ARE EXPECTED TO BE BELOW
FREEZING...AND DRIZZLE IN NW IA WHERE IT WILL BE ABOVE FREEZING.
FOR SIMPLICITY WILL JUST KEEP IT AS MENTION OF FREEZING RAIN OR
RAIN IN FORECAST.
BASED ON THIS SCENARIO...HAVE DECIDED TO GO WITH A WINTER STORM
WARNING BEGINNING AT 06Z...1 AM CDT TUE...FOR
LYON...LINCOLN...PIPESTON...AND MURRAY COUNTIES IN SW MN. FOR THE
REMAINDER OF THE CURRENT WINTER STORM WATCH...INCLUDING SIOUX
FALLS AND CANTON...WILL GO WITH A WINTER WEATHER ADVISORY FROM
09Z...4 AM CDT TUE...THROUGH 00Z WED...AND THEN CONTINUE THE
WATCH FROM 00Z WED THROUGH 00Z THU.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 351 PM CDT MON APR 8 2013
AS HAS BEEN THE CASE THE LAST FEW DAYS...THIS SYSTEM CONTINUES TO BE
PROBLEMATIC WITH PRECIPITATION TYPE ISSUES. TONIGHT IT APPEARS AS THOUGH A
BAND OF PRECIPITATION WILL DEVELOP ACROSS EAST CENTRAL NEBRASKA AND
LIFT NORTH THROUGH THE OVERNIGHT. AS IT MOVES INTO THE COOLER
AIR...PRECIPITATION ALONG AND WEST OF A LINE FROM YANKTON TO SIOUX
FALLS TO MARSHALL IS EXPECTED TO ENCOUNTER WARM NOSE ALOFT FROM
800-700 MB...BUT WITH SUB FREEZING TEMPERATURES AT THE SURFACE FALL
AS FREEZING RAIN. AS THE WARM LAYER GRADUALLY COOLS FROM
WEST...PRECIPITATION ALONG AND WEST OF THE JAMES RIVER VALLEY MAY
CHANGE OVER TO SNOW. SNOW SHOULD BE FAIRLY WET AND HEAVY...SO
DESPITE STRONG WINDS THINK THE MAIN THREAT WILL BE ICING AND SNOW AS
OPPOSED TO BLOWING SNOW. THEREFORE...AM GOING WINTER STORM WARNING
FOR COMBINATION OF SNOW AND ICING ISSUES THROUGH THE FORECAST
PERIOD.
ONCE THE PRECIPITATION BAND LIFTS TO THE NORTH...QUESTIONS START TO
ENTER INTO THE FORECAST. WITH LACK OF LARGE SCALE FORCING ACROSS
THE AREA...AM CONCERNED THAT PRECIPITATION MAY SHUT DOWN FOR A BULK
OF THE DAY ON TUESDAY. LARGE SCALE SUBSIDENCE ALOFT LEADS MID LEVEL
DRYING TO THE POINT WHERE THE DENDRITIC LAYER REMAINS UNSATURATED.
WHAT IS VERY INTERESTING ARE MODEL SOUNDINGS ARE NEARLY CONVECTIVE
WITH STEEP LAPSE RATES ALOFT FROM NEAR 800 MB WITH LITTLE CAPPING.
IF CONVECTIVE POTENTIAL REMAINS UNREALIZED...SHOULD BE LEFT WITH
AREAS OF DRIZZLE/FREEZING DRIZZLE UNTIL THE THE MAIN WAVE APPROACHES
TUESDAY EVENING. MODEL DIFFERENCES CONTINUE WITH TEMPERATURE
PROFILES. GFS CONTINUES TO BE MORE AGGRESSIVE WITH COLD AIR THAN
NAM...RESULTING IN SNOW FORECAST 50-70 MILES FURTHER TO THE EAST
THAN THE NAM. NAM LEADS TO A FAIRLY BROAD AREA WITHIN 30-40 MILES
EAST/WEST OF ICE FROM LAKE ANDES THROUGH BROOKINGS. STILL HAVE AXIS
WITHIN THE SAME REGION FOR HEAVIEST ICING POTENTIAL...WITH ICE
AMOUNTS UP TO A THIRD OF AN INCH OF ICE. IF THIS ICE WERE TO BECOME
A REALITY...THERE IS A SIGNIFICANT CONCERN WITH THE STRONG WIND OF
THE IMPACT IT WOULD HAVE WITH POWER LINES AND TREES ACROSS THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 351 PM CDT MON APR 8 2013
AS COLDER AIR WORKS IN ALOFT...EXPECT PRECIPITATION TO CHANGE OVER
TO SNOW TUESDAY NIGHT INTO WEDNESDAY ACROSS THE AREA. HEAVIEST
PRECIPITATION SHOULD BE EXPECTED ACROSS THE AREA TUESDAY NIGHT WITH
UPPER WAVE MOVING THROUGH...AND THEN THE TROWAL SETTING UP ON
WEDNESDAY INTO THURSDAY.
SYSTEM PULLING OUT A LITTLE SLOWER...SO WILL LINGER A CHANCE OF
LIGHT SNOW INTO THURSDAY...ESPECIALLY ACROSS OUR EAST. POTENTIALLY
COULD SEE ANOTHER INCH OR TWO IN NORTHEAST PARTS OF THE CWA INTO
THIS PERIOD. BRIEF BREAK IN PRECIP STILL LOOKS OK BETWEEN WAVES
FRIDAY/FRIDAY NIGHT...AND IF ECMWF IS CORRECT THIS BREAK COULD
EXTEND INTO THE WEEKEND AS WELL...AS THIS MODEL IS SLOWER THAN
GFS/GEM WITH NEXT NORTHERN STREAM WAVE TO AFFECT THE AREA. HOWEVER
GIVEN UNCERTAINTY WITH TIMING WILL KEEP LOW POPS STARTING WITH A
SLIGHT CHANCE SATURDAY...THEN GENERALLY LOW TO MID CHANCE RANGE
SATURDAY NIGHT THROUGH MONDAY.
TEMPERATURES ARE ANOTHER ISSUE THROUGH THE EXTENDED. TEMPERATURE
CONSENSUS FORECAST SEEMS TO BE WEIGHTED TOWARD NUMERICAL GUIDANCE
WHICH TRENDS TOWARD MUCH WARMER CLIMATOLOGY. HOWEVER...RAW MODEL
GUIDANCE REMAINS ON THE COOL SIDE OF NORMAL THROUGHOUT THE PERIOD
AND HAVE HEDGED TEMPERATURES DOWN A FEW DEGREES TO ACCOUNT FOR THIS.
UNFORTUNATELY...THIS INTRODUCES POTENTIAL FOR RAIN/SNOW MIX AT TIMES
ACROSS OUR NORTHERN CWA WITH ANY PRECIPITATION THROUGH WEEKEND INTO
MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1032 PM CDT MON APR 8 2013
WIDESPREAD IFR CEILINGS CAN BE EXPECTED THROUGH 06Z WEDNESDAY.
FREEZING RAIN AND SLEET WILL DEVELOP DURING THE NIGHT WEST OF YKN-
FSD-MML WITH RAIN AND ISOLATED THUNDERSTORMS TO THE EAST. THE
RAIN WILL CHANGE OVER TO SNOW WEST OF A BKX-PKS LINE AFTER 12Z
TUESDAY...WITH RAIN...FREEZING RAIN OR SLEET TO THE EAST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM CDT TUESDAY FOR SDZ062-
066-067-069-070.
WINTER STORM WARNING UNTIL 7 PM CDT WEDNESDAY FOR SDZ038>040-
053>056-059>061-065-068.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR SDZ062-066-067-069-070.
WINTER STORM WARNING UNTIL 1 PM CDT WEDNESDAY FOR SDZ050-052-057-
058-063-064.
MN...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM CDT TUESDAY FOR MNZ098.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR MNZ098.
WINTER STORM WARNING UNTIL 7 PM CDT WEDNESDAY FOR MNZ071-072-080-
097.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
826 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 825 PM CDT MON APR 8 2013
COMPLEX WEATHER SYSTEM EXPECTED TO BEGIN TO AFFECT THE AREA FOR
THE NEXT 2 TO 3 DAYS. RADAR SHOWS PRECIPITATION ALREADY
APPROACHING GREGORY COUNTY. THE COLD AIR HAS MOVED INTO AREAS WEST
OF THE JAMES FASTER THAN EXPECTED WITH MOST AREAS WEST OF A HURON
TO GREGORY SD LINE ALREADY AT OR BELOW FREEZING AS IS BROOKINGS.
IN ADDITION...KABR 00Z SOUNDING SHOWS A COLD LAYER DOWN TO -6C AT
925 MB. FOR AREAS THAT ARE ABOVE FREEZING HIGHER IN THE
ATMOSPHERE...THIS TYPE OF SOUNDING IS VERY SUPPORTIVE OF SLEET
RATHER THAN FREEZING RAIN. NAM AND RAP BUFR SOUNDINGS ALSO DEPICT
THIS COLD LAYER BELOW THE WARM LAYER OF AIR OVER MOST OF SOUTHEAST
SD INCLUDING SIOUX FALLS AND YANKTON. BUT NOT QUITE AS COLD TOWARD
MARSHALL AND SLAYTON. THIS SUGGESTS THAT THE PERIOD OF FREEZING
RAIN MAY NOT LAST AS LONG AS PREVIOUSLY EXPECTED IN SE SD BUT
THERE COULD BE A QUITE A PERIOD OF SLEET BETWEEN THE HEAVY
SNOWFALL TOWARD HON AND 9V9 AND THE RAIN THAT WILL BE FALLING OVER
MOST OF NW IA. IF THIS SCENARIO PANS OUT...WOULD EXPECT THAT MOST
AREAS IN SE SD WILL SEE AT MOST 0.15 IN. OF ICE ACCUM WITH MOST
AREAS RECEIVING LESS THAN A TENTH OF AN INCH. HOWEVER...LOCATIONS
NEAR SIOUX FALLS AND YANKTON COULD SEE UP TO AN INCH OF SLEET
LATER TONIGHT AND TUESDAY MORNING. OVER SW MN...WHERE TEMPERATURE WILL BE
MARGINAL FOR SLEET...THERE IS STILL THE POTENTIAL FOR UP TO A
QUARTER INCH OF ICE BEFORE IT CHANGES TO A MIX OF SLEET AND SNOW
LATER IN THE MORNING. LATER IN THE DAY ON TUESDAY...PRECIPITATOIN
RATES ARE EXPECTED TO DECREASED SOUTH OF A MARSHALL TO LAKE ANDES
LINE. WOULD NOT BE SURPRISED IS PORTIONS OF THIS AREA GO BACK TO
FREEZING DRIZZLE WHERE TEMPERATURES ARE EXPECTED TO BE BELOW
FREEZING...AND DRIZZLE IN NW IA WHERE IT WILL BE ABOVE FREEZING.
FOR SIMPLICITY WILL JUST KEEP IT AS MENTION OF FREEZING RAIN OR
RAIN IN FORECAST.
BASED ON THIS SCENARIO...HAVE DECIDED TO GO WITH A WINTER STORM
WARNING BEGINNING AT 06Z...1 AM CDT TUE...FOR
LYON...LINCOLN...PIPESTON...AND MURRAY COUNTIES IN SW MN. FOR THE
REMAINDER OF THE CURRENT WINTER STORM WATCH...INCLUDING SIOUX
FALLS AND CANTON...WILL GO WITH A WINTER WEATHER ADVISORY FROM
09Z...4 AM CDT TUE...THROUGH 00Z WED...AND THEN CONTINUE THE
WATCH FROM 00Z WED THROUGH 00Z THU.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 351 PM CDT MON APR 8 2013
AS HAS BEEN THE CASE THE LAST FEW DAYS...THIS SYSTEM CONTINUES TO BE
PROBLEMATIC WITH PRECIPITATION TYPE ISSUES. TONIGHT IT APPEARS AS THOUGH A
BAND OF PRECIPITATION WILL DEVELOP ACROSS EAST CENTRAL NEBRASKA AND
LIFT NORTH THROUGH THE OVERNIGHT. AS IT MOVES INTO THE COOLER
AIR...PRECIPITATION ALONG AND WEST OF A LINE FROM YANKTON TO SIOUX
FALLS TO MARSHALL IS EXPECTED TO ENCOUNTER WARM NOSE ALOFT FROM
800-700 MB...BUT WITH SUB FREEZING TEMPERATURES AT THE SURFACE FALL
AS FREEZING RAIN. AS THE WARM LAYER GRADUALLY COOLS FROM
WEST...PRECIPITATION ALONG AND WEST OF THE JAMES RIVER VALLEY MAY
CHANGE OVER TO SNOW. SNOW SHOULD BE FAIRLY WET AND HEAVY...SO
DESPITE STRONG WINDS THINK THE MAIN THREAT WILL BE ICING AND SNOW AS
OPPOSED TO BLOWING SNOW. THEREFORE...AM GOING WINTER STORM WARNING
FOR COMBINATION OF SNOW AND ICING ISSUES THROUGH THE FORECAST
PERIOD.
ONCE THE PRECIPITATION BAND LIFTS TO THE NORTH...QUESTIONS START TO
ENTER INTO THE FORECAST. WITH LACK OF LARGE SCALE FORCING ACROSS
THE AREA...AM CONCERNED THAT PRECIPITATION MAY SHUT DOWN FOR A BULK
OF THE DAY ON TUESDAY. LARGE SCALE SUBSIDENCE ALOFT LEADS MID LEVEL
DRYING TO THE POINT WHERE THE DENDRITIC LAYER REMAINS UNSATURATED.
WHAT IS VERY INTERESTING ARE MODEL SOUNDINGS ARE NEARLY CONVECTIVE
WITH STEEP LAPSE RATES ALOFT FROM NEAR 800 MB WITH LITTLE CAPPING.
IF CONVECTIVE POTENTIAL REMAINS UNREALIZED...SHOULD BE LEFT WITH
AREAS OF DRIZZLE/FREEZING DRIZZLE UNTIL THE THE MAIN WAVE APPROACHES
TUESDAY EVENING. MODEL DIFFERENCES CONTINUE WITH TEMPERATURE
PROFILES. GFS CONTINUES TO BE MORE AGGRESSIVE WITH COLD AIR THAN
NAM...RESULTING IN SNOW FORECAST 50-70 MILES FURTHER TO THE EAST
THAN THE NAM. NAM LEADS TO A FAIRLY BROAD AREA WITHIN 30-40 MILES
EAST/WEST OF ICE FROM LAKE ANDES THROUGH BROOKINGS. STILL HAVE AXIS
WITHIN THE SAME REGION FOR HEAVIEST ICING POTENTIAL...WITH ICE
AMOUNTS UP TO A THIRD OF AN INCH OF ICE. IF THIS ICE WERE TO BECOME
A REALITY...THERE IS A SIGNIFICANT CONCERN WITH THE STRONG WIND OF
THE IMPACT IT WOULD HAVE WITH POWER LINES AND TREES ACROSS THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 351 PM CDT MON APR 8 2013
AS COLDER AIR WORKS IN ALOFT...EXPECT PRECIPITATION TO CHANGE OVER
TO SNOW TUESDAY NIGHT INTO WEDNESDAY ACROSS THE AREA. HEAVIEST
PRECIPITATION SHOULD BE EXPECTED ACROSS THE AREA TUESDAY NIGHT WITH
UPPER WAVE MOVING THROUGH...AND THEN THE TROWAL SETTING UP ON
WEDNESDAY INTO THURSDAY.
SYSTEM PULLING OUT A LITTLE SLOWER...SO WILL LINGER A CHANCE OF
LIGHT SNOW INTO THURSDAY...ESPECIALLY ACROSS OUR EAST. POTENTIALLY
COULD SEE ANOTHER INCH OR TWO IN NORTHEAST PARTS OF THE CWA INTO
THIS PERIOD. BRIEF BREAK IN PRECIP STILL LOOKS OK BETWEEN WAVES
FRIDAY/FRIDAY NIGHT...AND IF ECMWF IS CORRECT THIS BREAK COULD
EXTEND INTO THE WEEKEND AS WELL...AS THIS MODEL IS SLOWER THAN
GFS/GEM WITH NEXT NORTHERN STREAM WAVE TO AFFECT THE AREA. HOWEVER
GIVEN UNCERTAINTY WITH TIMING WILL KEEP LOW POPS STARTING WITH A
SLIGHT CHANCE SATURDAY...THEN GENERALLY LOW TO MID CHANCE RANGE
SATURDAY NIGHT THROUGH MONDAY.
TEMPERATURES ARE ANOTHER ISSUE THROUGH THE EXTENDED. TEMPERATURE
CONSENSUS FORECAST SEEMS TO BE WEIGHTED TOWARD NUMERICAL GUIDANCE
WHICH TRENDS TOWARD MUCH WARMER CLIMATOLOGY. HOWEVER...RAW MODEL
GUIDANCE REMAINS ON THE COOL SIDE OF NORMAL THROUGHOUT THE PERIOD
AND HAVE HEDGED TEMPERATURES DOWN A FEW DEGREES TO ACCOUNT FOR THIS.
UNFORTUNATELY...THIS INTRODUCES POTENTIAL FOR RAIN/SNOW MIX AT TIMES
ACROSS OUR NORTHERN CWA WITH ANY PRECIPITATION THROUGH WEEKEND INTO
MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 646 PM CDT MON APR 8 2013
WIDESPREAD IFR CEILINGS CAN BE EXPECTED THROUGH 00Z WEDNESDAY.
FREEZING RAIN AND SLEET WILL DEVELOP DURING THE NIGHT WEST OF YKN-
FSD-MML WITH RAIN TO THE EAST. THE RAIN WILL CHANGE OVER TO SNOW
WEST OF A BKX-PKS LINE AFTER 12Z TUESDAY...WITH RAIN...FREEZING
RAIN OR SLEET TO THE EAST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM CDT TUESDAY FOR SDZ062-
066-067-069-070.
WINTER STORM WARNING UNTIL 7 PM CDT WEDNESDAY FOR SDZ038>040-
053>056-059>061-065-068.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR SDZ062-066-067-069-070.
WINTER STORM WARNING UNTIL 1 PM CDT WEDNESDAY FOR SDZ050-052-057-
058-063-064.
MN...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM CDT TUESDAY FOR MNZ098.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR MNZ098.
WINTER STORM WARNING FROM 1 AM TUESDAY TO 7 PM CDT WEDNESDAY FOR
MNZ071-072-080-097.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1233 PM CDT SUN APR 7 2013
.AVIATION...
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE NEXT 24 HOURS. THE
MAIN AVIATION CONCERNS WILL BE THE POTENTIAL FOR STORMS TO DEVELOP
NEAR KGUY AND WIND SHIFTS AT ALL TERMINALS. THE THREAT FOR STORMS AT
KGUY REMAINS TOO LOW TO MENTION IN PREVAILING AND IS BECOMING
INCREASINGLY LESS LIKELY GIVEN THE STRONG CAP ACROSS THE WESTERN
OKLAHOMA PANHANDLE. STORMS SHOULD REMAIN WELL AWAY FROM KAMA AND
KDHT. THERE AREA COUPLE OF WIND SHIFTS THROUGHOUT THE TAF BUT FOR THE
MOST PART WINDS WILL REMAIN LESS THAN 12 KTS.
&&
.PREV DISCUSSION... /ISSUED 1159 AM CDT SUN APR 7 2013/
UPDATE...
OVERALL...CHANCE OF STRONG TO SEVERE STORMS DEVELOPING STILL EXISTS
FOR THE EASTERN OKLAHOMA AND NORTHEASTERN TEXAS PANHANDLE BUT THESE
CHANCES ARE BECOMING LESS LIKELY.
STRONG CAPPING IS STILL EXPECTED TO PERSIST UNTIL 3 PM...WEAKEN
BETWEEN 3 PM TO 9 PM...AND THEN STRENGTHEN AGAIN AFTER 9 PM. AS SUCH
THE ADVERTISED 4 PM TO 9 PM TIME FRAME REMAINS VALID FOR ANY STRONG
TO SEVERE STORMS TO FORM. RECENT RUC HRRR AND TTU WRF RUNS HAVE
SHOWN A NORTH AND EAST SHIFT IN HIGHER MLCAPE VALUES FAVORING EAST
OF A DODGE CITY TO TX/OK STATE BORDER LINE. AS A RESULT THE NE TX
AND E OK PANHANDLE RANGES BETWEEN 500-1000 J/KG OF MLCAPE WITH THE
HIGHER VALUES IN THE EASTERN EXTREMES OF THE CWA. HOWEVER...SHORT
RANGE MODEL SURFACE DEWPOINTS REMAIN A FEW DEGREES TOO HIGH COMPARED
TO SURFACE OBSERVATIONS SO CAPE VALUES...SPECIFICALLY SURFACE BASED
VALUES...MAY BE A LITTLE OVERDONE. SO STORMS MAY INITIATE OVER THE
EXTREME EASTERN TX/OK PANHANDLE THIS AFTERNOON AND EVENING BUT THE
LIKELIHOOD OF THESE STORMS BECOMING STRONG TO SEVERE IN OUR FORECAST
AREA HAS DECREASED.
PREV DISCUSSION... /ISSUED 615 AM CDT SUN APR 7 2013/
AVIATION...
FOR THE 12Z TAFS...SFC DRYLINE AND RESIDUAL FRONTAL BOUNDARY ARE
EXPECTED TO MOVE INTO ERN SECTIONS OF FCST AREA TODAY. IF ANY
THUNDERSTORMS DEVELOP LATE THIS AFTERNOON AND EVENING...THEY SHOULD
REMAIN ISOLD AT BEST AND SHOULD NOT AFFECT KDHT OR KAMA. LOW
CONFIDENCE AS TO WHETHER OR NOT ANY STORMS WILL AFFECT KGUY SO HAVE
OPTED TO LEAVE OUT OF THIS TAF FCST ISSUANCE. OTHERWISE...PERIODS OF
MID AND HIGH LEVEL CLOUDS ANTICIPATED THROUGH 12Z MONDAY.
ANDRADE
PREV DISCUSSION... /ISSUED 331 AM CDT SUN APR 7 2013/
DISCUSSION...
AN ACTIVE...ALBEIT MOSTLY DRY...WEATHER PATTERN IS ON TAP FOR THE
REGION FOR THE NEXT WEEK.
TODAY AND TONIGHT...THE FOCUS IS ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS LATE THIS AFTERNOON INTO THIS EVENING OVER THE OKLAHOMA
AND NORTHERN AND EASTERN TEXAS PANHANDLES. THE BIGGEST QUESTION IS
IF STORMS WILL EVEN DEVELOP. SURFACE AND LOW LEVEL CONFLUENCE ALONG A
WARM FRONT AND DRYLINE WILL NEED TO BE JUXTAPOSED WITH MEAGER MID AND
UPPER LEVEL SUPPORT AS A SMALL SHORTWAVE TROUGH SLIDES E OVER THE OK
PANHANDLE LATE TODAY. THIS IS FAR FROM A SURE THING AS MANY OF THE
SHORTER RANGE MODELS SHOW THE CENTER OF THE SURFACE LOW IN THE SW TX
PANHANDLE...WITH THE FRONT AND DRYLINE FEATURES WELL SOUTH OF THE
EXPECTED TRACK OF THE MID AN UPPER LEVEL TROUGH. IF THIS IS THE
CASE...AM NOT CONVINCED THAT THE LOW LEVEL CONFLUENCE IS ENOUGH TO
OVERCOME THE STRONG CAP. ADDITIONALLY...STILL CONCERNED THAT MODELS
ARE TOO AGGRESSIVE WITH LOW LEVEL MOISTURE RETURN. AT 08Z...UPSTREAM
OBS SHOW DEWPOINT TEMPERATURES GENERALLY IN THE40S AND 50S...BUT THE
NAM AND OTHER HIGH RESOLUTION MODELS SHOW A SURGE OF 60 OR HIGHER DEW
POINT TEMPERATURES BY 21Z. CAN/T SEE HOW WE WOULD HAVE THAT MUCH
MOISTURE ADVECTION IN SUCH A SHORT PERIOD OF TIME. HOWEVER IF STORMS
CAN DEVELOP...THERE IS A RISK THAT THEY WILL BECOME SEVERE. AS FOR
THE SEVERE THREATS...
HAIL SHOULD BE THE MAIN THREAT. MODEL SOUNDINGS SHOW ML CAPE VALUES
NEAR OR ABOVE 1000 J/KG. MUCH OF THAT IS IN THE HAIL GROWTH REGION.
IN ADDITION...BULK SHEAR VALUES...WHILE NOT AS HIGH AS WE/VE SEEN
WITH SOME OF THE SEVERE EVENTS LATELY...SHOULD STILL BE NEAR 40
KT...PLENTY ENOUGH TO SUPPORT SUSTAINED UPDRAFTS.
WIND...FOR A CHANGE THE WIND THREAT...WHILE NOT ZERO...IS LOWER
THAN THE HAIL THREAT. THE LOW AND MID LEVEL JETS SHOULD BE WELL EAST
OF THE REGION. THUS ANY STRONG WINDS WOULD EITHER HAVE TO BE MIXED
DOWN FROM THE UPPER LEVELS...OR WOULD HAVE TO SEE A DOWNBURST
ENHANCED BY PRECIPITATION LOADING.
TORNADO...THE TORNADO THREAT IS MINIMAL. THE MAIN REASONS IT IS SO
LOW IS MINIMAL HELICITY VALUES...HIGH LCL HEIGHTS...AND MODEST BULK
SHEAR VALUES...AND MOSTLY SPEED SHEAR AT THAT. HOWEVER...IT SHOULD BE
NOTED THAT THERE COULD BE SOME ENHANCED DIRECTIONAL SHEAR ALONG THE
BOUNDARIES BUT GIVEN THE WEST TO EAST STORM MOTIONS...DO NOT EXPECT
STORMS TO REMAIN CONNECTED TO EITHER THE FRONT OR DRY LINE FOR VERY
LONG.
FLOODING...FLOODING THREAT IS ALSO MINIMAL. THOUGH STORM MOTIONS WILL
BE RELATIVELY LOW...GENERALLY 15KT OR LESS...PRECIPITABLE WATER
VALUES ARE ONLY EXPECTED TO BE SLIGHTLY ABOVE NORMAL. IN
ADDITION...STORM MOTIONS AND BOUNDARY POSITIONS ARE NOT FAVORABLE FOR
TRAINING...AND GIVEN LIMITED COVERAGE DO NOT EXPECT MULTIPLE STORMS
TO MOVE OVER THE SAME LOCATIONS.
MONDAY...STILL LOOKING AT A WINDY DAY MAINLY DU TO INCREASING MID AND
UPPER LEVEL HEIGHT GRADIENTS AS THE MAIN TROUGH SLIDES INTO THE FOUR
CORNERS REGION. A COMBINATION OF A THICK CIRRUS DECK LIMITING
MIXING...AND A LATE DEVELOPMENT OF THE TIGHTEST HEIGHT AND PRESSURE
GRADIENTS WILL MEAN THAT WHILE IT WILL BE WINDY...WE WILL LIKELY STAY
BELOW WIND ADVISORY CRITERIA.
TUESDAY...THE MAIN STORY ON THIS DAY WILL BE THE COLD FRONT. THE
BIGGEST SOURCE OF UNCERTAINTY IS THE TIMING OF THE FRONT. WITH THE
00Z RUNS...THERE WAS RATHER GOOD AGREEMENT ON THE TIMING OF THE
FRONT...ARRIVING IN AMA BETWEEN 21 AND 00Z...BUT RATHER POOR RUN TO
RUN CONSISTENCY...AS THIS IS A BIT FASTER THAN THE 12Z RUNS. SOME
THINGS OF NOTE WITH THIS FRONT...FIRST...MODELS SHOW LARGE PRESSURE
RISES...ALMOST UNBELIEVABLY LARGE PRESSURE RISES...BEHIND THE
FRONT. THIS SHOULD LEAD STRONG POST FRONTAL WINDS...POSSIBLY NEAR
WIND ADVISORY. SECOND...THOUGH THE MAIN MID AND UPPER LEVEL TROUGH IS
QUICKLY LIFTING NE AT THIS TIME...LEAVING THE PANHANDLES IN A PRIME
LOCATION FOR THE DRY SLOT...SOME MODELS...MOST NOTABLY THE
ECMWF...CONTINUE TO SHOW PRECIPITATION BEHIND THE FRONT. IF ANY
PRECIP CAN DEVELOP...EXPECT THAT IT WILL BE THE RESULT OF RATHER
SHALLOW ISENTROPIC LIFT. THUS...EXPECT ONLY VERY LIGHT...IF
ANY...PRECIP.
WEDNESDAY THROUGH SUNDAY...REGION SHOULD SEE A RETURN TO A MORE ZONAL
FLOW PATTERN. FIRST A LEE SIDE SURFACE TROUGH IS EXPECTED TO DEVELOP
BY THURSDAY BRINGING A QUICK WARMING TREND. THERE COULD BE A FEW
EMBEDDED UPPER LEVEL SHORTWAVE TROUGHS TOWARDS THE END OF THE
WEEK...BUT UNCERTAINTY IN TIMING AND TRACK IS VERY HIGH AT THIS TIME.
JOHNSON
FIRE WEATHER...
DESPITE RELATIVE HUMIDITY VALUES NEAR OR BELOW 15 PERCENT...DO NOT
EXPECT ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS DUE TO RELATIVELY
LIGHT WINDS. ON MONDAY...CRITICAL FIRE WEATHER CONDITIONS ARE
POSSIBLE OVER THE WESTERN TEXAS PANHANDLE AND ELEVATED FIRE WEATHER
CONDITIONS ARE POSSIBLE ACROSS MUCH OF THE REST OF THE PANHANDLES DUE
TO SOUTHWESTERLY WINDS OF 15 TO 25 MPH...AND RELATIVE HUMIDITY VALUES
BETWEEN 10 AND 20 PERCENT. A COLD FRONT IS EXPECTED ON
TUESDAY...BRINGING AN ABRUPT SHIFT TO STRONG NORTHERLY WINDS.
DEPENDING ON HOW LATE IN THE DAY IT ARRIVES...ELEVATED TO NEAR
CRITICAL FIRE WEATHER CONDITIONS MAY BE POSSIBLE ACROSS THE SOUTHERN
TEXAS PANHANDLE.
JOHNSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
14/09
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1159 AM CDT SUN APR 7 2013
.UPDATE...
OVERALL...CHANCE OF STRONG TO SEVERE STORMS DEVELOPING STILL EXISTS
FOR THE EASTERN OKLAHOMA AND NORTHEASTERN TEXAS PANHANDLE BUT THESE
CHANCES ARE BECOMING LESS LIKELY.
STRONG CAPPING IS STILL EXPECTED TO PERSIST UNTIL 3 PM...WEAKEN
BETWEEN 3 PM TO 9 PM...AND THEN STRENGTHEN AGAIN AFTER 9 PM. AS SUCH
THE ADVERTISED 4 PM TO 9 PM TIME FRAME REMAINS VALID FOR ANY STRONG
TO SEVERE STORMS TO FORM. RECENT RUC HRRR AND TTU WRF RUNS HAVE
SHOWN A NORTH AND EAST SHIFT IN HIGHER MLCAPE VALUES FAVORING EAST
OF A DODGE CITY TO TX/OK STATE BORDER LINE. AS A RESULT THE NE TX
AND E OK PANHANDLE RANGES BETWEEN 500-1000 J/KG OF MLCAPE WITH THE
HIGHER VALUES IN THE EASTERN EXTREMES OF THE CWA. HOWEVER...SHORT
RANGE MODEL SURFACE DEWPOINTS REMAIN A FEW DEGREES TOO HIGH COMPARED
TO SURFACE OBSERVATIONS SO CAPE VALUES...SPECIFICALLY SURFACE BASED
VALUES...MAY BE A LITTLE OVERDONE. SO STORMS MAY INITIATE OVER THE
EXTREME EASTERN TX/OK PANHANDLE THIS AFTERNOON AND EVENING BUT THE
LIKELIHOOD OF THESE STORMS BECOMING STRONG TO SEVERE IN OUR FORECAST
AREA HAS DECREASED.
&&
.PREV DISCUSSION... /ISSUED 615 AM CDT SUN APR 7 2013/
AVIATION...
FOR THE 12Z TAFS...SFC DRYLINE AND RESIDUAL FRONTAL BOUNDARY ARE
EXPECTED TO MOVE INTO ERN SECTIONS OF FCST AREA TODAY. IF ANY
THUNDERSTORMS DEVELOP LATE THIS AFTERNOON AND EVENING...THEY SHOULD
REMAIN ISOLD AT BEST AND SHOULD NOT AFFECT KDHT OR KAMA. LOW
CONFIDENCE AS TO WHETHER OR NOT ANY STORMS WILL AFFECT KGUY SO HAVE
OPTED TO LEAVE OUT OF THIS TAF FCST ISSUANCE. OTHERWISE...PERIODS OF
MID AND HIGH LEVEL CLOUDS ANTICIPATED THROUGH 12Z MONDAY.
ANDRADE
PREV DISCUSSION... /ISSUED 331 AM CDT SUN APR 7 2013/
DISCUSSION...
AN ACTIVE...ALBEIT MOSTLY DRY...WEATHER PATTERN IS ON TAP FOR THE
REGION FOR THE NEXT WEEK.
TODAY AND TONIGHT...THE FOCUS IS ON THE POTENTIAL FOR SEVERE
THUNDERSTORMS LATE THIS AFTERNOON INTO THIS EVENING OVER THE OKLAHOMA
AND NORTHERN AND EASTERN TEXAS PANHANDLES. THE BIGGEST QUESTION IS
IF STORMS WILL EVEN DEVELOP. SURFACE AND LOW LEVEL CONFLUENCE ALONG A
WARM FRONT AND DRYLINE WILL NEED TO BE JUXTAPOSED WITH MEAGER MID AND
UPPER LEVEL SUPPORT AS A SMALL SHORTWAVE TROUGH SLIDES E OVER THE OK
PANHANDLE LATE TODAY. THIS IS FAR FROM A SURE THING AS MANY OF THE
SHORTER RANGE MODELS SHOW THE CENTER OF THE SURFACE LOW IN THE SW TX
PANHANDLE...WITH THE FRONT AND DRYLINE FEATURES WELL SOUTH OF THE
EXPECTED TRACK OF THE MID AN UPPER LEVEL TROUGH. IF THIS IS THE
CASE...AM NOT CONVINCED THAT THE LOW LEVEL CONFLUENCE IS ENOUGH TO
OVERCOME THE STRONG CAP. ADDITIONALLY...STILL CONCERNED THAT MODELS
ARE TOO AGGRESSIVE WITH LOW LEVEL MOISTURE RETURN. AT 08Z...UPSTREAM
OBS SHOW DEWPOINT TEMPERATURES GENERALLY IN THE40S AND 50S...BUT THE
NAM AND OTHER HIGH RESOLUTION MODELS SHOW A SURGE OF 60 OR HIGHER DEW
POINT TEMPERATURES BY 21Z. CAN/T SEE HOW WE WOULD HAVE THAT MUCH
MOISTURE ADVECTION IN SUCH A SHORT PERIOD OF TIME. HOWEVER IF STORMS
CAN DEVELOP...THERE IS A RISK THAT THEY WILL BECOME SEVERE. AS FOR
THE SEVERE THREATS...
HAIL SHOULD BE THE MAIN THREAT. MODEL SOUNDINGS SHOW ML CAPE VALUES
NEAR OR ABOVE 1000 J/KG. MUCH OF THAT IS IN THE HAIL GROWTH REGION.
IN ADDITION...BULK SHEAR VALUES...WHILE NOT AS HIGH AS WE/VE SEEN
WITH SOME OF THE SEVERE EVENTS LATELY...SHOULD STILL BE NEAR 40
KT...PLENTY ENOUGH TO SUPPORT SUSTAINED UPDRAFTS.
WIND...FOR A CHANGE THE WIND THREAT...WHILE NOT ZERO...IS LOWER
THAN THE HAIL THREAT. THE LOW AND MID LEVEL JETS SHOULD BE WELL EAST
OF THE REGION. THUS ANY STRONG WINDS WOULD EITHER HAVE TO BE MIXED
DOWN FROM THE UPPER LEVELS...OR WOULD HAVE TO SEE A DOWNBURST
ENHANCED BY PRECIPITATION LOADING.
TORNADO...THE TORNADO THREAT IS MINIMAL. THE MAIN REASONS IT IS SO
LOW IS MINIMAL HELICITY VALUES...HIGH LCL HEIGHTS...AND MODEST BULK
SHEAR VALUES...AND MOSTLY SPEED SHEAR AT THAT. HOWEVER...IT SHOULD BE
NOTED THAT THERE COULD BE SOME ENHANCED DIRECTIONAL SHEAR ALONG THE
BOUNDARIES BUT GIVEN THE WEST TO EAST STORM MOTIONS...DO NOT EXPECT
STORMS TO REMAIN CONNECTED TO EITHER THE FRONT OR DRY LINE FOR VERY
LONG.
FLOODING...FLOODING THREAT IS ALSO MINIMAL. THOUGH STORM MOTIONS WILL
BE RELATIVELY LOW...GENERALLY 15KT OR LESS...PRECIPITABLE WATER
VALUES ARE ONLY EXPECTED TO BE SLIGHTLY ABOVE NORMAL. IN
ADDITION...STORM MOTIONS AND BOUNDARY POSITIONS ARE NOT FAVORABLE FOR
TRAINING...AND GIVEN LIMITED COVERAGE DO NOT EXPECT MULTIPLE STORMS
TO MOVE OVER THE SAME LOCATIONS.
MONDAY...STILL LOOKING AT A WINDY DAY MAINLY DU TO INCREASING MID AND
UPPER LEVEL HEIGHT GRADIENTS AS THE MAIN TROUGH SLIDES INTO THE FOUR
CORNERS REGION. A COMBINATION OF A THICK CIRRUS DECK LIMITING
MIXING...AND A LATE DEVELOPMENT OF THE TIGHTEST HEIGHT AND PRESSURE
GRADIENTS WILL MEAN THAT WHILE IT WILL BE WINDY...WE WILL LIKELY STAY
BELOW WIND ADVISORY CRITERIA.
TUESDAY...THE MAIN STORY ON THIS DAY WILL BE THE COLD FRONT. THE
BIGGEST SOURCE OF UNCERTAINTY IS THE TIMING OF THE FRONT. WITH THE
00Z RUNS...THERE WAS RATHER GOOD AGREEMENT ON THE TIMING OF THE
FRONT...ARRIVING IN AMA BETWEEN 21 AND 00Z...BUT RATHER POOR RUN TO
RUN CONSISTENCY...AS THIS IS A BIT FASTER THAN THE 12Z RUNS. SOME
THINGS OF NOTE WITH THIS FRONT...FIRST...MODELS SHOW LARGE PRESSURE
RISES...ALMOST UNBELIEVABLY LARGE PRESSURE RISES...BEHIND THE
FRONT. THIS SHOULD LEAD STRONG POST FRONTAL WINDS...POSSIBLY NEAR
WIND ADVISORY. SECOND...THOUGH THE MAIN MID AND UPPER LEVEL TROUGH IS
QUICKLY LIFTING NE AT THIS TIME...LEAVING THE PANHANDLES IN A PRIME
LOCATION FOR THE DRY SLOT...SOME MODELS...MOST NOTABLY THE
ECMWF...CONTINUE TO SHOW PRECIPITATION BEHIND THE FRONT. IF ANY
PRECIP CAN DEVELOP...EXPECT THAT IT WILL BE THE RESULT OF RATHER
SHALLOW ISENTROPIC LIFT. THUS...EXPECT ONLY VERY LIGHT...IF
ANY...PRECIP.
WEDNESDAY THROUGH SUNDAY...REGION SHOULD SEE A RETURN TO A MORE ZONAL
FLOW PATTERN. FIRST A LEE SIDE SURFACE TROUGH IS EXPECTED TO DEVELOP
BY THURSDAY BRINGING A QUICK WARMING TREND. THERE COULD BE A FEW
EMBEDDED UPPER LEVEL SHORTWAVE TROUGHS TOWARDS THE END OF THE
WEEK...BUT UNCERTAINTY IN TIMING AND TRACK IS VERY HIGH AT THIS TIME.
JOHNSON
FIRE WEATHER...
DESPITE RELATIVE HUMIDITY VALUES NEAR OR BELOW 15 PERCENT...DO NOT
EXPECT ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS DUE TO RELATIVELY
LIGHT WINDS. ON MONDAY...CRITICAL FIRE WEATHER CONDITIONS ARE
POSSIBLE OVER THE WESTERN TEXAS PANHANDLE AND ELEVATED FIRE WEATHER
CONDITIONS ARE POSSIBLE ACROSS MUCH OF THE REST OF THE PANHANDLES DUE
TO SOUTHWESTERLY WINDS OF 15 TO 25 MPH...AND RELATIVE HUMIDITY VALUES
BETWEEN 10 AND 20 PERCENT. A COLD FRONT IS EXPECTED ON
TUESDAY...BRINGING AN ABRUPT SHIFT TO STRONG NORTHERLY WINDS.
DEPENDING ON HOW LATE IN THE DAY IT ARRIVES...ELEVATED TO NEAR
CRITICAL FIRE WEATHER CONDITIONS MAY BE POSSIBLE ACROSS THE SOUTHERN
TEXAS PANHANDLE.
JOHNSON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
14/09
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1226 PM CDT SUN APR 7 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN APR 7 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED UPPER TROUGHING APPROACHING THE PACIFIC
NORTHWEST...WEAK RIDGING OVER THE NORTHERN U.S. ROCKIES INTO THE
DAKOTAS...AND A SHORTWAVE TROUGH OVER EASTERN WISCONSIN. ALSO OF
NOTE ON WATER VAPOR WERE A PAIR OF SHORTWAVES MOVING THROUGH THE
WEAK RIDGING...ONE IN SOUTH CENTRAL WYOMING AND THE OTHER IN
NORTHWEST COLORADO. THE FORECAST AREA LIES IN SUBSIDENCE IN THE
WAKE OF THE EASTERN WISCONSIN SHORTWAVE TROUGH...SEEN AS AN
INVERSION BETWEEN 775 AND 850MB ON THE 00Z MPX SOUNDING. THIS
INVERSION WAS ALSO SATURATED... REFLECTED TOO BY PLENTY OF STRATUS
CLOUDS ON 11-3.9UM IMAGERY FROM THE EASTERN DAKOTAS INTO THE
FORECAST AREA. COOLER AIR HAS BEEN FILTERING IN BEHIND THE
SHORTWAVE AS WELL WITH 850MB TEMPS NOW DOWN TO +2 TO -3C ACROSS
THE FORECAST AREA PER RAP ANALYSIS...COLDEST OVER CENTRAL
WISCONSIN. AT THE SURFACE...HIGH PRESSURE WAS SEEN DROPPING SOUTH
INTO WESTERN MINNESOTA...IN THE WAKE OF LOW PRESSURE OVER NORTHERN
LAKE MICHIGAN AND ITS COLD FRONT WHICH EXTENDS SOUTHWEST TO KANSAS
CITY.
A PATTERN CHANGE IS FORECAST TO OCCUR ALOFT DURING THE NEXT 24 HOURS
AS THE UPPER TROUGH SEEN OFF THE PACIFIC NORTHWEST SHARPLY DIGS
SOUTH INTO CALIFORNIA AND NEVADA. IN RESPONSE...RIDGING WILL BUILD
DOWNSTREAM...ADJUSTING THE UPPER LEVEL FLOW TO SOUTHWESTERLY OVER
THE FORECAST AREA. THIS MEANS THAT THE RECENT LOW LEVEL COLD
ADVECTION WILL COME TO AN END SHORTLY...WITH WARM ADVECTION PROGGED
TO BEGIN BETWEEN 12-18Z TODAY AND CONTINUE THROUGH TONIGHT. IN
ADDITION...MODELS HAVE BEEN CONSISTENT IN SHOWING THE PAIR OF
SHORTWAVES SEEN IN WYOMING AND COLORADO TO AFFECT THE FORECAST AREA
LATE TONIGHT AS THEY RIDE THROUGH THE SOUTHWEST FLOW.
THE FIRST TWO ISSUES FOR THE SHORT TERM PERIOD ARE THE CLOUDS AND
HIGH TEMPERATURES TODAY. THE PRESENT STRATUS DECK DOES HAVE SOME
HOLES IN IT ON ITS SOUTHERN SIDE. THESE HOLES SHOULD EXPAND THROUGH
THE MORNING AS DIURNAL MIXING COMMENCES. 07.00Z NAM LOW LEVEL RH
FIELDS...WHICH GENERALLY TEND PESSIMISTIC...ALSO SUGGEST THAT THE
STRATUS DECK WILL MOSTLY MIX OUT BY 18Z SOUTH OF US HIGHWAY 10.
LATER IN THE AFTERNOON...SAY 21Z AND AFTER...MID AND HIGH CLOUDS
CURRENTLY SPREADING INTO THE PLAINS STATES ARE PROGGED TO MOVE INTO
THE FORECAST AREA. THUS WE SHOULD SEE AT LEAST A FEW HOURS OF MOSTLY
SUNNY SKIES TODAY. WITH 850MB TEMPS CLIMBING TO 0C NORTH AND 6C
SOUTH BY 18Z...ANTICIPATING THAT MOST LOCATIONS MINUS NORTH OF
HIGHWAY 10 WHERE MORE CLOUDS AND SNOW EXIST WILL CLIMB INTO THE 50S.
WARMEST TEMPERATURES...APPROACHING 60...ARE EXPECTED IN THE FAR
SOUTH.
THE NEXT ISSUE FOR THE SHORT TERM PERIOD IS THE POTENTIAL FOR
PRECIPITATION VERY LATE THIS AFTERNOON INTO TONIGHT...DUE TO THE
WARM ADVECTION PATTERN AND THE APPROACH OF THE PAIR OF SHORTWAVES.
THE 07.00Z GFS/06.12Z ECMWF ALREADY SHOW HINTS OF WARM ADVECTION /
ISENTROPICALLY INDUCED PRECIPITATION AFFECTING FAR WESTERN PORTIONS
OF THE FORECAST AREA BETWEEN 21-00Z TODAY. THINKING THIS MIGHT BE A
BIT FAST...WITH THE 07.00Z NAM/REGIONAL CANADIAN/HIRES-ARW AND
07.03Z SREF ALL SLOWER. THUS...PLAN ON KEEPING CONDITIONS DRY TIL
00Z. AS WE HEAD THROUGH TONIGHT...THERE IS A STRONG CONSENSUS
AMONGST ALL MODEL GUIDANCE OF A PRECIPITATION SPLIT. THE NORTHERN
AREA TRACKS FROM NORTHWEST IA/SOUTHERN MN INTO NORTHWEST
WISCONSIN. THE SOUTHERN AREA TRACKS FROM NORTHERN MISSOURI INTO
SOUTHEAST IA AND NORTHWEST IL. THIS SPLIT APPEARS TO BE A RESULT
OF HOW THE PAIR OF SHORTWAVES APPROACHING THE FORECAST AREA LATE
TONIGHT INTERACT WITH THE ISENTROPIC LIFT PATTERN IN PLACE. 850MB
MOISTURE TRANSPORT FIELDS SHOW THE SPLIT INTERACTION WITH THE
ISENTROPIC LIFT PATTERN NICELY. IN ADDITION...THERE ARE OTHER
SUPPORTING FEATURES. FOR EXAMPLE...THE NORTHERN AREA BECOMES
INFLUENECED BY A DEVELOPING AND STRENGTHENING UPPER JET STREAK
OVER UPPER MICHIGAN...PLACING IT IN THE FAVORABLE RIGHT ENTRANCE
REGION. MEANWHILE...THE SOUTHERN AREA HAS A STRONG LOW TO MID-
LEVEL FRONTOGENESIS FEATURE ALONG THE PRESENT COLD FRONT NEAR
I-70...WHICH FOR ALL INTENSIVE PUPROSES TURNS INTO A STATIONARY
BOUNDARY. SO FOR THE FORECAST...THIS WELL AGREED UPON SPLIT
PRECIPITATION SCENARIO POSES A PROBLEM FROM WHAT WE HAD GOING
PREVIOUSLY. HAVE ADJUSTED PRECIPITATION CHANCES AND QPF QUITE A
BIT LOWER SOUTH OF I-90...SINCE THIS AREA WILL BE ON THE SUBSIDENT
SIDE OF THE F-GEN CIRCULATION. NOTE THAT MODELS LIKE THE 07.00Z
GFS/REGIONAL CANADIAN EVEN SUGGEST THAT SOME LOCATIONS ACROSS
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN COULD END UP DRY.
REGARDING PRECIPITATION TYPE...ALL OF IT SHOULD FALL AS RAIN WITH
WET-BULB ZERO HEIGHTS PROGGED WELL ABOVE 2000 FT. THE PREVIOUS
FORECAST INTRODUCED A CHANCE FOR THUNDER AND THIS STILL LOOKS
REASONABLE AFTER MIDNIGHT...WITH POTENTIAL FOR A FEW HUNDERED J/KG
OF SKINNY CAPE LIFTED FROM 850MB.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN APR 7 2013
OVERALL MUCH OF THE LONG TERM PERIOD LOOKS ACTIVE...THANKS TO THAT
TROUGH DIGGING INTO CALIFORNIA AND NEVADA TONIGHT. QUITE A FEW
DETAILS TO NOTE.
ON MONDAY...THE PAIR OF SHORTWAVES ARE PROGGED TO SHIFT EAST INTO
MICHIGAN DURING THE AFTERNOON...TAKING THE BULK OF THE SPLIT
PRECIPITATION TONIGHT WITH THEM. HOWEVER...THE STORY DOES NOT END
THERE. THE FOCUS TURNS TO THE FRONTAL BOUNDARY NEAR I-70...WHICH BY
ALL MODELS IS SUGGESTED TO LIFT NORTH INTO CENTRAL AND PERHAPS
NORTHERN IA DURING THE AFTERNOON. THE LIFTING NORTH IS A RESULT OF
THE UPPER TROUGHING DEEPENING AND DIGGING INTO THE FOUR CORNERS
REGION...ENHANCING THE WARM ADVECTION DOWNSTREAM. THE 07.00Z
REGIONAL CANADIAN AND NAM SUGGEST THERE IS POTENTIAL FOR SURFACE
BASED CONVECTION TO FIRE ON THIS FRONT. THE 07.00Z GFS...ON THE
OTHER HAND...HAS A FARTHER SOUTH FRONT AND KEEPS THINGS MORE CAPPED.
HOWEVER...ALL THREE MODELS INCLUDING THE 06.12Z ECMWF DEPICT
POTENTIAL FOR FRONTOGENETICALY INDUCED PRECIPITATION NORTH OF THE
FRONTAL BOUNDARY. THUS...A NEED CONTINUES FOR CHANCES OF SHOWERS
ALONG WITH THE THUNDERSTORM MENTION IN THE EVENT THE REGIONAL
CANADIAN/NAM PAN OUT. IF THE REGIONAL CANADIAN/NAM PAN OUT...
CERTAINLY COULD NOT RULE OUT SOME SEVERE POTENTIAL GIVEN 0-6 KM
SHEAR UPWARS OF 45-50 KT. HOWEVER...IT SEEMS LIKE THE BETTER
INSTABILITY IS WEST OF THE FORECAST AREA...THUS KEEPING THE BULK OF
THE SEVERE POTENTIAL TO THE WEST. SPC DAY 2 SEVERE PROBABILITIES
DEPICT THIS AS WELL. DEFINITELY SOMETHING TO KEEP AN EYE
ON....THOUGH. TEMPERATURE FORECAST IS TRICKY AS IT DEPENDS ON THE
FRONTAL POSITION. A NAM/REGIONAL CANADIAN OR EVEN ECMWF SOLUTION
WOULD ALLOW FOR HIGHS IN THE 60S TO POSSIBLY 70 ALONG/SOUTH OF I-90.
THE GFS IS A LITTLE COOLER BUT STILL HAS HIGHS IN THE 60S SOUTH OF
I-90. RAISED HIGHS 5 DEGREES OR SO TO COME BETTER IN AGREEMENT WITH
ALL 07.00Z GUIDANCE...BUT THEY MAY NEED TO BE RAISED MORE...
ESPECIALLY IF MORE SUN OCCURS IN THE AFTERNOON.
THINGS GET MORE INTERESTING HEADING INTO THE MONDAY NIGHT THROUGH
THURSDAY TIME PERIOD. DURING THIS PERIOD...ALL MODELS HAVE THE DEEP
UPPER TROUGH OVER THE FOUR CORNERS SLOWLY LIFTING TO THE
EAST-NORTHEAST. MEANWHILE...AT THE SAME TIME THERE IS A DEEP UPPER
TROUGH HANGING AROUND THE HUDSON BAY INTO NORTHERN ONTARIO AREA...
HELPING TO HOLD AN UPPER JET STREAK IN PLACE OVER THE NORTHERN GREAT
LAKES. THIS MEANS THE FORECAST AREA IS GOING TO BE PLACED IN THE
FAVORABLE RIGHT ENTRANCE REGION UNTIL THE UPPER TROUGH MOVES IN.
MONDAY NIGHT FOR THE MOST PART LOOKS QUIET...WITH ANY SHOWERS AND
POSSIBLE THUNDERSTORMS IN THE EVENING DISSIPATING WITH LOSS OF
DAYTIME HEATING. THE FRONTAL BOUNDARY...IF IT IS NEARBY...LOOKS TO
SLOWLY DROP SOUTH MONDAY NIGHT FORCED BY THAT DEEP UPPER TROUGH TO
OUR NORTH. IT APPEARS THERE MAY BE A MASS OF LOW LEVEL STRATUS THAT
MOVES IN BEHIND THE FRONT...AND WITH LOW LEVEL FRONTOGENESIS BEHIND
THE FRONT WE COULD DEAL WITH SOME LIGHT RAIN OR DRIZZLE.
PRECIPITATION CHANCES DEFINITELY GO ON THE INCREASE FROM SOUTHWEST
TO NORTHEAST THROUGH THE DAY TUESDAY AND INTO TUESDAY NIGHT...IN
RESPONSE TO ISENTROPIC LIFT STRENGTHENING DOWNSTREAM OF THE UPPER
TROUGH PUSHING TO THE EAST-NORTHEAST. SOME CONCERN FOR SOME HEAVIER
RAIN TUESDAY NIGHT...ESPECIALLY ACROSS THE SOUTH...AS PRECIPITABLE
WATER VALUES INCREASE OVER 1 INCH AND SOME WEAK ELEVATED INSTABILITY
MOVES IN FOR THUNDERSTORMS. RAISED BOTH PRECIPITATION CHANCES AND
QPF FOR TUESDAY AND ESPECIALLY TUESDAY NIGHT GIVEN THE STRONG SIGNAL
AMONGST THE 07.00Z ECMWF/GFS/CANADIAN MODELS. FROM WEDNESDAY INTO
THURSDAY...THE CORE OF THE UPPER TROUGH IS PROGGED TO SLOWLY
APPROACH THE FORECAST AREA. AS THIS OCCURS...THE FORECAST AREA
EVENTUALLY ENDS UP ON THE NORTHWEST / COLD SIDE OF A SURFACE LOW
TRACKING TO OUR SOUTH...PLACING THE AREA INTO THE TROWAL AND COLD
CONVEYOR BELT REGION. GIVEN THE GOOD MODEL AGREEMENT AGAIN...RAISED
PRECIPITATION CHANCES UP DURING THIS PERIOD. IN ADDITION...WILL HAVE
TO WATCH FOR SOME SNOW ACCUMULATIONS COME WEDNESDAY NIGHT AND
THURSDAY AS 850MB TEMPS DROP TO -4 TO -8C BY 12Z THURSDAY.
IT SHOULD BE NOTED THAT THE 07.00Z NAM IS AN OUTLIER SOLUTION TO THE
ABOVE SCENARIO...PARTICULARLY FOR TUESDAY THROUGH WEDNESDAY...SINCE
IT EJECTS THE CORE OF THE SOUTHWESTERN TROUGH MUCH QUICKER AND LIFTS
IT FARTHER NORTH. THE NAM WAS DISCOUNTED GIVEN GOOD MODEL AGREEMENT
BETWEEN ALL OTHER MODELS. THE 07.03Z SREF LOOKS LIKE A COMPROMISE
BETWEEN THE NAM AND GFS...BUT THE SREF IS NAM-BIASED DUE TO AN
OVERWHELMING AMOUNT OF NAM MEMBERS. THUS...THE SREF WAS DISCOUNTED
AS WELL.
LOOKING FARTHER AHEAD...GOOD MODEL AGREEMENT EXISTS AMONGST THE
07.00Z ECMWF/GFS/CANADIAN ON BRINGING COLD CANADIAN HIGH PRESSURE
INTO THE AREA THURSDAY NIGHT THROUGH FRIDAY NIGHT. THIS SHOULD HELP
DRY THINGS OUT. LEFT A CONSENUS 20 PERCENT CHANCE OF PRECIPITATION
IN THURSDAY NIGHT...BUT THIS PERIOD MAY EVENTUALLY END UP DRY. WILL
NEED TO WATCH SOME OF THE LOW TEMPERATURES TOO FOR BOTH THURSDAY
NIGHT AND FRIDAY NIGHT...DEPENDING ON HOW MUCH FRESH SNOW WE PICK UP
AND FOR FRIDAY NIGHT HOW MUCH IS STILL ON THE GROUND. A WARM
ADVECTION PATTERN SETS UP FOR SATURDAY AHEAD OF NEW TROUGHING
DROPPING INTO THE NORTHERN ROCKIES. FOLLOWED THE CONSENSUS HERE OF
BRINGING SOME 20-30 PERCENT CHANCES OF PRECIPITATION ACROSS THE AREA
ON SATURDAY. NEED TO MAINTAIN A RAIN/SNOW MIX BECAUSE 850MB TEMPS
ARE STILL SLOW TO WARM...ESPECIALLY IN THE ECMWF WHERE IT KEEPS THEM
BELOW 0C THROUGH 00Z SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1226 PM CDT SUN APR 7 2013
MVFR STRATUS IN PLACE ACROSS THE REGION GOING INTO THIS AFTERNOON.
RAP/NAM BUFKIT SOUNDINGS INSIST THAT THIS STRATUS WILL DISPERSE
FROM SOUTH TO NORTH ACROSS THE AREA. LATEST VIS SATELLITE
LOOP...IN FACT...STARTING TO SHOW THIS TREND. BASED ON THIS...HAVE
KRST AND KLSE SCATTERING OUT IN THE 22-23Z TIME FRAME. THIS
CLEARING WILL BE SHORT-LIVED HOWEVER DUE TO VFR MID-CLOUD
SPREADING NORTHEAST OUT OF THE PLAINS AHEAD OF LOW PRESSURE
DEVELOPING OVER THE INTERMOUNTAIN WEST. LOOK FOR THE LOW TO SLOWLY
LIFT OUT OF THE INTERMOUNTAIN WEST INTO THE PLAINS TONIGHT INTO
MONDAY. THIS WILL LIFT A WARM FRONT NORTHEAST TOWARD THE AREA AND
PRODUCE SCATTERED/NUMEROUS SHOWERS LATER THIS EVENING THROUGH THE
OVERNIGHT HOURS. EXPECT DETERIORATING CLOUD CIGS AND VSBY INTO
MVFR/IFR RANGE AFTER 08Z...LASTING INTO MONDAY MORNING. MAY SEE
ENOUGH MID-LEVEL INSTABILITY FOR A FEW EMBEDDED THUNDERSTORMS
AFTER MIDNIGHT THROUGH MONDAY MORNING...BUT NOT CONFIDENT ENOUGH AT
THIS POINT TO INCLUDE IN THE BODY OF THE TAF.
&&
.HYDROLOGY...
ISSUED AT 342 AM CDT SUN APR 7 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH MONDAY MORNING.
MEANWHILE ON THE BLACK...ANOTHER BRIEF ICE JAM LOOKS LIKE IT MAY
HAVE FORMED AROUND NEILLSVILLE...WITH A SPIKE UP OF 4 FEET BUT STILL
WELL WITHIN THE RIVER BANK. DOWNSTREAM...SO FAR THE BLACK REMAINS
WITHIN THE RIVER BANK.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTHEAST OF THE INTERSTATE 94 CORRIDOR WITH 2 TO 7 INCHES OF
SNOW DEPTH IN PLACES. THE DEEPEST SNOW PACK IS OVER THE NORTHERN
MOST PARTS OF TAYLOR WHERE AROUND A FOOT OF SNOW REMAINS ON THE
GROUND. SNOW WATER EQUIVALENT OF 1 TO 2 INCHES IS MAINLY NORTH OF
THE INTERSTATE 94 CORRIDOR WITH THE GREATEST SNOW WATER EQUIVALENT
OF 2 TO 4 INCHES IN NORTHERN TAYLOR COUNTY.
RAINFALL...
LESS RAINFALL IS ANTICIPATED TONIGHT INTO MONDAY THAN PREVIOUSLY
EXPECTED...WITH UPWARDS OF 1/4 TO 1/2 INCH NORTH OF I-90 AND LESS
THAN A 1/4 INCH TO THE SOUTH. WILL STILL NEED TO WATCH TUESDAY
THROUGH WEDNESDAY...THOUGH. BY WEDNESDAY MORNING...CURRENTLY
ANTICIPATING AMOUNTS BETWEEN 3/4 INCH AND 1.25 INCHES SOUTH OF
HIGHWAY 10 TO LESS THAN A 1/2 INCH TO THE NORTH. IF THE SYSTEM
BRINGING THIS RAIN SHIFTS FARTHER NORTH...THE HEAVY RAIN AREA WILL
SHIFT NORTH AS WELL...PLACING IT WHERE RAIN IS NOT NEEDED.
TEMPERATURES...
HIGHS TODAY ARE GOING TO BE COOLER...IN THE THE MIDDLE 40S/AROUND 50
NORTH OF I-94 AND IN THE 50S SOUTH OF THERE. WARMER CONDITIONS LOOK
ON TAP FOR MONDAY...WITH MOSTLY 50S NORTH OF I-94 AND 60S SOUTH.
TEMPERATURES THEN COOL INTO THE 40S FOR TUESDAY AND WEDNESDAY AND
POSSIBLY STRUGGLE TO GET TO 40 BY THURSDAY. THE TEMPERATURE MAY NOT
MATTER IN A FEW DAYS AS MOST OF THE SNOW PACK MAY BE GONE...UNTIL
POTENTIALL A SMALL SNOW PACK RE-ESTABLISHES ITSELF THURSDAY MORNING.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING REMAINS ALONG THE TREMPEALEAU AND BLACK
RIVERS AS SNOW MELT CONTINUES...ALONG WITH THE PERIODS OF RAINFALL
TONIGHT INTO MONDAY AS WELL AS TUESDAY THROUGH WEDNESDAY. HAVE A
HYDROLOGIC OUTLOOK PRODUCT OUT TO HEIGHTEN THIS AWARENESS. ALTHOUGH
THE TUESDAY INTO WEDNESDAY MODERATE TO HEAVY RAIN IS FORECAST MAINLY
SOUTH OF I-90...CURRENTLY THINKING THAT THE RIVERS SHOULD BE ABLE TO
ABSORB IT. A QUICK MODEL OF THE TURKEY RIVER AT GARBER USING THE
FORECAST QPF WOULD BRING THE RIVER ABOVE ACTION STAGE BUT NOT TO
FLOOD. THUS...DID NOT EXPAND THE HYDROLOGIC OUTLOOK SOUTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
639 AM CDT SUN APR 7 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN APR 7 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED UPPER TROUGHING APPROACHING THE PACIFIC
NORTHWEST...WEAK RIDGING OVER THE NORTHERN U.S. ROCKIES INTO THE
DAKOTAS...AND A SHORTWAVE TROUGH OVER EASTERN WISCONSIN. ALSO OF
NOTE ON WATER VAPOR WERE A PAIR OF SHORTWAVES MOVING THROUGH THE
WEAK RIDGING...ONE IN SOUTH CENTRAL WYOMING AND THE OTHER IN
NORTHWEST COLORADO. THE FORECAST AREA LIES IN SUBSIDENCE IN THE
WAKE OF THE EASTERN WISCONSIN SHORTWAVE TROUGH...SEEN AS AN
INVERSION BETWEEN 775 AND 850MB ON THE 00Z MPX SOUNDING. THIS
INVERSION WAS ALSO SATURATED... REFLECTED TOO BY PLENTY OF STRATUS
CLOUDS ON 11-3.9UM IMAGERY FROM THE EASTERN DAKOTAS INTO THE
FORECAST AREA. COOLER AIR HAS BEEN FILTERING IN BEHIND THE
SHORTWAVE AS WELL WITH 850MB TEMPS NOW DOWN TO +2 TO -3C ACROSS
THE FORECAST AREA PER RAP ANALYSIS...COLDEST OVER CENTRAL
WISCONSIN. AT THE SURFACE...HIGH PRESSURE WAS SEEN DROPPING SOUTH
INTO WESTERN MINNESOTA...IN THE WAKE OF LOW PRESSURE OVER NORTHERN
LAKE MICHIGAN AND ITS COLD FRONT WHICH EXTENDS SOUTHWEST TO KANSAS
CITY.
A PATTERN CHANGE IS FORECAST TO OCCUR ALOFT DURING THE NEXT 24 HOURS
AS THE UPPER TROUGH SEEN OFF THE PACIFIC NORTHWEST SHARPLY DIGS
SOUTH INTO CALIFORNIA AND NEVADA. IN RESPONSE...RIDGING WILL BUILD
DOWNSTREAM...ADJUSTING THE UPPER LEVEL FLOW TO SOUTHWESTERLY OVER
THE FORECAST AREA. THIS MEANS THAT THE RECENT LOW LEVEL COLD
ADVECTION WILL COME TO AN END SHORTLY...WITH WARM ADVECTION PROGGED
TO BEGIN BETWEEN 12-18Z TODAY AND CONTINUE THROUGH TONIGHT. IN
ADDITION...MODELS HAVE BEEN CONSISTENT IN SHOWING THE PAIR OF
SHORTWAVES SEEN IN WYOMING AND COLORADO TO AFFECT THE FORECAST AREA
LATE TONIGHT AS THEY RIDE THROUGH THE SOUTHWEST FLOW.
THE FIRST TWO ISSUES FOR THE SHORT TERM PERIOD ARE THE CLOUDS AND
HIGH TEMPERATURES TODAY. THE PRESENT STRATUS DECK DOES HAVE SOME
HOLES IN IT ON ITS SOUTHERN SIDE. THESE HOLES SHOULD EXPAND THROUGH
THE MORNING AS DIURNAL MIXING COMMENCES. 07.00Z NAM LOW LEVEL RH
FIELDS...WHICH GENERALLY TEND PESSIMISTIC...ALSO SUGGEST THAT THE
STRATUS DECK WILL MOSTLY MIX OUT BY 18Z SOUTH OF US HIGHWAY 10.
LATER IN THE AFTERNOON...SAY 21Z AND AFTER...MID AND HIGH CLOUDS
CURRENTLY SPREADING INTO THE PLAINS STATES ARE PROGGED TO MOVE INTO
THE FORECAST AREA. THUS WE SHOULD SEE AT LEAST A FEW HOURS OF MOSTLY
SUNNY SKIES TODAY. WITH 850MB TEMPS CLIMBING TO 0C NORTH AND 6C
SOUTH BY 18Z...ANTICIPATING THAT MOST LOCATIONS MINUS NORTH OF
HIGHWAY 10 WHERE MORE CLOUDS AND SNOW EXIST WILL CLIMB INTO THE 50S.
WARMEST TEMPERATURES...APPROACHING 60...ARE EXPECTED IN THE FAR
SOUTH.
THE NEXT ISSUE FOR THE SHORT TERM PERIOD IS THE POTENTIAL FOR
PRECIPITATION VERY LATE THIS AFTERNOON INTO TONIGHT...DUE TO THE
WARM ADVECTION PATTERN AND THE APPROACH OF THE PAIR OF SHORTWAVES.
THE 07.00Z GFS/06.12Z ECMWF ALREADY SHOW HINTS OF WARM ADVECTION /
ISENTROPICALLY INDUCED PRECIPITATION AFFECTING FAR WESTERN PORTIONS
OF THE FORECAST AREA BETWEEN 21-00Z TODAY. THINKING THIS MIGHT BE A
BIT FAST...WITH THE 07.00Z NAM/REGIONAL CANADIAN/HIRES-ARW AND
07.03Z SREF ALL SLOWER. THUS...PLAN ON KEEPING CONDITIONS DRY TIL
00Z. AS WE HEAD THROUGH TONIGHT...THERE IS A STRONG CONSENSUS
AMONGST ALL MODEL GUIDANCE OF A PRECIPITATION SPLIT. THE NORTHERN
AREA TRACKS FROM NORTHWEST IA/SOUTHERN MN INTO NORTHWEST
WISCONSIN. THE SOUTHERN AREA TRACKS FROM NORTHERN MISSOURI INTO
SOUTHEAST IA AND NORTHWEST IL. THIS SPLIT APPEARS TO BE A RESULT
OF HOW THE PAIR OF SHORTWAVES APPROACHING THE FORECAST AREA LATE
TONIGHT INTERACT WITH THE ISENTROPIC LIFT PATTERN IN PLACE. 850MB
MOISTURE TRANSPORT FIELDS SHOW THE SPLIT INTERACTION WITH THE
ISENTROPIC LIFT PATTERN NICELY. IN ADDITION...THERE ARE OTHER
SUPPORTING FEATURES. FOR EXAMPLE...THE NORTHERN AREA BECOMES
INFLUENECED BY A DEVELOPING AND STRENGTHENING UPPER JET STREAK
OVER UPPER MICHIGAN...PLACING IT IN THE FAVORABLE RIGHT ENTRANCE
REGION. MEANWHILE...THE SOUTHERN AREA HAS A STRONG LOW TO MID-
LEVEL FRONTOGENESIS FEATURE ALONG THE PRESENT COLD FRONT NEAR
I-70...WHICH FOR ALL INTENSIVE PUPROSES TURNS INTO A STATIONARY
BOUNDARY. SO FOR THE FORECAST...THIS WELL AGREED UPON SPLIT
PRECIPITATION SCENARIO POSES A PROBLEM FROM WHAT WE HAD GOING
PREVIOUSLY. HAVE ADJUSTED PRECIPITATION CHANCES AND QPF QUITE A
BIT LOWER SOUTH OF I-90...SINCE THIS AREA WILL BE ON THE SUBSIDENT
SIDE OF THE F-GEN CIRCULATION. NOTE THAT MODELS LIKE THE 07.00Z
GFS/REGIONAL CANADIAN EVEN SUGGEST THAT SOME LOCATIONS ACROSS
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN COULD END UP DRY.
REGARDING PRECIPITATION TYPE...ALL OF IT SHOULD FALL AS RAIN WITH
WET-BULB ZERO HEIGHTS PROGGED WELL ABOVE 2000 FT. THE PREVIOUS
FORECAST INTRODUCED A CHANCE FOR THUNDER AND THIS STILL LOOKS
REASONABLE AFTER MIDNIGHT...WITH POTENTIAL FOR A FEW HUNDERED J/KG
OF SKINNY CAPE LIFTED FROM 850MB.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN APR 7 2013
OVERALL MUCH OF THE LONG TERM PERIOD LOOKS ACTIVE...THANKS TO THAT
TROUGH DIGGING INTO CALIFORNIA AND NEVADA TONIGHT. QUITE A FEW
DETAILS TO NOTE.
ON MONDAY...THE PAIR OF SHORTWAVES ARE PROGGED TO SHIFT EAST INTO
MICHIGAN DURING THE AFTERNOON...TAKING THE BULK OF THE SPLIT
PRECIPITATION TONIGHT WITH THEM. HOWEVER...THE STORY DOES NOT END
THERE. THE FOCUS TURNS TO THE FRONTAL BOUNDARY NEAR I-70...WHICH BY
ALL MODELS IS SUGGESTED TO LIFT NORTH INTO CENTRAL AND PERHAPS
NORTHERN IA DURING THE AFTERNOON. THE LIFTING NORTH IS A RESULT OF
THE UPPER TROUGHING DEEPENING AND DIGGING INTO THE FOUR CORNERS
REGION...ENHANCING THE WARM ADVECTION DOWNSTREAM. THE 07.00Z
REGIONAL CANADIAN AND NAM SUGGEST THERE IS POTENTIAL FOR SURFACE
BASED CONVECTION TO FIRE ON THIS FRONT. THE 07.00Z GFS...ON THE
OTHER HAND...HAS A FARTHER SOUTH FRONT AND KEEPS THINGS MORE CAPPED.
HOWEVER...ALL THREE MODELS INCLUDING THE 06.12Z ECMWF DEPICT
POTENTIAL FOR FRONTOGENETICALY INDUCED PRECIPITATION NORTH OF THE
FRONTAL BOUNDARY. THUS...A NEED CONTINUES FOR CHANCES OF SHOWERS
ALONG WITH THE THUNDERSTORM MENTION IN THE EVENT THE REGIONAL
CANADIAN/NAM PAN OUT. IF THE REGIONAL CANADIAN/NAM PAN OUT...
CERTAINLY COULD NOT RULE OUT SOME SEVERE POTENTIAL GIVEN 0-6 KM
SHEAR UPWARS OF 45-50 KT. HOWEVER...IT SEEMS LIKE THE BETTER
INSTABILITY IS WEST OF THE FORECAST AREA...THUS KEEPING THE BULK OF
THE SEVERE POTENTIAL TO THE WEST. SPC DAY 2 SEVERE PROBABILITIES
DEPICT THIS AS WELL. DEFINITELY SOMETHING TO KEEP AN EYE
ON....THOUGH. TEMPERATURE FORECAST IS TRICKY AS IT DEPENDS ON THE
FRONTAL POSITION. A NAM/REGIONAL CANADIAN OR EVEN ECMWF SOLUTION
WOULD ALLOW FOR HIGHS IN THE 60S TO POSSIBLY 70 ALONG/SOUTH OF I-90.
THE GFS IS A LITTLE COOLER BUT STILL HAS HIGHS IN THE 60S SOUTH OF
I-90. RAISED HIGHS 5 DEGREES OR SO TO COME BETTER IN AGREEMENT WITH
ALL 07.00Z GUIDANCE...BUT THEY MAY NEED TO BE RAISED MORE...
ESPECIALLY IF MORE SUN OCCURS IN THE AFTERNOON.
THINGS GET MORE INTERESTING HEADING INTO THE MONDAY NIGHT THROUGH
THURSDAY TIME PERIOD. DURING THIS PERIOD...ALL MODELS HAVE THE DEEP
UPPER TROUGH OVER THE FOUR CORNERS SLOWLY LIFTING TO THE
EAST-NORTHEAST. MEANWHILE...AT THE SAME TIME THERE IS A DEEP UPPER
TROUGH HANGING AROUND THE HUDSON BAY INTO NORTHERN ONTARIO AREA...
HELPING TO HOLD AN UPPER JET STREAK IN PLACE OVER THE NORTHERN GREAT
LAKES. THIS MEANS THE FORECAST AREA IS GOING TO BE PLACED IN THE
FAVORABLE RIGHT ENTRANCE REGION UNTIL THE UPPER TROUGH MOVES IN.
MONDAY NIGHT FOR THE MOST PART LOOKS QUIET...WITH ANY SHOWERS AND
POSSIBLE THUNDERSTORMS IN THE EVENING DISSIPATING WITH LOSS OF
DAYTIME HEATING. THE FRONTAL BOUNDARY...IF IT IS NEARBY...LOOKS TO
SLOWLY DROP SOUTH MONDAY NIGHT FORCED BY THAT DEEP UPPER TROUGH TO
OUR NORTH. IT APPEARS THERE MAY BE A MASS OF LOW LEVEL STRATUS THAT
MOVES IN BEHIND THE FRONT...AND WITH LOW LEVEL FRONTOGENESIS BEHIND
THE FRONT WE COULD DEAL WITH SOME LIGHT RAIN OR DRIZZLE.
PRECIPITATION CHANCES DEFINITELY GO ON THE INCREASE FROM SOUTHWEST
TO NORTHEAST THROUGH THE DAY TUESDAY AND INTO TUESDAY NIGHT...IN
RESPONSE TO ISENTROPIC LIFT STRENGTHENING DOWNSTREAM OF THE UPPER
TROUGH PUSHING TO THE EAST-NORTHEAST. SOME CONCERN FOR SOME HEAVIER
RAIN TUESDAY NIGHT...ESPECIALLY ACROSS THE SOUTH...AS PRECIPITABLE
WATER VALUES INCREASE OVER 1 INCH AND SOME WEAK ELEVATED INSTABILITY
MOVES IN FOR THUNDERSTORMS. RAISED BOTH PRECIPITATION CHANCES AND
QPF FOR TUESDAY AND ESPECIALLY TUESDAY NIGHT GIVEN THE STRONG SIGNAL
AMONGST THE 07.00Z ECMWF/GFS/CANADIAN MODELS. FROM WEDNESDAY INTO
THURSDAY...THE CORE OF THE UPPER TROUGH IS PROGGED TO SLOWLY
APPROACH THE FORECAST AREA. AS THIS OCCURS...THE FORECAST AREA
EVENTUALLY ENDS UP ON THE NORTHWEST / COLD SIDE OF A SURFACE LOW
TRACKING TO OUR SOUTH...PLACING THE AREA INTO THE TROWAL AND COLD
CONVEYOR BELT REGION. GIVEN THE GOOD MODEL AGREEMENT AGAIN...RAISED
PRECIPITATION CHANCES UP DURING THIS PERIOD. IN ADDITION...WILL HAVE
TO WATCH FOR SOME SNOW ACCUMULATIONS COME WEDNESDAY NIGHT AND
THURSDAY AS 850MB TEMPS DROP TO -4 TO -8C BY 12Z THURSDAY.
IT SHOULD BE NOTED THAT THE 07.00Z NAM IS AN OUTLIER SOLUTION TO THE
ABOVE SCENARIO...PARTICULARLY FOR TUESDAY THROUGH WEDNESDAY...SINCE
IT EJECTS THE CORE OF THE SOUTHWESTERN TROUGH MUCH QUICKER AND LIFTS
IT FARTHER NORTH. THE NAM WAS DISCOUNTED GIVEN GOOD MODEL AGREEMENT
BETWEEN ALL OTHER MODELS. THE 07.03Z SREF LOOKS LIKE A COMPROMISE
BETWEEN THE NAM AND GFS...BUT THE SREF IS NAM-BIASED DUE TO AN
OVERWHELMING AMOUNT OF NAM MEMBERS. THUS...THE SREF WAS DISCOUNTED
AS WELL.
LOOKING FARTHER AHEAD...GOOD MODEL AGREEMENT EXISTS AMONGST THE
07.00Z ECMWF/GFS/CANADIAN ON BRINGING COLD CANADIAN HIGH PRESSURE
INTO THE AREA THURSDAY NIGHT THROUGH FRIDAY NIGHT. THIS SHOULD HELP
DRY THINGS OUT. LEFT A CONSENUS 20 PERCENT CHANCE OF PRECIPITATION
IN THURSDAY NIGHT...BUT THIS PERIOD MAY EVENTUALLY END UP DRY. WILL
NEED TO WATCH SOME OF THE LOW TEMPERATURES TOO FOR BOTH THURSDAY
NIGHT AND FRIDAY NIGHT...DEPENDING ON HOW MUCH FRESH SNOW WE PICK UP
AND FOR FRIDAY NIGHT HOW MUCH IS STILL ON THE GROUND. A WARM
ADVECTION PATTERN SETS UP FOR SATURDAY AHEAD OF NEW TROUGHING
DROPPING INTO THE NORTHERN ROCKIES. FOLLOWED THE CONSENSUS HERE OF
BRINGING SOME 20-30 PERCENT CHANCES OF PRECIPITATION ACROSS THE AREA
ON SATURDAY. NEED TO MAINTAIN A RAIN/SNOW MIX BECAUSE 850MB TEMPS
ARE STILL SLOW TO WARM...ESPECIALLY IN THE ECMWF WHERE IT KEEPS THEM
BELOW 0C THROUGH 00Z SUNDAY.
&&
.AVIATION...TODAY AND TONIGHT
638 AM CDT SUN APR 7 2013
BUFKIT SOUNDINGS SUGGEST THAT THE MVRF CLOUDS WILL LINGER THROUGH
THIS MORNING...AND THEN QUICKLY DISSIPATE BETWEEN 07.18Z AND
07.21Z. A 5 TO 10K CLOUD DECK WILL MOVE BACK INTO THE AREA BETWEEN
07.23Z AND 08.03Z AND THEN PERSIST THROUGH THE REMAINDER OF THE
NIGHT AS A LOW PRESSURE SYSTEM PASSES TO THE NORTHWEST OF THE TAF
SITES. SCATTERED SHOWERS WILL MOVE INTO THE AREA AFTER
08.06Z...BUT SHOULD NOT AFFECT THE VISIBILITIES TOO MUCH.
&&
.HYDROLOGY...
ISSUED AT 342 AM CDT SUN APR 7 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH MONDAY MORNING.
MEANWHILE ON THE BLACK...ANOTHER BRIEF ICE JAM LOOKS LIKE IT MAY
HAVE FORMED AROUND NEILLSVILLE...WITH A SPIKE UP OF 4 FEET BUT STILL
WELL WITHIN THE RIVER BANK. DOWNSTREAM...SO FAR THE BLACK REMAINS
WITHIN THE RIVER BANK.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTHEAST OF THE INTERSTATE 94 CORRIDOR WITH 2 TO 7 INCHES OF
SNOW DEPTH IN PLACES. THE DEEPEST SNOW PACK IS OVER THE NORTHERN
MOST PARTS OF TAYLOR WHERE AROUND A FOOT OF SNOW REMAINS ON THE
GROUND. SNOW WATER EQUIVALENT OF 1 TO 2 INCHES IS MAINLY NORTH OF
THE INTERSTATE 94 CORRIDOR WITH THE GREATEST SNOW WATER EQUIVALENT
OF 2 TO 4 INCHES IN NORTHERN TAYLOR COUNTY.
RAINFALL...
LESS RAINFALL IS ANTICIPATED TONIGHT INTO MONDAY THAN PREVIOUSLY
EXPECTED...WITH UPWARDS OF 1/4 TO 1/2 INCH NORTH OF I-90 AND LESS
THAN A 1/4 INCH TO THE SOUTH. WILL STILL NEED TO WATCH TUESDAY
THROUGH WEDNESDAY...THOUGH. BY WEDNESDAY MORNING...CURRENTLY
ANTICIPATING AMOUNTS BETWEEN 3/4 INCH AND 1.25 INCHES SOUTH OF
HIGHWAY 10 TO LESS THAN A 1/2 INCH TO THE NORTH. IF THE SYSTEM
BRINGING THIS RAIN SHIFTS FARTHER NORTH...THE HEAVY RAIN AREA WILL
SHIFT NORTH AS WELL...PLACING IT WHERE RAIN IS NOT NEEDED.
TEMPERATURES...
HIGHS TODAY ARE GOING TO BE COOLER...IN THE THE MIDDLE 40S/AROUND 50
NORTH OF I-94 AND IN THE 50S SOUTH OF THERE. WARMER CONDITIONS LOOK
ON TAP FOR MONDAY...WITH MOSTLY 50S NORTH OF I-94 AND 60S SOUTH.
TEMPERATURES THEN COOL INTO THE 40S FOR TUESDAY AND WEDNESDAY AND
POSSIBLY STRUGGLE TO GET TO 40 BY THURSDAY. THE TEMPERATURE MAY NOT
MATTER IN A FEW DAYS AS MOST OF THE SNOW PACK MAY BE GONE...UNTIL
POTENTIALL A SMALL SNOW PACK RE-ESTABLISHES ITSELF THURSDAY MORNING.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING REMAINS ALONG THE TREMPEALEAU AND BLACK
RIVERS AS SNOW MELT CONTINUES...ALONG WITH THE PERIODS OF RAINFALL
TONIGHT INTO MONDAY AS WELL AS TUESDAY THROUGH WEDNESDAY. HAVE A
HYDROLOGIC OUTLOOK PRODUCT OUT TO HEIGHTEN THIS AWARENESS. ALTHOUGH
THE TUESDAY INTO WEDNESDAY MODERATE TO HEAVY RAIN IS FORECAST MAINLY
SOUTH OF I-90...CURRENTLY THINKING THAT THE RIVERS SHOULD BE ABLE TO
ABSORB IT. A QUICK MODEL OF THE TURKEY RIVER AT GARBER USING THE
FORECAST QPF WOULD BRING THE RIVER ABOVE ACTION STAGE BUT NOT TO
FLOOD. THUS...DID NOT EXPAND THE HYDROLOGIC OUTLOOK SOUTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 AM CDT SUN APR 7 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SUN APR 7 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED UPPER TROUGHING APPROACHING THE PACIFIC
NORTHWEST...WEAK RIDGING OVER THE NORTHERN U.S. ROCKIES INTO THE
DAKOTAS...AND A SHORTWAVE TROUGH OVER EASTERN WISCONSIN. ALSO OF
NOTE ON WATER VAPOR WERE A PAIR OF SHORTWAVES MOVING THROUGH THE
WEAK RIDGING...ONE IN SOUTH CENTRAL WYOMING AND THE OTHER IN
NORTHWEST COLORADO. THE FORECAST AREA LIES IN SUBSIDENCE IN THE
WAKE OF THE EASTERN WISCONSIN SHORTWAVE TROUGH...SEEN AS AN
INVERSION BETWEEN 775 AND 850MB ON THE 00Z MPX SOUNDING. THIS
INVERSION WAS ALSO SATURATED... REFLECTED TOO BY PLENTY OF STRATUS
CLOUDS ON 11-3.9UM IMAGERY FROM THE EASTERN DAKOTAS INTO THE
FORECAST AREA. COOLER AIR HAS BEEN FILTERING IN BEHIND THE
SHORTWAVE AS WELL WITH 850MB TEMPS NOW DOWN TO +2 TO -3C ACROSS
THE FORECAST AREA PER RAP ANALYSIS...COLDEST OVER CENTRAL
WISCONSIN. AT THE SURFACE...HIGH PRESSURE WAS SEEN DROPPING SOUTH
INTO WESTERN MINNESOTA...IN THE WAKE OF LOW PRESSURE OVER NORTHERN
LAKE MICHIGAN AND ITS COLD FRONT WHICH EXTENDS SOUTHWEST TO KANSAS
CITY.
A PATTERN CHANGE IS FORECAST TO OCCUR ALOFT DURING THE NEXT 24 HOURS
AS THE UPPER TROUGH SEEN OFF THE PACIFIC NORTHWEST SHARPLY DIGS
SOUTH INTO CALIFORNIA AND NEVADA. IN RESPONSE...RIDGING WILL BUILD
DOWNSTREAM...ADJUSTING THE UPPER LEVEL FLOW TO SOUTHWESTERLY OVER
THE FORECAST AREA. THIS MEANS THAT THE RECENT LOW LEVEL COLD
ADVECTION WILL COME TO AN END SHORTLY...WITH WARM ADVECTION PROGGED
TO BEGIN BETWEEN 12-18Z TODAY AND CONTINUE THROUGH TONIGHT. IN
ADDITION...MODELS HAVE BEEN CONSISTENT IN SHOWING THE PAIR OF
SHORTWAVES SEEN IN WYOMING AND COLORADO TO AFFECT THE FORECAST AREA
LATE TONIGHT AS THEY RIDE THROUGH THE SOUTHWEST FLOW.
THE FIRST TWO ISSUES FOR THE SHORT TERM PERIOD ARE THE CLOUDS AND
HIGH TEMPERATURES TODAY. THE PRESENT STRATUS DECK DOES HAVE SOME
HOLES IN IT ON ITS SOUTHERN SIDE. THESE HOLES SHOULD EXPAND THROUGH
THE MORNING AS DIURNAL MIXING COMMENCES. 07.00Z NAM LOW LEVEL RH
FIELDS...WHICH GENERALLY TEND PESSIMISTIC...ALSO SUGGEST THAT THE
STRATUS DECK WILL MOSTLY MIX OUT BY 18Z SOUTH OF US HIGHWAY 10.
LATER IN THE AFTERNOON...SAY 21Z AND AFTER...MID AND HIGH CLOUDS
CURRENTLY SPREADING INTO THE PLAINS STATES ARE PROGGED TO MOVE INTO
THE FORECAST AREA. THUS WE SHOULD SEE AT LEAST A FEW HOURS OF MOSTLY
SUNNY SKIES TODAY. WITH 850MB TEMPS CLIMBING TO 0C NORTH AND 6C
SOUTH BY 18Z...ANTICIPATING THAT MOST LOCATIONS MINUS NORTH OF
HIGHWAY 10 WHERE MORE CLOUDS AND SNOW EXIST WILL CLIMB INTO THE 50S.
WARMEST TEMPERATURES...APPROACHING 60...ARE EXPECTED IN THE FAR
SOUTH.
THE NEXT ISSUE FOR THE SHORT TERM PERIOD IS THE POTENTIAL FOR
PRECIPITATION VERY LATE THIS AFTERNOON INTO TONIGHT...DUE TO THE
WARM ADVECTION PATTERN AND THE APPROACH OF THE PAIR OF SHORTWAVES.
THE 07.00Z GFS/06.12Z ECMWF ALREADY SHOW HINTS OF WARM ADVECTION /
ISENTROPICALLY INDUCED PRECIPITATION AFFECTING FAR WESTERN PORTIONS
OF THE FORECAST AREA BETWEEN 21-00Z TODAY. THINKING THIS MIGHT BE A
BIT FAST...WITH THE 07.00Z NAM/REGIONAL CANADIAN/HIRES-ARW AND
07.03Z SREF ALL SLOWER. THUS...PLAN ON KEEPING CONDITIONS DRY TIL
00Z. AS WE HEAD THROUGH TONIGHT...THERE IS A STRONG CONSENSUS
AMONGST ALL MODEL GUIDANCE OF A PRECIPITATION SPLIT. THE NORTHERN
AREA TRACKS FROM NORTHWEST IA/SOUTHERN MN INTO NORTHWEST
WISCONSIN. THE SOUTHERN AREA TRACKS FROM NORTHERN MISSOURI INTO
SOUTHEAST IA AND NORTHWEST IL. THIS SPLIT APPEARS TO BE A RESULT
OF HOW THE PAIR OF SHORTWAVES APPROACHING THE FORECAST AREA LATE
TONIGHT INTERACT WITH THE ISENTROPIC LIFT PATTERN IN PLACE. 850MB
MOISTURE TRANSPORT FIELDS SHOW THE SPLIT INTERACTION WITH THE
ISENTROPIC LIFT PATTERN NICELY. IN ADDITION...THERE ARE OTHER
SUPPORTING FEATURES. FOR EXAMPLE...THE NORTHERN AREA BECOMES
INFLUENECED BY A DEVELOPING AND STRENGTHENING UPPER JET STREAK
OVER UPPER MICHIGAN...PLACING IT IN THE FAVORABLE RIGHT ENTRANCE
REGION. MEANWHILE...THE SOUTHERN AREA HAS A STRONG LOW TO MID-
LEVEL FRONTOGENESIS FEATURE ALONG THE PRESENT COLD FRONT NEAR
I-70...WHICH FOR ALL INTENSIVE PUPROSES TURNS INTO A STATIONARY
BOUNDARY. SO FOR THE FORECAST...THIS WELL AGREED UPON SPLIT
PRECIPITATION SCENARIO POSES A PROBLEM FROM WHAT WE HAD GOING
PREVIOUSLY. HAVE ADJUSTED PRECIPITATION CHANCES AND QPF QUITE A
BIT LOWER SOUTH OF I-90...SINCE THIS AREA WILL BE ON THE SUBSIDENT
SIDE OF THE F-GEN CIRCULATION. NOTE THAT MODELS LIKE THE 07.00Z
GFS/REGIONAL CANADIAN EVEN SUGGEST THAT SOME LOCATIONS ACROSS
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN COULD END UP DRY.
REGARDING PRECIPITATION TYPE...ALL OF IT SHOULD FALL AS RAIN WITH
WET-BULB ZERO HEIGHTS PROGGED WELL ABOVE 2000 FT. THE PREVIOUS
FORECAST INTRODUCED A CHANCE FOR THUNDER AND THIS STILL LOOKS
REASONABLE AFTER MIDNIGHT...WITH POTENTIAL FOR A FEW HUNDERED J/KG
OF SKINNY CAPE LIFTED FROM 850MB.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 342 AM CDT SUN APR 7 2013
OVERALL MUCH OF THE LONG TERM PERIOD LOOKS ACTIVE...THANKS TO THAT
TROUGH DIGGING INTO CALIFORNIA AND NEVADA TONIGHT. QUITE A FEW
DETAILS TO NOTE.
ON MONDAY...THE PAIR OF SHORTWAVES ARE PROGGED TO SHIFT EAST INTO
MICHIGAN DURING THE AFTERNOON...TAKING THE BULK OF THE SPLIT
PRECIPITATION TONIGHT WITH THEM. HOWEVER...THE STORY DOES NOT END
THERE. THE FOCUS TURNS TO THE FRONTAL BOUNDARY NEAR I-70...WHICH BY
ALL MODELS IS SUGGESTED TO LIFT NORTH INTO CENTRAL AND PERHAPS
NORTHERN IA DURING THE AFTERNOON. THE LIFTING NORTH IS A RESULT OF
THE UPPER TROUGHING DEEPENING AND DIGGING INTO THE FOUR CORNERS
REGION...ENHANCING THE WARM ADVECTION DOWNSTREAM. THE 07.00Z
REGIONAL CANADIAN AND NAM SUGGEST THERE IS POTENTIAL FOR SURFACE
BASED CONVECTION TO FIRE ON THIS FRONT. THE 07.00Z GFS...ON THE
OTHER HAND...HAS A FARTHER SOUTH FRONT AND KEEPS THINGS MORE CAPPED.
HOWEVER...ALL THREE MODELS INCLUDING THE 06.12Z ECMWF DEPICT
POTENTIAL FOR FRONTOGENETICALY INDUCED PRECIPITATION NORTH OF THE
FRONTAL BOUNDARY. THUS...A NEED CONTINUES FOR CHANCES OF SHOWERS
ALONG WITH THE THUNDERSTORM MENTION IN THE EVENT THE REGIONAL
CANADIAN/NAM PAN OUT. IF THE REGIONAL CANADIAN/NAM PAN OUT...
CERTAINLY COULD NOT RULE OUT SOME SEVERE POTENTIAL GIVEN 0-6 KM
SHEAR UPWARS OF 45-50 KT. HOWEVER...IT SEEMS LIKE THE BETTER
INSTABILITY IS WEST OF THE FORECAST AREA...THUS KEEPING THE BULK OF
THE SEVERE POTENTIAL TO THE WEST. SPC DAY 2 SEVERE PROBABILITIES
DEPICT THIS AS WELL. DEFINITELY SOMETHING TO KEEP AN EYE
ON....THOUGH. TEMPERATURE FORECAST IS TRICKY AS IT DEPENDS ON THE
FRONTAL POSITION. A NAM/REGIONAL CANADIAN OR EVEN ECMWF SOLUTION
WOULD ALLOW FOR HIGHS IN THE 60S TO POSSIBLY 70 ALONG/SOUTH OF I-90.
THE GFS IS A LITTLE COOLER BUT STILL HAS HIGHS IN THE 60S SOUTH OF
I-90. RAISED HIGHS 5 DEGREES OR SO TO COME BETTER IN AGREEMENT WITH
ALL 07.00Z GUIDANCE...BUT THEY MAY NEED TO BE RAISED MORE...
ESPECIALLY IF MORE SUN OCCURS IN THE AFTERNOON.
THINGS GET MORE INTERESTING HEADING INTO THE MONDAY NIGHT THROUGH
THURSDAY TIME PERIOD. DURING THIS PERIOD...ALL MODELS HAVE THE DEEP
UPPER TROUGH OVER THE FOUR CORNERS SLOWLY LIFTING TO THE
EAST-NORTHEAST. MEANWHILE...AT THE SAME TIME THERE IS A DEEP UPPER
TROUGH HANGING AROUND THE HUDSON BAY INTO NORTHERN ONTARIO AREA...
HELPING TO HOLD AN UPPER JET STREAK IN PLACE OVER THE NORTHERN GREAT
LAKES. THIS MEANS THE FORECAST AREA IS GOING TO BE PLACED IN THE
FAVORABLE RIGHT ENTRANCE REGION UNTIL THE UPPER TROUGH MOVES IN.
MONDAY NIGHT FOR THE MOST PART LOOKS QUIET...WITH ANY SHOWERS AND
POSSIBLE THUNDERSTORMS IN THE EVENING DISSIPATING WITH LOSS OF
DAYTIME HEATING. THE FRONTAL BOUNDARY...IF IT IS NEARBY...LOOKS TO
SLOWLY DROP SOUTH MONDAY NIGHT FORCED BY THAT DEEP UPPER TROUGH TO
OUR NORTH. IT APPEARS THERE MAY BE A MASS OF LOW LEVEL STRATUS THAT
MOVES IN BEHIND THE FRONT...AND WITH LOW LEVEL FRONTOGENESIS BEHIND
THE FRONT WE COULD DEAL WITH SOME LIGHT RAIN OR DRIZZLE.
PRECIPITATION CHANCES DEFINITELY GO ON THE INCREASE FROM SOUTHWEST
TO NORTHEAST THROUGH THE DAY TUESDAY AND INTO TUESDAY NIGHT...IN
RESPONSE TO ISENTROPIC LIFT STRENGTHENING DOWNSTREAM OF THE UPPER
TROUGH PUSHING TO THE EAST-NORTHEAST. SOME CONCERN FOR SOME HEAVIER
RAIN TUESDAY NIGHT...ESPECIALLY ACROSS THE SOUTH...AS PRECIPITABLE
WATER VALUES INCREASE OVER 1 INCH AND SOME WEAK ELEVATED INSTABILITY
MOVES IN FOR THUNDERSTORMS. RAISED BOTH PRECIPITATION CHANCES AND
QPF FOR TUESDAY AND ESPECIALLY TUESDAY NIGHT GIVEN THE STRONG SIGNAL
AMONGST THE 07.00Z ECMWF/GFS/CANADIAN MODELS. FROM WEDNESDAY INTO
THURSDAY...THE CORE OF THE UPPER TROUGH IS PROGGED TO SLOWLY
APPROACH THE FORECAST AREA. AS THIS OCCURS...THE FORECAST AREA
EVENTUALLY ENDS UP ON THE NORTHWEST / COLD SIDE OF A SURFACE LOW
TRACKING TO OUR SOUTH...PLACING THE AREA INTO THE TROWAL AND COLD
CONVEYOR BELT REGION. GIVEN THE GOOD MODEL AGREEMENT AGAIN...RAISED
PRECIPITATION CHANCES UP DURING THIS PERIOD. IN ADDITION...WILL HAVE
TO WATCH FOR SOME SNOW ACCUMULATIONS COME WEDNESDAY NIGHT AND
THURSDAY AS 850MB TEMPS DROP TO -4 TO -8C BY 12Z THURSDAY.
IT SHOULD BE NOTED THAT THE 07.00Z NAM IS AN OUTLIER SOLUTION TO THE
ABOVE SCENARIO...PARTICULARLY FOR TUESDAY THROUGH WEDNESDAY...SINCE
IT EJECTS THE CORE OF THE SOUTHWESTERN TROUGH MUCH QUICKER AND LIFTS
IT FARTHER NORTH. THE NAM WAS DISCOUNTED GIVEN GOOD MODEL AGREEMENT
BETWEEN ALL OTHER MODELS. THE 07.03Z SREF LOOKS LIKE A COMPROMISE
BETWEEN THE NAM AND GFS...BUT THE SREF IS NAM-BIASED DUE TO AN
OVERWHELMING AMOUNT OF NAM MEMBERS. THUS...THE SREF WAS DISCOUNTED
AS WELL.
LOOKING FARTHER AHEAD...GOOD MODEL AGREEMENT EXISTS AMONGST THE
07.00Z ECMWF/GFS/CANADIAN ON BRINGING COLD CANADIAN HIGH PRESSURE
INTO THE AREA THURSDAY NIGHT THROUGH FRIDAY NIGHT. THIS SHOULD HELP
DRY THINGS OUT. LEFT A CONSENUS 20 PERCENT CHANCE OF PRECIPITATION
IN THURSDAY NIGHT...BUT THIS PERIOD MAY EVENTUALLY END UP DRY. WILL
NEED TO WATCH SOME OF THE LOW TEMPERATURES TOO FOR BOTH THURSDAY
NIGHT AND FRIDAY NIGHT...DEPENDING ON HOW MUCH FRESH SNOW WE PICK UP
AND FOR FRIDAY NIGHT HOW MUCH IS STILL ON THE GROUND. A WARM
ADVECTION PATTERN SETS UP FOR SATURDAY AHEAD OF NEW TROUGHING
DROPPING INTO THE NORTHERN ROCKIES. FOLLOWED THE CONSENSUS HERE OF
BRINGING SOME 20-30 PERCENT CHANCES OF PRECIPITATION ACROSS THE AREA
ON SATURDAY. NEED TO MAINTAIN A RAIN/SNOW MIX BECAUSE 850MB TEMPS
ARE STILL SLOW TO WARM...ESPECIALLY IN THE ECMWF WHERE IT KEEPS THEM
BELOW 0C THROUGH 00Z SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1015 PM CDT SAT APR 6 2013
THERE WILL BE A DECREASE IN THE WINDS OVERNIGHT AS THE PRESSURE
GRADIENT SLACKENS. MVFR CIGS FROM 1500-2500 WILL CONTINUE...BUT SEE
SOME THREAT FOR SUB 1 KFT CIGS AT KRST. NOT CONFIDENT ENOUGH TO ADD
TO THE FORECAST...BUT TRENDS WILL BE WATCHED CLOSELY. THE LOW CIGS
WILL HANG INTO SUNDAY MORNING. BUFKIT SOUNDINGS VIA THE
RAP13/NAM/GFS ALL SUGGEST SOME MIXING BY 18Z...WHICH WOULD HELP
BREAK UP THE CLOUDS...INCREASING THE CHANCES FOR SCT CONDITIONS FOR
THE AFTERNOON. WILL STAY WITH THIS TREND.
MORE UPPER LEVEL ENERGY WILL SPIN ACROSS THE REGION SUNDAY
NIGHT/MON. CLOUDS WILL QUICKLY RETURN SUNDAY EVENING AS A
RESULT...WITH RAIN CHANCES MOVING IN BETWEEN 06-12Z MONDAY. THERE
MIGHT BE ENOUGH INSTABILITY/FORCING FOR AN ISOLATED
THUNDERSTORM...BUT NOT ENOUGH OF A CHANCE TO INCLUDE IN THE
FORECAST. IT SHOULD BE NOTED THAT THE NAM/GFS/ECMWF ALL SUGGEST THAT
THERE COULD BE TWO MAIN REGIONS FOR PCPN...WHICH WOULD GO NORTH AND
SOUTH OF THE TAF SITES. STILL WOULD BE ENOUGH FORCING FOR SOME -SHRA
CHANCES...BUT ACCUMS AND IMPACTS TO VSBYS WOULD BE MUCH LESS.
&&
.HYDROLOGY...
ISSUED AT 342 AM CDT SUN APR 7 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH MONDAY MORNING.
MEANWHILE ON THE BLACK...ANOTHER BRIEF ICE JAM LOOKS LIKE IT MAY
HAVE FORMED AROUND NEILLSVILLE...WITH A SPIKE UP OF 4 FEET BUT STILL
WELL WITHIN THE RIVER BANK. DOWNSTREAM...SO FAR THE BLACK REMAINS
WITHIN THE RIVER BANK.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTHEAST OF THE INTERSTATE 94 CORRIDOR WITH 2 TO 7 INCHES OF
SNOW DEPTH IN PLACES. THE DEEPEST SNOW PACK IS OVER THE NORTHERN
MOST PARTS OF TAYLOR WHERE AROUND A FOOT OF SNOW REMAINS ON THE
GROUND. SNOW WATER EQUIVALENT OF 1 TO 2 INCHES IS MAINLY NORTH OF
THE INTERSTATE 94 CORRIDOR WITH THE GREATEST SNOW WATER EQUIVALENT
OF 2 TO 4 INCHES IN NORTHERN TAYLOR COUNTY.
RAINFALL...
LESS RAINFALL IS ANTICIPATED TONIGHT INTO MONDAY THAN PREVIOUSLY
EXPECTED...WITH UPWARDS OF 1/4 TO 1/2 INCH NORTH OF I-90 AND LESS
THAN A 1/4 INCH TO THE SOUTH. WILL STILL NEED TO WATCH TUESDAY
THROUGH WEDNESDAY...THOUGH. BY WEDNESDAY MORNING...CURRENTLY
ANTICIPATING AMOUNTS BETWEEN 3/4 INCH AND 1.25 INCHES SOUTH OF
HIGHWAY 10 TO LESS THAN A 1/2 INCH TO THE NORTH. IF THE SYSTEM
BRINGING THIS RAIN SHIFTS FARTHER NORTH...THE HEAVY RAIN AREA WILL
SHIFT NORTH AS WELL...PLACING IT WHERE RAIN IS NOT NEEDED.
TEMPERATURES...
HIGHS TODAY ARE GOING TO BE COOLER...IN THE THE MIDDLE 40S/AROUND 50
NORTH OF I-94 AND IN THE 50S SOUTH OF THERE. WARMER CONDITIONS LOOK
ON TAP FOR MONDAY...WITH MOSTLY 50S NORTH OF I-94 AND 60S SOUTH.
TEMPERATURES THEN COOL INTO THE 40S FOR TUESDAY AND WEDNESDAY AND
POSSIBLY STRUGGLE TO GET TO 40 BY THURSDAY. THE TEMPERATURE MAY NOT
MATTER IN A FEW DAYS AS MOST OF THE SNOW PACK MAY BE GONE...UNTIL
POTENTIALL A SMALL SNOW PACK RE-ESTABLISHES ITSELF THURSDAY MORNING.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
MAIN CONCERN FOR FLOODING REMAINS ALONG THE TREMPEALEAU AND BLACK
RIVERS AS SNOW MELT CONTINUES...ALONG WITH THE PERIODS OF RAINFALL
TONIGHT INTO MONDAY AS WELL AS TUESDAY THROUGH WEDNESDAY. HAVE A
HYDROLOGIC OUTLOOK PRODUCT OUT TO HEIGHTEN THIS AWARENESS. ALTHOUGH
THE TUESDAY INTO WEDNESDAY MODERATE TO HEAVY RAIN IS FORECAST MAINLY
SOUTH OF I-90...CURRENTLY THINKING THAT THE RIVERS SHOULD BE ABLE TO
ABSORB IT. A QUICK MODEL OF THE TURKEY RIVER AT GARBER USING THE
FORECAST QPF WOULD BRING THE RIVER ABOVE ACTION STAGE BUT NOT TO
FLOOD. THUS...DID NOT EXPAND THE HYDROLOGIC OUTLOOK SOUTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS MIAMI FL
402 AM EDT TUE APR 9 2013
.DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
&&
.MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
&&
.FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/GREGORIA
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
234 AM CDT TUE APR 9 2013
...UPDATED TO SHORT TERM, WITH WIND ADVISORY INFO BELOW...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM CDT MON APR 8 2013
A CHALLENGING FORECAST IS IN STORE FOR TUESDAY NIGHT WITH RESPECT TO
PRECIPITATION CHANCES AND PRECIPITATION TYPE. WINDY CONDITIONS
USHER IN MUCH COLDER AIR FOR WEDNESDAY MORNING, FOLLOWED BY A
GRADUAL WARMUP TOWARD THE WEEKEND WITH MINOR OPPORTUNITIES FOR LIGHT
PRECIPITATION.
THE INITIAL FORECAST CHALLENGE REVOLVES AROUND CHANCES FOR
PRECIPITATION TUESDAY EVENING. THE MODELS ARE IN GENERALLY GOOD
CONSENSUS IN EJECTING THE 700 MB LOW ACROSS SOUTHWEST NEBRASKA,
PLACING THE BEST SIGNAL FOR MOIST CONVEYOR BELT PRECIPITATION ACROSS
SOUTH CENTRAL AND CENTRAL KANSAS. POTENTIAL FOR A SIGNIFICANT
PORTION OF SOUTHWEST KANSAS TO BE IN THE DRY SLOT REGION EXISTS.
WITH THESE FACTORS IN MIND, THE LOWEST CHANCES FOR ACCUMULATING
PRECIPITATION ARE IN THE FAR WEST WITH BETTER CHANCES ACROSS THE
CENTRAL REGION. THE THERMODYNAMIC PROFILES FROM A TOP DOWN
PERSPECTIVE ALSO SUGGEST A CHANCE FOR FREEZING RAIN OR EVEN ICE
PELLETS (SLEET) IN A NARROW TIME WINDOW AFTER THE INTENSE LOW LEVEL
WARM ADVECTION OCCURS ACROSS THE AREA. GROUND TEMPERATURES ARE WARM
ENOUGH AT THIS TIME OF YEAR (MID 50`S IN THE MORNING) THAT FREEZING
RAIN ON THE GROUND WILL NOT BE AN ISSUE, BUT RATHER FREEZING OF
ELEVATED SURFACES. THE DEEPER COLD AIR MAY QUICKLY CAUSE POTENTIAL
FOR SNOW WITH LIGHT ACCUMULATIONS THROUGH THE OVERNIGHT IF DRY
SLOTTING DOES NOT OCCUR.
WEDNESDAY MORNING SHOULD BE COLD WITH TEMPERATURES AS LOW AS THE
TEENS AND 20`S. ALTHOUGH MUCH BELOW NORMAL, IT IS NOT COMPLETELY
UNCOMMON, AS THE CLIMATOLOGICAL LAST FREEZE FOR SOUTHWEST AND SOUTH
CENTRAL KANSAS IS GENERALLY CENTERED AROUND 10 DAYS FROM NOW.
THE REMAINDER OF THE WEEK WILL BRING A SLOW MODERATION OF
TEMPERATURES TOWARD NORMAL AS BROAD CYCLONIC UPPER FLOW DOMINATES
THE UPPER FLOW. MODELS INDICATE ADDITIONAL EMBEDDED WAVES INTO
THE ROCKIES REGION WHICH PRODUCE RAIN/SNOW EPISODES ACROSS THE FAR
CENTRAL HIGH PLAINS CENTERED AROUND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 19 37 24 / 30 30 10 10
GCK 51 17 35 23 / 30 30 10 10
EHA 46 17 38 24 / 20 20 0 0
LBL 53 18 37 24 / 20 20 10 0
HYS 60 19 37 27 / 40 50 10 10
P28 74 25 44 29 / 40 50 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM CDT /6 AM MDT/ THIS MORNING TO 10 PM CDT
/9 PM MDT/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>080-
084>089.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
207 AM CDT TUE APR 9 2013
...UPDATE FOR THE SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 203 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM CDT MON APR 8 2013
A CHALLENGING FORECAST IS IN STORE FOR TUESDAY NIGHT WITH RESPECT TO
PRECIPITATION CHANCES AND PRECIPITATION TYPE. WINDY CONDITIONS
USHER IN MUCH COLDER AIR FOR WEDNESDAY MORNING, FOLLOWED BY A
GRADUAL WARMUP TOWARD THE WEEKEND WITH MINOR OPPORTUNITIES FOR LIGHT
PRECIPITATION.
THE INITIAL FORECAST CHALLENGE REVOLVES AROUND CHANCES FOR
PRECIPITATION TUESDAY EVENING. THE MODELS ARE IN GENERALLY GOOD
CONSENSUS IN EJECTING THE 700 MB LOW ACROSS SOUTHWEST NEBRASKA,
PLACING THE BEST SIGNAL FOR MOIST CONVEYOR BELT PRECIPITATION ACROSS
SOUTH CENTRAL AND CENTRAL KANSAS. POTENTIAL FOR A SIGNIFICANT
PORTION OF SOUTHWEST KANSAS TO BE IN THE DRY SLOT REGION EXISTS.
WITH THESE FACTORS IN MIND, THE LOWEST CHANCES FOR ACCUMULATING
PRECIPITATION ARE IN THE FAR WEST WITH BETTER CHANCES ACROSS THE
CENTRAL REGION. THE THERMODYNAMIC PROFILES FROM A TOP DOWN
PERSPECTIVE ALSO SUGGEST A CHANCE FOR FREEZING RAIN OR EVEN ICE
PELLETS (SLEET) IN A NARROW TIME WINDOW AFTER THE INTENSE LOW LEVEL
WARM ADVECTION OCCURS ACROSS THE AREA. GROUND TEMPERATURES ARE WARM
ENOUGH AT THIS TIME OF YEAR (MID 50`S IN THE MORNING) THAT FREEZING
RAIN ON THE GROUND WILL NOT BE AN ISSUE, BUT RATHER FREEZING OF
ELEVATED SURFACES. THE DEEPER COLD AIR MAY QUICKLY CAUSE POTENTIAL
FOR SNOW WITH LIGHT ACCUMULATIONS THROUGH THE OVERNIGHT IF DRY
SLOTTING DOES NOT OCCUR.
WEDNESDAY MORNING SHOULD BE COLD WITH TEMPERATURES AS LOW AS THE
TEENS AND 20`S. ALTHOUGH MUCH BELOW NORMAL, IT IS NOT COMPLETELY
UNCOMMON, AS THE CLIMATOLOGICAL LAST FREEZE FOR SOUTHWEST AND SOUTH
CENTRAL KANSAS IS GENERALLY CENTERED AROUND 10 DAYS FROM NOW.
THE REMAINDER OF THE WEEK WILL BRING A SLOW MODERATION OF
TEMPERATURES TOWARD NORMAL AS BROAD CYCLONIC UPPER FLOW DOMINATES
THE UPPER FLOW. MODELS INDICATE ADDITIONAL EMBEDDED WAVES INTO
THE ROCKIES REGION WHICH PRODUCE RAIN/SNOW EPISODES ACROSS THE FAR
CENTRAL HIGH PLAINS CENTERED AROUND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 19 37 24 / 20 30 10 10
GCK 51 17 35 23 / 30 30 10 10
EHA 46 17 38 24 / 20 20 0 0
LBL 53 18 37 24 / 20 20 10 0
HYS 60 19 37 27 / 40 50 10 10
P28 74 25 44 29 / 40 50 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1212 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1008 PM CDT MON APR 8 2013
MOST OF THE PRECIPITATION THIS EVENING HAS BEEN FOCUSED ACROSS FAR
NORTHWEST KANSAS AND SOUTHWEST AND CENTRAL NEBRASKA WHERE A FRONT
STRETCHES OVER THE AREA. LATEST TOP SOUNDING CONTINUED TO SHOW A
DECENT CAPPING INVERSION IN PLACE NEAR 700 MB...WITH MODEL SOUNDINGS
SHOWING LITTLE CHANGE THROUGH THE OVERNIGHT PERIOD. AS A
RESULT...HAVE CONTINUED TO TREND DOWN POPS ACROSS MUCH OF THE
CWA...ESPECIALLY OVER EAST CENTRAL KANSAS. WITH THE LLJ INCREASING
OVER NORTH CENTRAL AND NORTHEAST KANSAS TONIGHT...STILL CANNOT RULE
OUT SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING THIS
EVENING NEAR THE NEBRASKA/KANSAS BORDER...SO HAVE KEPT CHANCE POPS
IN FOR THAT AREA THROUGH THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
19Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW DIGGING SOUTHEAST INTO
SOUTHERN NV AND AZ. AT THE SURFACE A WEAK BOUNDARY NOTED MORE IN THE
DEWPOINT FIELD HAS LIFTED INTO SOUTHERN NEB.
TONIGHT WITH THE UPPER LOW ACROSS THE SOUTHWEST...THE FORECAST AREA
SHOULD REMAIN MAINLY UNDER SHORTWAVE RIDGING ALOFT WITH SOUTHERLY
RETURN FLOW PERSISTING. THIS LOW LEVEL FLOW IS EXPECTED TO ADVECT AN
ELEVATED MIXED LAYER OR CAPPING INVERSION NORTH INTO NEB AND THE
LATEST RAP SOUNDINGS SUPPORT THIS IDEA WITH A STRENGTHENING
INVERSION EARLY THIS EVENING ALONG THE NEB STATE LINE. SO AM
THINKING THAT ELEVATED STORMS ARE MORE LIKELY TO OCCUR OVER SOUTHERN
NEB WHERE ISENTROPIC UPGLIDE INTERACTS WITH THE WEAK BOUNDARY. SOME
OF THE LATEST HI RES MODELS ARE SHOWING A SIMILAR IDEA. STORMS THAT
FORM IN NORTH KS MAY STILL HAVE THE POTENTIAL FOR LARGE HAIL GIVEN
STEEP MID LEVEL LAPSE RATES. WITH CONTINUED SOUTHERLY FLOW AND
MOISTURE ADVECTION INTO THE AREA...A STRATUS DECK IS EXPECTED TO
REDEVELOP THIS EVENING. THE CLOUD COVER COMBINED WITH A WARM MOIST
BOUNDARY LAYER SHOULD CREATE A VERY MILD NIGHT WITH LOWS ONLY IN THE
LOWER 60S.
BY TUESDAY...THE MODELS HAVE TRENDED A LITTLE SLOWER WITH THE
FRONTAL PASSAGE AND ONLY BEGIN TO BRING IT INTO THE NORTH CENTRAL
COUNTIES BY LATE AFTERNOON. WITH THE SUBSTANTIAL CAPPING INVERSION
IN THE WARM SECTOR...THINK THAT DEEP MOIST CONVECTION WILL LIKELY
HOLD OFF UNTIL THE FRONT MOVES THROUGH TO LIFT SURFACE PARCELS TO
THE LFC. WITH THE LINEAR FORCING FOR CONVECTION...THUNDERSTORMS MAY
QUICKLY DEVELOP INTO A SQUALL LINE WITH STRONG WINDS AND HAIL THE
MOST LIKELY HAZARD. SO THE FORECAST SHOWS POPS INCREASING LATE IN
THE AFTERNOON ACROSS NORTH CENTRAL KS. SINCE THERE IS NO REAL COLD
AIR ADVECTION TO SPEAK OF THROUGH THE DAY...HIGHS SHOULD AGAIN BE
MILD WITH UPPER 60S TO 70S FROM NORTH CENTRAL KS TO EAST CENTRAL KS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
FOR THE MOST PART THE MAIN SQUALL LINE APPEARS POISED TO MOVE
ACROSS THE FORECAST AREA BETWEEN 00Z AND 06Z DURING THE EVENING
HOURS ON TUESDAY. WARM NOSE AROUND 775MB WILL INHIBIT CONVECTION
IN THE WARM SECTOR AND THINK MOST LOCATIONS WILL NOT SEE ACTIVITY
UNTIL THE FORCING WITH THE FRONT BREAKS THROUGH. MAY HAVE ONGOING
CONVECTION ALONG AND NORTH OF THE WARM FRONT ACROSS NORTHERN
KANSAS AT THE BEGINNING OF THE PERIOD AS WELL. 0-6KM WIND SHEAR
VECTORS GENERALLY 50-60KTS BUT DIRECTIONAL TURNING IS NOT AS
IMPRESSIVE. GIVEN INSTABILITY GENERALLY 800-1200J/KG THINK THAT
MAIN CONCERN WILL BE WINDS WITH THE STORMS AS THE LINE PASSES.
SOME LOCALLY HEAVY RAIN ALSO POSSIBLE AND CANNOT RULE OUT ISOLATED
TORNADOES ALONG THE LINE...BUT AT THIS TIME IS NOT THE PRIMARY
CONCERN. TRAILING RAIN AND ISOLATED T CONTINUE THROUGH THE NIGHT.
NEXT CONCERN IS COLD AIR DIVING SOUTHWARD BEHIND THIS SYSTEM. WARM
NOSE IS INITIALLY SO WARM THINK THAT PRECIP WILL STAY AS RAIN
DESPITE COOLING SURFACE TEMPERATURES...BUT AS THIS NOSE COOLS
THEN MORE COMPLEX PRECIP TYPES COME INTO PLAY. BY THE TIME IT GETS
COLD ENOUGH ALOFT FOR SNOW...THE MOISTURE AND LIFT ARE GENERALLY
EAST OF THE AREA. AS THE COLD AIR AT THE SURFACE GETS COLDER...THE
CHANCE FOR A CHANGEOVER TO SLEET OR FREEZING RAIN ALSO INCREASES.
HAVE STARTED WITH A RAIN SNOW MIX ACROSS THE NORTHWEST...BUT THINK
THIS WILL BE MORE OF A MIXED BAG...WITH LITTLE OF IT STICKING TO
THE GROUND AND ANY ACCUMULATION ON ELEVATED SURFACES. INITIAL
CHANCES FOR MIXED PRECIP ARE NORTH AND WEST OF MANHATTAN AFTER
MIDNIGHT INTO WEDNESDAY MORNING...RETREATING SOMEWHAT BACK INTO
NORTH CENTRAL KANSAS WEDNESDAY AFTERNOON. THE CHANCES THEN SPREAD
EASTWARD WITH A MIX POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING
ACROSS MUCH OF NORTHEAST AND EAST CENTRAL KANSAS. WILL HAVE TO
MONITOR FORECAST SOUNDINGS OVER NEXT FEW RUNS...BUT A QUICK ROUND
OF SOME TYPE OF FREEZING PRECIP LOOKS POSSIBLE FOR NORTH CENTRAL
KANSAS.
THE AIRMASS THAT DROPS INTO THE PLAINS BEHIND THE FRONT HOLDS
HIGHS IN THE 30S AND 40S WEDNESDAY...40S FOR THURSDAY...SLOWLY
RISING TOWARD 50 ON FRIDAY AND BACK TOWARD NORMAL LATER IN THE
WEEKEND. OVERNIGHT LOW TEMPERATURES MAY FALL BELOW FREEZING
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...FINALLY RISING BACK INTO
THE 40S SATURDAY NIGHT. ALTHOUGH THE GROWING SEASON IS SLOW TO
START...ITS WORTH NOTING THAT EARLY EMERGENT VEGETATION WILL SEE
COLD OVERNIGHT LOWS MID TO LATE WEEK. 67
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1211 AM CDT TUE APR 9 2013
FOR 06Z TAFS...AN AREA OF MVFR CIGS OVER CENTRAL AND SOUTHERN KANSAS
IS EXPECTED TO SPREAD EASTWARD OVER THE TAF SITES THROUGH THE
OVERNIGHT HOURS. MODEL SOUNDINGS CONTINUE TO HINT AT THE POTENTIAL
FOR A BRIEF PERIOD OF BORDERLINE IFR/MVFR CIGS AROUND SUNRISE.
OTHERWISE...MVFR CIGS SHOULD PERSIST THROUGH THE DAY WITH THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS INCREASING BY LATE AFTERNOON
AND PERSISTING THROUGH THE EVENING HOURS AS A STRONG COLD FRONT
PASSES WEST TO EAST ACROSS THE TAF SITES. MUCH OF THE PRECIPITATION
IS EXPECTED TO DEVELOP ALONG AND BEHIND THIS FRONT. HAVE ADDED IN
VCTS FOR THE END OF THE PERIOD AND WILL NARROW DOWN THE TIMING IN
FUTURE UPDATES AS CONFIDENCE INCREASES.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1143 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1143 PM CDT MON APR 8 2013
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
UPDATE ISSUED AT 907 PM CDT MON APR 8 2013
HAVE UPDATED TWICE THIS EVENING TO CATCH UP TO TRENDS IN MOST
ELEMENTS. THE RUC SEEMS TO BE HANDLING THE SITUATION QUITE
WELL...SO FOLLOWED IT CLOSELY.
THE FIRST 2 ISSUES ARE THE RAPID SOUTH TO NORTH CLEARING...AND
THE WINDS ARE MUCH LIGHTER THAN MOST GUIDANCE WOULD INDICATE FOR
THE THIRD STRAIGHT NIGHT. OF COURSE THIS BRINGS GREATER
RADIATIONAL COOLING INTO PLAY. THE FINAL TREND OF LOWER 50
DEWPOINTS ADVECTING NORTHWARD OUT OF WEST TENNESSEE LEADS TO MORE
COOLING THAN PREVIOUSLY EXPECTED. KNOCKED LOWS DOWN A
CATEGORY...GENERALLY INTO THE UPPER 50S...BUT WOULD NOT BE SHOCKED
TO SEE A FEW SITES IN WEST KENTUCKY DROP INTO THE MIDDLE 50S.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 329 PM CDT MON APR 8 2013
SREF AND NAM ARE TRENDING DRIER TONIGHT INTO TUESDAY...WHILE GFS
AND ECMWF SHOW WIDESPREAD LIGHT PRECIP LATE TONIGHT AND EARLY
TUESDAY. ECHOES THAT MOVED ACROSS OUR REGION TODAY PRODUCED MAINLY
SPRINKLES AT BEST. SREF AND NAM DID BETTER TODAY...AND IT SEEMS
LEANING TOWARD THE DRIER SOLUTIONS IN THE NEAR TERM IS A BETTER
BET...SO REMOVED POPS FOR TONIGHT AND TUESDAY. A STRAY SHOWER
ACROSS MAINLY OUR NORTHERN COUNTIES IS NOT OUT OF THE
QUESTION...BUT CHANCES JUST ARE NOT GOOD ENOUGH TO WARRANT A POP
AT THIS POINT.
THE LOW PRESSURE SYSTEM WILL BE MOVING CLOSER BY TUESDAY
NIGHT...AND MODELS ARE IN PRETTY GOOD AGREEMENT KEEPING OUR REGION
DRY THROUGH MIDNIGHT. DID INCLUDE SLIGHT CHANCE POPS FOR OUR
EXTREME WESTERN COUNTIES TUESDAY EVENING TO BETTER BLEND WITH OUR
NEIGHBORS. AFTER 06Z...MODELS SPREAD SOME LIGHT QPF INTO MUCH OF
SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI. WENT WITH LIKELY POPS
FAR WEST TO CHANCE AND SLIGHT CHANCE ACROSS MUCH OF SOUTHERN
ILLINOIS AND A GOOD PORTION OF SOUTHEAST MISSOURI...THOUGH QPF
AMOUNTS DO NOT LOOK TOO SIGNIFICANT AT THIS POINT.
TEMPERATURES WILL REMAIN UNSEASONABLY WARM THROUGH THE PERIOD.
LEANED ON THE WARM SIDE OF GUIDANCE FOR LOWS AND THE COOLER SIDE OF
GUIDANCE FOR HIGHS BASED ON WINDS STAYING UP AND EXPECTED CLOUD
COVER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 329 PM CDT MON APR 8 2013
THE MAIN FOCUS IN THIS TIME FRAME WILL COME WITH THE MID WEEK COLD
FRONT AND MID LEVEL SHORT WAVE THAT WILL BE APPROACHING THE MS RIVER
VALLEY LATE WED AND WED NIGHT. DETERMINISTIC MODEL RUNS OF THE
GFS/ECMWF ARE STILL NOT IN GOOD ENOUGH AGREEMENT REGARDING THE
TIMING OF THESE FEATURES TO HAVE A HIGH DEGREE OF CONFIDENCE AS TO
THE DEGREE OVER LOW LEVEL INSTABILITY THAT WILL BE AVAILABLE ONCE
THE FRONT ENTERS THE FORECAST AREA. THE OPERATIONAL GFS CONTINUES
TO BE THE QUICKEST/MOST PROGRESSIVE MODEL...THO IT HAS TRENDED
SLOWER FROM THE OVERNIGHT RUN. THUS...HAVE OPTED TO FOLLOW HPC/WPC
THOUGHTS AND SIDE A BIT MORE TOWARD THE SLOWER/MORE CONSISTENT 12Z
EURO RUN WITH THIS PACKAGE.
WITH THAT SAID...IT LOOKS AS THOUGH THE MAIN PUSH OF POTENTIAL
SEVERE STORMS AND/OR HEAVY RAINFALL WILL COME ALONG AND JUST BEHIND
THE COLD FRONT WED EVENING OVER SE MO...THEN LATER WED EVE INTO THE
OVERNIGHT AND EARLY AM HOURS THU EAST OF THE MS RIVER. EVEN THO LOW
LEVEL INSTABILITY WILL WANE DURING THE NIGHT TIME HOURS...IT STILL
APPEARS THAT AT LEAST MODEST INSTABILITY WILL PERSIST AHEAD OF THE
FRONT...ALONG WITH QUITE IMPRESSIVE 0-1 KM SHEAR/HELICITY VALUES.
WITH SFC DEW POINTS EXPECTED TO RISE/POOL INTO THE MID 60S JUST
AHEAD OF THE SFC FRONT....WILL NOT TAKE MUCH INSTABILITY TO SUPPORT
AT LEAST ISOLATED SEVERE WINDS AND POSSIBLY A COUPLE OF TORNADOES
WED NIGHT JUST AHEAD OF THE SFC FRONT AS IT APPROACHES. AT THIS
TIME...WOULD NOT BE AT ALL SURPRISED IF WE END UP WITH TOR WATCH
BOXES STACKED FROM WEST TO EAST ACROSS THE FORECAST AREA WED EVENING
INTO EARLY THU.
THEREAFTER...RAIN FREE CONDITIONS ARE EXPECTED FOR THE LATE
WEEK/WEEKEND TIME FRAME AS HIGH PRESSURE TAKES OVER. AFTER A BRIEF
CHILL BEHIND THE FRONT THU/THU NIGHT...SOUTHERLY WINDS SHOULD RETURN
IN THE FRI THRU SUN TIME FRAME...AND BRING US BACK INTO THE 60S AND
70S IN TIME FOR THE WEEKEND.
&&
.AVIATION...
ISSUED AT 1143 PM CDT MON APR 8 2013
TRIED TO MODEL THE 06Z TAFS AFTER THE TRENDS FROM TODAY. GUIDANCE
CANNOT HANDLE THE LOW-LEVEL MOISTURE...AND IT HAS BEEN CHRONICALLY
TOO WINDY AT NIGHT. THE 5-6KFT CLOUDS HAVE LIFTED NORTHWARD AND
ARE NOT CURRENTLY IMPACTING ANY TERMINALS. THERE IS AN AREA OF
MVFR CEILINGS IN EAST TEXAS THAT IS SURE TO MOVE NORTHWARD TOWARD
OUR REGION OVERNIGHT...BUT FEEL THAT THEY...AS HAS BEEN THE CASE
LATELY...WILL BE AT VFR LEVELS WHEN THEY ARRIVE HERE. THE OTHER
CONCERN OVERNIGHT IS LLWS. KLZK VAD WIND PROFILE HAS 50KTS AT
2KFT...BUT KPAH IS HOLDING AT 35KTS. DID NOT MENTION IT WITH THIS
ISSUANCE...BUT IT WILL NEED TO BE MONITORED CLOSELY...ESPECIALLY
GIVEN THE LIGHT SURFACE WINDS.
FOR TUESDAY WILL EXPECT TO SEE CEILINGS AT LEAST THROUGH THE
MORNING IN THE 4-6KFT LAYER...AND A REPEAT OF THE GUSTY SOUTH
SOUTHWEST WINDS WE HAVE HAD FOR THE PAST FEW DAYS. SOME GUSTS
20-25KTS WILL BE POSSIBLE AT ALL SITES THROUGH THE DAY...WITH THE
HIGHEST GUSTS OCCURRING WHEN AND WHERE BETTER MIXING/MORE SUNSHINE
OCCURS. FOLLOWING THE OBSERVATIONS FROM THE LAST 2 NIGHTS...WILL
LIKELY SEE WINDS DROP OFF TO AROUND 5KTS ALL SITES WITH
SUNSET...AND SOME GUIDANCE ACTUALLY SHOWS SCATTERING OF THE LOWER
CLOUDS...SO WILL NOT CARRY ANY CEILINGS FOR TUESDAY EVENING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...RST
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
530 AM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP
CUTOFF OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO PERSIST THROUGH TUE MORNING AT ALL SITES. AS
DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND IWD...CONDITIONS
WILL IMPROVE TO VFR AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND 25
KT TUE INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT BEFORE DIMINISHING BACK TO 25 KT ON FRIDAY. WINDS ARE
EXPECTED TO DIMINISH BLO 20 KTS FRI NIGHT INTO SAT AND HIGH PRES
BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 AM EDT TUE APR 9 2013
.UPDATE...
ISSUED AT 901 PM EDT MON APR 8 2013
LOW LEVEL MOISTURE WILL CONTINUE TO REMAIN TRAPPED AS PRECIPITATION
HAS JUST ABOUT ENDED. THIS HAS CAUSED AREAS OF DENSE FOG TO FORM
OVER THE HIGHLANDS OF WESTERN UPPER MICHIGAN WITH VISIBILITIES BELOW
ONE QUARTER MILE. CONDITIONS WILL NOT IMPROVE OVERNIGHT AND ISSUED A
DENSE FOG ADVISORY FOR THIS ACROSS THE FAR WEST AND NORTH CENTRAL
COUNTIES. UPSLOPE WINDS OUT OF THE NORTH TO NORTHWEST WILL CONTINUE
TO BRING IN LOW LEVEL MOISTURE FROM LAKE SUPERIOR ALSO.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO PERSIST THROUGH TUE MORNING AT ALL SITES. AS
DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND IWD...CONDITIONS
WILL IMPROVE TO VFR AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN
BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH.
PRES GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
156 AM EDT TUE APR 9 2013
.UPDATE...
ISSUED AT 901 PM EDT MON APR 8 2013
LOW LEVEL MOISTURE WILL CONTINUE TO REMAIN TRAPPED AS PRECIPITATION
HAS JUST ABOUT ENDED. THIS HAS CAUSED AREAS OF DENSE FOG TO FORM
OVER THE HIGHLANDS OF WESTERN UPPER MICHIGAN WITH VISIBILITIES BELOW
ONE QUARTER MILE. CONDITIONS WILL NOT IMPROVE OVERNIGHT AND ISSUED A
DENSE FOG ADVISORY FOR THIS ACROSS THE FAR WEST AND NORTH CENTRAL
COUNTIES. UPSLOPE WINDS OUT OF THE NORTH TO NORTHWEST WILL CONTINUE
TO BRING IN LOW LEVEL MOISTURE FROM LAKE SUPERIOR ALSO.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO PERSIST THROUGH TUE MORNING AT ALL SITES. AS
DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND IWD...CONDITIONS
WILL IMPROVE TO VFR AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN
BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH.
PRES GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 AM CDT TUE APR 9 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECASTED SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1159 PM CDT MON APR 8 2013
TRICKY FORECAST WITH RESPECT TO PRECIPITATION TYPES...BUT
CONFIDENCE IS HIGH IN A PROLONGED PERIOD OF LOW-END MVFR TO IFR
CONDITIONS ACROSS ALL TAF SITES LATE TONIGHT THROUGH WEDNESDAY
MORNING...AND EVEN BEYOND. SLOW LUMBERING LOW PRESSURE SYSTEM
COMING OUT OF THE FOUR CORNERS REGION WILL SPREAD A LARGE SWATH OF
MOISTURE ACROSS THE REGION OVERNIGHT. PRECIPITATION WILL COME
MOSTLY IN THE FORM OF RAIN FOR EASTERN-SOUTHERN MN INTO WESTERN
WI...BUT WESTERN MN WILL SEE A MIX OF WINTRY PRECIP TYPES THROUGH
THE DAY TDA. KAXN HAS A BEST SHOT AT PROLONGED PERIODS OF -SN
WHILE KSTC WILL SEE THE MOST MIXED PRECIP IN THIS TAF CYCLE. THE
REMAINING TAF SITES WILL REMAIN PRIMARILY AS RAIN...LGT TO MOD
INTENSITY. MORE OF A RAPL/RASN MIXTURE WILL DEVELOP LATE TUES EVE
THRU WED MRNG. HAVE KEPT CIGS FAIRLY LOW...MOSTLY IN THE IFR
RANGE...WHILE VSBY ARE NOT EXPECTED TO BE LOWER THAN 2SM...THOUGH
WHERE -SN OCCURS VSBY CAN EASILY BE LOWER. WINDS WILL REMAIN
STRONG OUT OF THE NE...WHICH MAY CAUSE ADDITIONAL VSBY ISSUES IF
-SN IS THE PREDOMINANT PRECIP TYPE.
KMSP...CIGS HAVE RISEN TO OVC024 SO HAVE INITIALIZED AS SUCH IN
THE 09/06Z TAF. HOWEVER...AS ADDITIONAL LOW LEVEL MOISTURE IS
ADVECTED INTO THE REGION IN ADVANCE OF THE LARGE LOW PRES
SYSTEM...CIGS ARE EXPECTED TO LOWER UNDER THE 1700 FT THRESHOLD
OVERNIGHT AND REMAIN THERE THROUGH THE MORNING PUSH. PRECIP LOOKS
TO MOVE IN ARND DAYBREAK...BUT IS EXPECTED TO BE ALL LIQUID.
PERIODS OF MOD RAIN ARE EXPECTED MID-LATE MRNG...THEN TAPER OFF
LATE IN THE DAY. AS COLDER AIR WORKS INTO THE REGION...A WINTRY
MIX OF PRECIP IS EXPECTED LATE TNGT THRU WED MRNG WITH CEILINGS
BOUNCING BETWEEN LOW-END MVFR AND IFR RANGES. WINDS TO REMAIN FROM
030-050 IN THE 15G25KT AREA.
/OUTLOOK FOR KMSP/
WED...IFR CIGS/MVFR VSBYS WITH SN BR. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 20G30 KTS.
FRI...VFR OR BECOMING VFR IN THE MORNING NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...JC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1201 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 935 PM CDT MON APR 8 2013
00Z SOUNDINGS INDICATE VERY WARM MID LEVEL TEMPS SURGED INTO
MISSOURI LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH LATEST
ACARS SOUNDINGS SUGGESTING THIS WARMING HAS REACHED AS FAR E AS
STL AREA. THIS DATA...COMBINED WITH LATEST SHORT-RANGE GUIDANCE...WOULD
CERTAINLY SUGGEST THAT EML WILL BE CAPPING ANY CONVECTION TRYING
TO FORM AOB 700 MB ALONG AND SOUTH OF AN MBY-STL-SLO LINE. IN N/NE
PARTS OF OUR CWA MESOANALYSIS IS INDICATING SOME WEAK LOW LEVEL
CONVERGENCE...AND SINCE CAPPING ISN`T AS INTENSE HAVE CONTINUED
SOME LOW POPS HERE UNTIL THE PREDAWN HOURS...WHEN FORCING/LIFT
TIED TO INCREASE OF LOW LEVEL JET WILL COMMENCE. HOWEVER...EVEN
THEN THE BEST FORCING WITH THIS FEATURE WILL BE FURTHER N ACROSS
IOWA/N IL...SO HAVE ADJUSTED PRECIP THREAT A BIT TO CONFINE
LIKELY POPS TO AREAS N OF UIN.
FORECAST IS PROCESSING AND WILL BE OUT IN A SECOND.
TRUETT
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE BOUNDARY LAYER HAS CONTINUED TO MOISTEN TODAY WITH SURFACE DEW
POINTS CURRENTLY IN THE MID 50S TO LOWER 60S. THIS MOISTURE COMBINED
WITH HEATING HAS RESULTED IN MODEST INSTABILITY WITH SBCAPES OF
AROUND 1200-1700 J/KG. SPC MESOANALYSIS SHOWS THERE IS ONLY WEAK
CIN ACROSS THE NRN 2/3RDS OF THE CWA AND MOST OF THE REGION HAS
EXTENSIVE CU. DESPITE THIS...THE APPARENT LACK OF A LOW LEVEL
FORCING MECHANISM/BOUNDARY HAS INHIBITED CONVECTION. MODEL QPFS
ARE OF LITTLE USE EARLY IN THE PERIOD OWING TO OVERDONE SURFACE
DEW POINTS AND INSTABILITY AND CONVECTIVE PCPN WITHIN THE MODELS.
THIS INCLUDES THE EXPLICIT CONVECTION ALLOWING MODELS. THE LATEST
SATELLITE IMAGERY SUGGESTS THE DEEPEST AND MOST AGITATED CU FIELD
RESIDES ACROSS NORTHERN MO INTO WEST CENTRAL IL AND THIS IS WHERE
THE HIGHEST POPS WILL BE FORECAST THIS EVENING. WATER VAPOR
IMAGERY AND THE RUC SHOWS SOME MINOR MID LEVEL PURTURBATIONS
UPSTREAM ACROSS THE PLAINS WHICH WILL SKIRT THIS REGION LATER
TONIGHT AND THUS NORTHERN MO INTO WEST CENTRAL IL WILL HAVE THE
HIGHEST POPS OVERNIGHT AS WELL. OVERNIGHT LOWS WILL BE QUITE MILD.
TUESDAY IS EXPECTED TO BE LARGELY DRY. THERE COULD BE SOME
RESIDUAL SHOWERS AND THUNDERSTORMS ACROSS THE FAR NORTHERN CWA IN
THE MORNING...HOWEVER THE ABSENCE OF A FOCUSING BOUNDARY AND A
STRENGTHENING EML SUGGESTS ANY OTHER CONVECTIVE POTENTIAL WILL BE
QUITE LOW AND ISOLATED. MORE IMPORTANTLY WE WILL SEE YET ANOTHER
DAY OF SEASONABLY WARM TEMPERATURES. DESPITE A GOOD DEAL OF
CU...HIGHS SHOULD RISE INTO MID 70S TO LOWER 80S.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE PERIOD FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT STILL APPEARS TO
BE QUITE ACTIVE. STILL THINKING THAT DISCRETE STORMS/CLUSTERS THAT
DEVELOP ALONG THE PLAINS COLD FRONT AND DRYLINE IN THE AFTERNOON
WILL QUICKLY GROW UPSCALE INTO A LINE/QLCS CONSIDERING THE DEEP
LAYER SHEAR VECTORS WITH ONLY A SMALL ANGLE FROM THE
BOUNDARY/FORCING. THE UPPER TROF WILL BE ONLY SLOWLY PROGRESSIVE
AS IT BECOMES MORE ELONGATED WHEN THE INITIAL UPPER LOW LIFTS NNE
AND ANOTHER SHORTWAVE DIGGS THRU THE BASE. THE NET EFFECT IS
BACKING OF THE UPPER LEVEL FLOW AND POTENTIAL SLOWING OF THE
EASTWARD MOVEMENT OF THE LINE/QLCS OVERNIGHT TUESDAY. THE NAM/CMC
GEM HAVE SLOWED CONSIDERABLY...HOWEVER THE ECMWF AND GFS CONTINUE
TO HAVE A GOOD DEAL OF QPF INTO EASTERN MO. WITH THIS IN MIND I
HAVENT MADE ANY RADICAL CHANGES. AMPLE INSTABILITY AND STRONG DEEP
LAYER SHEAR CONTINUE TO SUPPORT A SEVERE THREAT WITH ANY
THUNDERSTORMS. THE OVERALL EVOLUTION OF STORMS ON WED/WED NIGHT IS
A BIT UNCERTAIN DUE TO UNKNOWNS OF THE OVERNIGHT STORMS ON TUESDAY
NIGHT. THE COLD FRONT WILL BE SLOWLY MOVING ACROSS THE AREA AND
DEEP LAYER FORCING BOTH AHEAD AND BEHIND THE FRONT WILL BE
INCREASING THROUGH THE DAY AS HEIGHT FALLS SPREAD ACROSS THE AREA.
THIS SHOULD TRANSLATE TO WIDESPREAD COVERAGE OF STORMS BOTH ALONG
THE FRONT AND SHOWERS AND STORMS IN THE COOLER AIR. DEEP LAYER
SHEAR WILL BE STRONG AND THE DEGREE OF SEVERE WEATHER IN THE WARM
SECTOR WILL BE LARGELY DICTICATED BY THE AMOUNT OF INSTABILITY
WHICH WILL BE PRESENT...WHICH IS COMPLICATED BY CLOUD COVER AND
ONGOING STORMS IN THE MORNING. WE WILL ALSO HAVE TO KEEP AN EYE ON
ANY HEAVY RAINFALL POTENTIAL GIVEN THE SLOW MOVEMENT AND HIGH
MOISTURE CONTENT OF THE ATMOSPHERE.
MUCH COOLER CONDITIONS ARE EXPECTED ON THURSDAY WITH EXTENSIVE
CLOUDINESS WITHIN THE CYCLONIC FLOW IN THE WAKE OF THE FRONT. THE
PRESENCE OF A TRAILING VORT MAX AND COLD AIR ALOFT ALSO SUGGESTS A
CHANCE OF INSTABILITY SHOWERS. THE BELOW AVERAGE TEMPERATURES WILL
PERSIST FRIDAY WITH A SLIGHT MODERATION ON SATURDAY. TEMPERATURES
SHOULD WARM TO ABOVE AVERAGE SUNDAY INTO MONDAY AS THE FLOW ALOFT
TRANSITIONS TO QUASI-ZONAL AND SOUTHERLY LOW LEVEL FLOW GETS
UNDERWAY.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1137 PM CDT MON APR 8 2013
STILL THINKING THAT THERE COULD BE A FEW STORMS LATER TONIGHT OVER
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS...THOUGH
PROBABILITIES ARE LOOKING LOWER AND LOWER AS THE NIGHT CONTINUES.
ALSO...VFR CIGS CONTINUE TO CLEAR FROM SOUTH TO NORTH THROUGH THE
MISSISSIPPI VALLEY. THINK VFR CONDITIONS WILL PREVAIL ALONG AND
EAST OF THE MISSISSIPPI...AND THE 4000-5000FT DECK MAY CLEAR OUT
ENTIRELY. STILL COULD SEE SOME HIGH MVFR CIGS IN CENTRAL AND
NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS...ESPECIALLY IF IT RAINS
UP NORTH. ANY MVFR CIGS THAT DO FORM SHOULD SCATTER AND LIFT
TUESDAY AS DAYTIME HEATING MIXES THE LOWER ATMOSPHERE. WIND WILL
BECOME SOUTHERLY AND GUSTY BY LATE MORNING/EARLY AFTERNOON WITH
VFR FLIGHT CONDITIONS CONTINUING. NEXT CHANCE FOR PRECIP WILL MOST
LIKELY BE LATE TUESDAY EVENING.
SPECIFICS FOR KSTL...
EXPECT VFR FLIGHT CONDITIONS TO PREVAIL FOR THE REST OF THE NIGHT
AT LAMBERT. 4000-5000FT CIGS LOOK LIKE THEY MAY EVEN CLEAR FROM
THE SOUTH LATER TONIGHT...BUT AM NOT THAT CONFIDENT THAT THE LOW
LEVEL JET WON`T CONTINUE TO KEEP MOISTURE AND CLOUDS GOING.
SOUTHEAST WIND WILL BECOME SOUTHERLY BY MID-MORNING AND GUSTS TO
AROUND 25KTS LOOK LIKELY. NEXT CHANCE FOR PRECIP LOOKS LIKE IT
COULD BE AS EARLY AS MID-LATE TUESDAY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
417 AM CDT TUE APR 9 2013
.DISCUSSION...
VERY ACTIVE WEATHER WILL CONTINUE OVER THE NEXT 24-36 HOURS WITH
NUMEROUS WEATHER ELEMENTS IN OUR FORECAST.
CONVECTION IS UNDERWAY ACROSS THE REGION ALONG A SLOWLY SOUTHWARD
SAGGING BOUNDARY EXTENDING FROM SURFACE LOW PRESSURE CENTERED OVER
NORTHEAST NEW MEXICO THROUGH NORTHWEST KANSAS...INTO EAST CENTRAL
NEBRASKA AND ACROSS CENTRAL IOWA. FOR THE MOST PART...CONVECTION HAS
REMAINED ALONG AND NORTH OF THE BOUNDARY BUT SOME SCATTERED ACTIVITY
HAS BEEN ABLE TO DEVELOP IN THE WARM SECTOR ACROSS SOUTH CENTRAL
NEBRASKA. 850MB MOISTURE IS PLENTIFUL WITH 45-50KT SOUTHERLY LOW
LEVEL JET TRANSPORTING NEARLY +12C DEWPOINTS INTO THE SOUTHERN CWA.
SHORT RANGE MODEL INDICATIONS ARE FOR A CONTINUATION OF EASTWARD
PROPAGATION ALONG THE BOUNDARY WITH SOME TRAINING OF STORMS
POSSIBLE. PW`S REMAIN AROUND 1". A FEW OF THE NEAR TERM CONVECTIVE
MODELS...INCLUDING THE 01Z HRRR...INDICATE A TRANSITION FROM
SCATTERED CELLS TO A BOWING SEGMENT OF SORTS PUSHING INTO EASTERN
NEBRSAKA OVER THE NEXT COUPLE HOURS. THIS WILL WILL NEED TO BE
WATCHED CLOSELY EARLY THIS MORNING. ANY STORMS THAT DO REACH SEVERE
LIMITS WOULD BE CAPABLE OF PRODUCING DAMAGING WIND AND MAYBE SOME
LARGE HAIL...BUT MAINLY HEAVY RAIN.
SHORTWAVE MID LEVEL RIDGING WILL PUSH NORTHEAST ACROSS THE CWA TODAY
AS THE SURFACE BOUNDARY PUSHES A BIT FURTHER EAST WHILE THE SFC LOW
MOVES INTO THE TEXAS PANHANDLE. WIDESPREAD PRECIPITATION IS
POSSIBLE OVER MUCH OF CENTRAL AND NORTHEAST NEBRASKA THROUGHOUT THE
DAY ON THE COLD SIDE OF THE SURFACE BOUNDARY. CONVECTION IS EXPECTED
TO REDEVELOP IN THE WARM SECTOR AS INSTABILITY INCREASES AND REGION
IS IN A SLIGHT RISK FOR THE DAY ONE OUTLOOK. MEANWHILE...OUR FAR
NORTHWESTERN COUNTIES WILL BE UNDER THE GUN FOR A FREEZING
RAIN/SLEET SCENARIO AS A WARM NOSE OF 850MB AIR WRAPS NORTHWEST
INTO THE SYSTEM WHILE THE COLD AIR UNDERCUTS THIS AT THE SURFACE.
THERE APPEARS TO BE ABOUT A 24 HOUR PERIOD OF THE POTENTIAL FOR
FREEZING RAIN AND/OR SLEET ACROSS A FEW COUNTIES IN OUR
NORTHWEST...WITH THE POTENTIAL FOR ACCUMULATING SNOW OF AROUND
2-4". AS A RESULT...HAVE UPGRADED THE WATCH TO A WARNING FOR
ANTELOPE AND KNOX COUNTIES AND CONVERTED THE WATCH TO AN ADVISORY
FOR THE NEXT TIER OF COUNTIES SOUTHEAST OF KNOX AND ANTELOPE.
USING THE TOP DOWN METHOD WOULD GIVE US A 24 HOUR PERIOD OF
FREEZING RAIN/SLEET AT KOFK...WITH UP TO A TENTH OF AN INCH OF ICE
POSSIBLE AND HOPEFULLY NOT MORE. GFS/SREF/NAM ALL SHOW THIS. THE
SREF ALSO PAINTS A 50% PROBABILITY OF MEASURABLE FZRA STRIPE
ACROSS A GOOD PORTION OF NORTHEAST NEBRASKA. THE NOSE OF WARM AIR
AROUND 850MB WILL SLOWLY COOL BELOW FREEZING FROM NORTHWEST TO
SOUTHEAST ACROSS THE CWA TURNING THIS MIX OVER TO SNOW BY MID DAY
WEDNESDAY. THIS TIME PERIOD IS QUITE CHALLENGING AS SFC
TEMPERATURES MAY RISE ABOVE FREEZING AND WITH THE STRONG APRIL SUN
ANGLE...IT MAY BE DIFFICULT TO REMAIN COLD ENOUGH FOR WINTERY
PCPN. THERE ARE MANY VARIABLES GOING INTO THIS EVENT AND ANY ONE
THAT VARIES BY A DEGREE OR TWO CAN DRAMATICALLY CHANGE THE
PRECIPITATION TYPE. THE EVOLUTION OF THIS ENTIRE SCENARIO WILL BE
WATCHED CLOSELY AND UPGRADES/DOWNGRADES TO HEADLINES ARE POSSIBLE
AS THIS EVENT UNFOLDS. IN ADDITION TO THE PCPN...NORTH WINDS WILL
BE QUITE BREEZY AND COULD BE AN ISSUE FOR POWERLINES AND TREES IF
THEY ACCUMULATE ANY ICE.
KERN
&&
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK.
PERIODS OF SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE AREA
THROUGH 10Z WITH LIFR CONDITIONS CONTINUING AT KOFK AND DEVELOPING
AT KOMA AND KLNK THROUGH 12Z. FREEZING RAIN LIKELY AT KOFK AFTER
15Z. LATEST RAP MODEL SHOWS WARM FRONT REMAINING NORTHWEST OF
KOMA AND KLNK THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM CDT
WEDNESDAY FOR NEZ012-017-030-031.
WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM CDT
WEDNESDAY FOR NEZ011-016.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
215 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1051 PM CDT MON APR 8 2013
UPDATED FORECAST FOR EARLIER ONSET OF WINTER WEATHER CONDITIONS
OVER NORTHWEST NEBRASKA. TRANSITION TO SNOW TO THE WEST OF A LINE
FROM CODY TO LISCO.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
DEEP CONVECTION SHOULD DEVELOP WEST TO EAST TONIGHT WITH LARGE HAIL
THE PRIMARY SEVERE WEATHER THREAT. THERE IS A NARROW WINDOW FOR
TORNADOES ASSOCIATED WITH A SOUTHWARD MOVING COLD FRONT THIS EVENING
AND STORMS DEVELOPING ALONG OR JUST SOUTH OF THE FRONT. THE
THUNDERSTORMS WILL HELP PULL COLD AIR SOUTH WHICH COULD CAUSE A
CHANGEOVER TO FREEZING RAIN FASTER THAN FORECAST.
THE RAP HAS WEAKENED THE MIDLEVEL WARM AIR ADVECTION SUFFICIENTLY TO
REDUCE THE RISK OF SLEET HOWEVER THIS WOULD SUGGEST MORE FREEZING
RAIN OR FREEZING DRIZZLE POTENTIAL TUESDAY AS THE MOISTURE IS
GENERALLY BELOW 700 MB IN ALL MODELS. THE LATEST FORECAST SHOWS LESS
QPF TUESDAY BUT SOME AREAS COULD SEE BETWEEN 1/4 AND 1/2 INCH OF
FREEZING RAIN AS THE CHANGEOVER LINE WILL SPEND MOST OF THE DAY
HOURS TRAVERSING EASTERN PORTIONS OF THE FCST AREA.
THE SNOW LINE IS A LITTLE FASTER IN THE RAP BUT THE RAIN TO FREEZING
RAIN LINE SHOULD BE DRAPED ACROSS CUSTER AND FRONTIER COUNTY BY 12Z
TUESDAY. ALL OF THIS SUGGESTS THE COLD AIR IS WINNING OUT IN THE
WEST AND TAKING A MORE NORTH TO SOUTH PLUNGE. THERE NO REAL CHANGE
IN THE SNOWFALL AMOUNTS DURING THE SHORT TERM EXCEPT HIGHER AMOUNTS
ASSOCIATED WITH THE SLIGHTLY FASTER CHANGEOVER IN THE WEST.
ICING COULD BE A REAL PROBLEM FOR THE POWER GRID IN SOME AREAS WITH
WINDS INCREASING TO 25 TO 35 MPH. TEMPERATURES SHOULD BE STEADY OR
FALLING IN THE 20S THROUGHOUT THE DAY AND WIND CHILL READINGS IN THE
SINGLE DIGITS ARE EXPECTED ALL AREAS BY TUESDAY NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
EARLY TUESDAY EVENING THE H5 UPPER LOW IS FORECAST TO ROTATE INTO
CENTRAL COLORADO WHILE THE H7 LOW MOVES INTO FAR NORTHEAST CO/SWRN
NEBR/NWRN KS. THIS WILL BE CONDUCIVE FOR A PERIOD OF MODERATE TO
HEAVY SNOW IS TO DEVELOP IN NW KS AND DRAWN NORTHWARD INTO
WESTERN NEBRASKA. NORTHWEST WINDS 25 TO 35 MPH AND GUSTY TO
PRODUCE AREAS OF BLOWING SNOW TO DIMINISH SLIGHTLY TO 20 TO 30
MPH AFTER MIDNIGHT. THE SYSTEM WILL BEGIN TO WEAKEN AS DRIER AIR
IS DRAWN INTO THE EASTERN SIDE OF THE SYSTEM. A PERSISTENT
DEFORMATION ZONE ON THE BACKSIDE OF THE SYSTEM WILL STILL BRING
LIGHT SNOW ACCUMULATIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY.
EVEN WEDNESDAY NIGHT INTO THURSDAY...THE NORTHEAST HALF OF THE
AREA MAY CONTINUE TO SEE LIGHT SNOW AS UPPER LOW ROTATES SLOWLY
EAST INTO IOWA.
HAVE TRENDED DOWN HIGH TEMPERATURES WEDNESDAY TO THE UPPER 20S AND
LOWER 30S. THURSDAY HIGHS ALSO TRENDED DOWN A BIT TO 33 TO 35
NORTH CENTRAL TO THE LOWER 40S FAR SOUTHWEST.
IN WAKE OF CLOSED SYSTEM THURSDAY...UPPER FLOW WILL BE WEST
NORTHWEST FRIDAY THROUGH MONDAY. TEMPERATURES TO MODERATE FROM
40 TO 50 FRIDAY TO THE 50S TO LOW/MID 60S SATURDAY AND SUNDAY. LOW
CHANCE POPS SUNDAY/MONDAY FOR RAIN SHOWERS...NIGHTTIME/MORNING
RAIN/SNOW SHOWERS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 214 AM CDT TUE APR 9 2013
WIDESPREAD SNOW IS EXPECTED TO MOVE INTO NORTHWEST NEBRASKA BY 09Z
AND SLOWLY SPREAD INTO NORTH CENTRAL BY 12Z. IN THE
MEANTIME...SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE SOUTH AND
EAST OF AN ONL-OGA LINE UNTIL AT LEAST 08Z. THEN WIDESPREAD RAIN IN
CENTRAL AND SOUTHWEST NEBRASKA WILL GRADUALLY CHANGE OVER TO SNOW
LATE MORNING AND DURING THE AFTERNOON. THE CHANGE TO SNOW IS LIKELY
AT LBF...OGA AND IML BETWEEN 18Z AND 21Z. IT WILL BE LATE EVENING
BEFORE IT CHANGES TO SNOW IN ONL AND BBW.
WIND IS OF MAJOR CONCERN WITH 350-040 AT 25-34G34-47KT THROUGH AT
LEAST LATE AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ029-038-058-069>071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ006>010-024>028-035>037-056-057-059.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ004-005-022-023-094.
&&
$$
UPDATE...POWER
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1227 AM CDT TUE APR 9 2013
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK.
PERIODS OF SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE AREA
THROUGH 10Z WITH LIFR CONDITIONS CONTINUING AT KOFK AND DEVELOPING
AT KOMA AND KLNK THROUGH 12Z. FREEZING RAIN LIKELY AT KOFK AFTER
15Z. LATEST RAP MODEL SHOWS WARM FRONT REMAINING NORTHWEST OF
KOMA AND KLNK THROUGH 18Z.
&&
.PREV DISCUSSION... /ISSUED 322 PM CDT MON APR 8 2013/
SHORT TERM...TONIGHT THROUGH THURSDAY
STRONG SPRING STORM SYSTEM IS KNOCKING AT OUR DOOR...WITH ACTIVE
WEATHER EXPECTED FOR THE NEXT FEW DAYS. SUBJECTIVE 12Z UPPER AIR
ANALYSIS INDICATES UPPER-LEVEL TROUGH DEEPENING INTO A LOW OVER
THE GREAT BASIN...WITH 500MB HEIGHT FALLS UP TO 150M. ANOTHER
SHORTWAVE WAS ADVANCING ACROSS IA...WITH 70M HEIGHT FALLS
ASSOCIATED WITH IT. UPPER-LEVEL JET WAS STRONGEST ON THE BACK SIDE
OF THE DIGGING UPPER LOW..WITH UP TO 110KT ALONG THE PACIFIC
COAST. MOISTURE AXIS AT 850MB EXTENDED FROM TX THROUGH EASTERN
KS/WESTERN MO AS FAR NORTH AS THE NEB AND IA BORDERS...WTIH A
DEVELOPING LEE LOW IN SOUTEAST CO/OK PANDHANDLE/SOUTHWEST KS. SUB-
0C TEMPS AT 850MB EXTENDED FROM MT THROUGH ND INTO NORTHERNMOST
MN. RAP ANALYSIS AT 19Z INDICATED A SURFACE LOW IN SOUTHEAST
CO/NORTHEAST NM...WITH FRONTAL BOUNDARY EXTENDING FROM SOUTHWEST
NEB THROUGH NORTHEAST NEB AS COLD AIR BEGINS TO DESCEND OUT OF SD
WHILE WARM AIR ADVECTION CONTINUES AHEAD OF THE LOW.
MAIN FORECAST CONCERNS INCLUDE CONVECTIVE POTENTIAL THIS EVENING AND
TONIGHT AND IN THE SOUTHERN CWA THROUGH TUESDAY...AS WELL AS WINTER
WEATHER POTENTIAL IN THE NORTHWEST CWA EARLY TUESDAY MORNING THROUGH
WEDNESDAY. LINGERING CLOUDS ARE INHIBITING WARMING IN THE
SOUTH...WHICH MIGHT MAKE REACHING CONVECTIVE TEMPERATURE A
CHALLENGE. STORMS ARE LIKELY TO FIRE THIS AFTERNOON FURTHER WEST IN
KS...AND MOVE ACROSS NORTHERN KS/SOUTHERN NEB LATER THIS EVENING
THROUGH TONIGHT. MEANWHILE...COLD FRONT DESCENDING OUT OF SD IS
LIKELY TO REACH THE NORTHERN CWA THIS EVENING/TONIGHT...AND SHOULD
BEGIN TO SEE RAIN ALONG THAT FRONT AS WELL. HAVE INCLUDED THUNDER
MENTION EVERYWHERE THIS EVENING...BUT STARTED TO TAKE IT OUT OF THE
NORTHERN CWA AFTER MIDNIGHT. DOES APPEAR THAT SURFACE TEMPS WILL
REMAIN ABOVE FREEZING THROUGH THE NIGHT ACROSS THE AREA...AND THUS
HAVE INDICATED RAIN...BUT SHOULD COLD AIR ARRIVE FASTER THAN
FORECAST...MAY SEE A CHANGE TO WINTRY MIX A LITTLE EARLIER.
COLD AIR ADVECTION WILL CONTINUE TUESDAY IN THE NORTHERN CWA AS
FRONT SLOWLY DIGS THROUGH THE CWA. NORTHWESTERN CWA SHOULD FALL
BELOW FREEZING NEAR THE GROUND BY MID-MORNING TUESDAY...AND WITH
LINGERING MID-LEVEL WARM NOSE...WOULD EXPECT PRECIPITATION TO CHANGE
FROM RAIN TO FREEZING RAIN/SLEET. SOUNDINGS ARE ON THE FENCE ON
WHICH WAY TO GO WITH PRECIP TYPE...AND HAVE INCLUDED A MIX OF BOTH.
OBVIOUSLY...IF ONE PHASE DOMINATES...IMPACTS WILL BE SIGNIFICANTLY
DIFFERENT. DID MOVE BACK TIMING ON WINTER STORM WATCH TO BEGIN AT
12Z IN THE FAR NORTHWEST AND 15Z IN THE REMAINING COUNTIES...BUT
WILL LET THE NEXT SHIFT MAKE AN ASSESSMENT ON TEMPERATURE PROFILES
TO DETERMINE POSSIBLE CONVERSION TO WARNING OR ADVISORY. FURTHER
SOUTH...HAVE INCLUDED THUNDERSTORM MENTION IN THE SOUTHEASTERN CWA
AS FRONT IS LIKELY TO ARRIVE DURING THE AFTERNOON WHEN SOME
DESTABILIZATION HAS OCCURRED.
FOLLOWED MODEL SOUNDINGS PRETTY CLOSELY FOR PRECIP TYPE THROUGH
TUESDAY NIGHT...WITH MORE OF A NAM/SREF FLAVOR LEANING TOWARD
CONTINUED ZR/IP. GFS DID LEAN MORE TOWARD SNOW...BUT FOR NOW...HAVE
LEANED TO THE WARMER MID-LEVEL SOLUTION AS THE SLOW-MOVING SYSTEM
CONTINUES TO ALLOW MID-LEVEL WARM AIR ADVECTION AND TROWALING AHEAD
OF IT. MOST OF THE EASTERN HALF OF THE CWA IS PROGGED TO REMAIN
RAIN THROUGH WEDNESDAY...WHILE PRECIPITATION TRANSITIONS TO A MIX
WITH SNOW IN THE NORTHWEST CWA. DELAYED TRANSITION SHOULD HOLD DOWN
AMOUNTS FOR ANY FROZEN PRECIPITATION ACROSS MOST OF THE CWA...AS
PRECIP AMOUNTS ARE PROGGED TO DIMINISH QUITE A BIT ON WEDNESDAY
NIGHT BY THE TIME TEMPS ARE COLD ENOUGH TO ALLOW SNOW ACROSS THE
REST OF THE CWA. STILL...AS WITH ALL PRECIP TYPE ISSUES...THE LINE
BETWEEN PRECIP TYPES IS THIN...AND CONFIDENCE IS ALWAYS ON THE LOW
SIDE FOR THESE TRANSITIONS. AN EARLIER CHANGEOVER WITH COLDER MID-
LEVELS WOULD PRODUCE MORE SNOW ACROSS THE AREA. PRECIPITATION
SHOULD FINALLY BEGIN TO EXIT THE AREA BY THURSDAY...BUT DID LOWER
TEMPS BY SEVERAL DEGREES ON THURSDAY AS THE COLDEST 850MB TEMPS PASS
OVER THE AREA.
MAYES
LONG TERM...THURSDAY NIGHT THROUGH MONDAY
TEMPERATURES SHOULD BEGIN A MODERATING TREND THROUGH LATE WEEK
AND INTO THE WEEKEND AS UPPER-LEVEL FLOW RETURNS TO ZONAL...WITH
TEMPERATURES RETURNING TO NEAR-NORMAL READINGS FOR THE WEEKEND.
MODEL BLENDS CONTINUE TO GIVE A SLIGHT CHANCE TO SMALL CHANCE OF
PRECIPITATION ON SATURDAY NIGHT THROUGH MONDAYNIGHT...BUT
CONFIDENCE IS VERY LOW AS MODELS CONTINUE TO EXHIBIT SIGNIFICANT
RUN TO RUN VARIABILITY IN THE TIMING OR LOCATION OF ANY RAIN.
PRECIPITATION WOULD NOT BE LIKELY DURING ALL OF THOSE
PERIODS...BUT RATHER OVER A NARROWER WINDOW BETWEEN SATURDAY NIGHT
AND MONDAY NIGHT.
MAYES/BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WATCH FROM 10 AM CDT THIS MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ012-017-030-031.
WINTER STORM WATCH FROM 7 AM CDT THIS MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ011-016.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
247 AM EDT TUE APR 9 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PREVAIL...IN ADVANCE OF A FRONTAL SYSTEM
THAT WILL AFFECT OUR REGION LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 957 PM MONDAY...
WAVE LOCATED OVER WV PRODUCING AN AREA OF MID TO HIGH CLOUDS WILL
TRAVERSE EASTWARD OVERNIGHT... WITH MOST OF THE ASSOCIATED CLOUD
COVER STAYING NORTH OF THE AREA. GFS LOOKS OVERLY AGGRESSIVE SURGING
NEAR 60 DEGREE DEWPOINTS ACROSS THE AREA OVERNIGHT... 00Z OBS
INDICATE DEWPOINTS NEAR 50... MUCH CLOSER TO THE RUC AND NAM
DEPICTIONS. IN THIS CASE... AS WITH LAST NIGHT... BEST LOW LEVEL
MOISTURE AND CHANCES FOR FOG AND LOW STRATUS WILL BE IN THE COASTAL
PLAIN... WITH A FEW PATCHY AREAS POSSIBLE NORTH AND WEST. OVERNIGHT
TEMPERATURES WILL BE A FEW DEGREES WARMER THAN LAST NIGHT... MID
50S... AS TUESDAY 12Z LOW LEVEL THICKNESSES INCREASE AROUND 9 M OVER
THE SAME TIME MONDAY. -SEC
SENSIBLE WEATHER WILL REMAIN WARM AND DRY ACROSS CENTRAL NC AS
SURFACE HIGH ANCHORED OFFSHORE AND A SLOW MOVING LOW PRESSURE SYSTEM
OVER THE SOUTHERN PLAINS MAINTAINS A WARM LOW LEVEL S-SW FLOW OVER
OUR REGION. WLY FLOW BEGINS TO BACK TONIGHT INTO TUESDAY AS A
MID-UPPER LEVEL RIDGE AMPLIFIES NWD OVER THE SE U.S. THIS ADDITIONAL
WARMING ALOFT WILL LEAD TO VERY WARM SFC TEMPS TUESDAY AFTERNOON.
LOW LEVEL THICKNESSES COUPLED WITH A SOUTH-SOUTHWEST BREEZE SUPPORT
AFTERNOON TEMPS NEAR 80 NW TO THE LOWER 80S ELSEWHERE. MIN TEMPS
55-60 TUESDAY NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 230 PM MONDAY...
WEDNESDAY THROUGH THURSDAY:
MID TO UPPER LEVEL RIDGE AXIS IS EXPECTED TO SLOWLY SHIFT OFFSHORE
DURING THIS TIME FRAME... WITH SURFACE HIGH PRESSURE REMAINING
ANCHORED OFFSHORE AND THE NEXT APPROACHING COLD FRONT REMAINING TO
THE WEST OF THE AREA THROUGH THE PERIOD. THIS WILL RESULT IN
CONTINUED ABOVE NORMAL TEMPS... WITH INCREASING CLOUD COVER AND
PRECIP CHANCES BY LATE THURSDAY. STILL EXPECT THE BEST CHANCES FOR
ANY SHOWERS AND OR STORMS TO REMAIN TO THE WEST OF THE AREA THROUGH
THURSDAY AFTERNOON THOUGH... AS THE DEEP TROUGH ALOFT AND ASSOCIATED
COLD FRONT APPROACHES THE AREA FROM THE WEST. HOWEVER... GIVEN
MODELS HAVE TRENDED TO THE FASTER SIDE OF THE GUIDANCE OVER THE PAST
SEVERAL DAYS WITH THIS SYSTEM... WILL GO WITH SLIGHT CHANCE TO LOW
END CHANCE OF SHOWERS AND STORMS FOR LATE THURSDAY AFTERNOON... WITH
THE BEST CHANCE FOR PRECIP EXPECTED OVERNIGHT.
LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PEAK WEDNESDAY AFTERNOON
CLOSE TO 1400 METERS. THIS WILL RESULT IN A WARM AND PARTLY SUNNY
DAY AFTER THE MORNING FOG AND/OR LOW STRATUS BURNS OFF. EXPECT HIGH
TEMPS TO BE IN THE LOWER TO MID 80S... WITH PERHAPS THE WARMEST
TEMPS ACROSS THE NORTHEAST PIEDMONT NEAR THE NC/VA BORDER. LOWS
THURSDAY MORNING WILL HAVE THE SAME FLAVOR... ABOVE NORMAL. EXPECT
LOWS TO BE AROUND 60. HIGHS ON THURSDAY WILL AGAIN BE WARM.
HOWEVER... WE MAY SEE THE STRATUS AND/OR FOG LINGER LONGER AS LOW
MOISTURE IS EXPECTED TO INCREASE FURTHER IN ADVANCE OF THE NEXT
SYSTEM. THUS... WILL GO WITH HIGHS ON THURSDAY IN THE UPPER 70S NW
TO LOWER 80S ELSEWHERE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 245 AM TUESDAY...
THURSDAY THROUGH FRIDAY NIGHT:
A LOW PRESSURE SYSTEM OVER IOWA 12Z THURSDAY WILL MOVE THROUGH THE
GREAT LAKES REGION THROUGH FRIDAY. AN ASSOCIATED COLD FRONT
EXTENDING SOUTHWARD INTO THE GULF COAST WILL PUSH EASTWARD BRINGING
A CHANCE FOR RAIN AND STORMS. THERE ARE STILL SOME TIMING ISSUES
BETWEEN THE MEDIUM-RANGE MODELS WITH REGARD TO THE FROPA AND PRE-
FRONTAL PRECIP. THE GFS...WHICH HAS A TENDENCY TO BRING SYSTEMS
THROUGH A BIT ON THE QUICK SIDE...IS STILL FASTER THAN THE ECMWF...
AND DEPICTS PRECIP STARTING AS EARLY AS 18Z THURSDAY AND EXITING
MOST OF CENTRAL NC BY 18Z FRIDAY. THE ECMWF IS APPROX 12 HOURS
SLOWER WITH THE ONSET AND ABOUT 6 HOURS BEHIND ON EXIT. GIVEN THE
CURRENT UNCERTAINTY....WILL LIKELY CONTINUE TO INTRODUCE RAIN INTO
THE AREA THURSDAY AFT/EVE...ENDING BY 00Z SATURDAY. AS MENTIONED IN
THE PREVIOUS DISCUSSION...THE DURATION OF RAIN WILL LIKELY BE
NARROWED DOWN OVER THE NEXT DAY OR SO IF THE MODELS BEGIN TO SHOW
BETTER AGREEMENT. IF THE BULK OF THE RAINFALL MOVES THROUGH DURING
THE OVERNIGHT HOURS...AS THE GFS SUGGESTS...CHANCES FOR SEVERE
WEATHER WILL BE LIMITED. ALTHOUGH THE MODELS STILL INDICATE MINIMAL
CAPE VALUES...THEY ALSO CONTINUE TO SUGGEST THE PRESENCE OF A STRONG
LOW-LEVEL JET (40-55 KTS AT 925-850 MB) AND DEWPOINTS IN THE LOW TO
MID 60S...WHICH COULD SUPPORT A FEW STRONG TO SEVERE STORMS AHEAD OF
THE FRONT. BOTH THE GFS AND ECMWF STILL SHOW THE PUSH OF COOLER AIR
WITH A SECONDARY COLD FRONT THAN WITH THE INITIAL FROPA. TIMING OF
THE FROPA WILL IMPACT HIGH AND LOW TEMPS FRIDAY AND SATURDAY...BUT
FOR NOW WILL KEEP TEMPS FROM BOTTOMING OUT UNTIL SATURDAY/SATURDAY
NIGHT. HIGHS THURSDAY IN THE UPPER 70S TO LOW 80S...DECREASING A FEW
DEGREES ON FRIDAY...MID TO UPPER 70S. LOWS THURSDAY NIGHT IN THE LOW
TO MID 60S...WITH COLDER OVERNIGHT LOWS EXPECTED ON FRIDAY NIGHT
BEHIND THE SECONDARY COLD FRONT...MID 40S TO AROUND 50 DEGREES.
SATURDAY THROUGH MONDAY:
HIGH PRESSURE WILL BUILD IN BEHIND THE EXITING LOW PRESSURE SYSTEM
ON SATURDAY AND MIGRATE OVER THE AREA THROUGH SUNDAY AND MOVE
OFFSHORE MONDAY. WITH THE COLD AIR ADVECTION BEHIND THE FRONT...
HIGHS ON SATURDAY WILL BE 7-10 DEGREES LOWER THAN FRIDAY ACROSS THE
AREA...MID 60S TO NEAR 70. HOWEVER...SKIES SHOULD BE MOSTLY CLEAR...
ALLOWING FOR PLENTY OF SUNSHINE. WITH THE COLD AIR AND CLEAR SKIES
EXPECT LOWS SATURDAY NIGHT IN THE LOW TO MID 40S. ALTHOUGH CLOUDS
ARE EXPECTED TO INCREASE SUNDAY AFTERNOON INTO MONDAY...SHOULD SEE A
GRADUAL WARMING TREND...WITH HIGHS IN THE LOW TO MID 70S BY MONDAY
AND OVERNIGHT LOWS IN THE MAINLY IN THE MID 40S SUNDAY NIGHT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 155 AM TUESDAY...
A PERSISTENCE FORECAST...OF LIFR CONDITIONS AT KFAY AND MVFR AT KRWI
IN THE SEVERAL HOURS LEADING UP TO 12-13Z...WILL GENERALLY BE
FOLLOWED UNTIL PROVEN OTHERWISE. SLIGHTLY HIGHER DEWPOINTS THIS
MORNING VERSUS PREVIOUS DAYS DOES SUGGEST A BIT HIGHER PROBABILITY
OF THE STRATUS/FOG LAYER EDGING NORTHWESTWARD TO NEAR KRDU THIS
MORNING...HOWEVER...SO WILL MONITOR OBSERVATIONAL TRENDS AND AMEND
AS NEEDED. AFTER STRATUS AND FOG BURN OFF THROUGH 13-14Z...VFR
CONDITIONS...IN SUBSIDENT RIDGING ALOFT AND ASSOCIATED UNDERLYING
INFLUENCE OF BERMUDA SURFACE HIGH PRESSURE...WILL PREVAIL THROUGH
THE END OF THE 06Z TAF PERIOD. SOUTH SOUTHWESTERLY SURFACE WINDS
AROUND THE BERMUDA HIGH WILL CONTINUE...BUT BE SOMEWHAT WEAKER AND
LESS GUSTY (IF AT ALL) THAN PREVIOUS AFTERNOONS OWING TO A SLIGHTLY
WEAKER MSL PRESSURE GRADIENT.
OUTLOOK: BERMUDA HIGH PRESSURE...CHARACTERIZED BY AREAS OF FOG
AND/OR STRATUS EACH MORNING...MAINLY AT KFAY AND KRWI...WILL RULE
THROUGH WED NIGHT. FORECAST GUIDANCE SUGGESTS THE DEPTH OF THE LOW
LEVEL MOISTURE WILL PEAK THU MORNING...AT WHICH TIME DEEPER STRATUS
AT ALL TERMINALS IS LIKELY...FOLLOWED BY A PERIOD MVFR RANGE
CEILINGS BETWEEN 13-19Z THU AS THE MOIST LAYER RISES INTO A CUMULUS
FIELD. THE APPROACH AND PASSAGE OF A FRONTAL SYSTEM WILL THEN RESULT
IN A GOOD CHANCE OF SHOWERS AND STORMS AND ASSOCIATED SUB-VFR
CONDITIONS CENTERED AROUND LATE THU-FRI.
&&
.CLIMATE...
IF TEMPERATURES REACH 80 EARLY THIS WEEK...IT WILL BE THE FIRST
80-DEGREE MAXIMUM TEMPERATURE AT KGSO SINCE OCTOBER 24...AND AT KRDU
SINCE OCTOBER 25. KFAY REACHED 80 MORE RECENTLY...WITH AN 83-DEGREE
HIGH ON MARCH 16. OVER THE LAST COUPLE OF YEARS...THE FIRST
80-DEGREE DAYS HAVE BEEN...
KGSO...MARCH 18 2011...AND MARCH 14 2012.
BOTH KRDU AND KFAY...FEBRUARY 27 2011...AND MARCH 1 2012.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...SEC/WSS
SHORT TERM...BSD
LONG TERM...KC
AVIATION...MWS
CLIMATE...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
159 AM EDT TUE APR 9 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PREVAIL...IN ADVANCE OF A FRONTAL SYSTEM
THAT WILL AFFECT OUR REGION LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 957 PM MONDAY...
WAVE LOCATED OVER WV PRODUCING AN AREA OF MID TO HIGH CLOUDS WILL
TRAVERSE EASTWARD OVERNIGHT... WITH MOST OF THE ASSOCIATED CLOUD
COVER STAYING NORTH OF THE AREA. GFS LOOKS OVERLY AGGRESSIVE SURGING
NEAR 60 DEGREE DEWPOINTS ACROSS THE AREA OVERNIGHT... 00Z OBS
INDICATE DEWPOINTS NEAR 50... MUCH CLOSER TO THE RUC AND NAM
DEPICTIONS. IN THIS CASE... AS WITH LAST NIGHT... BEST LOW LEVEL
MOISTURE AND CHANCES FOR FOG AND LOW STRATUS WILL BE IN THE COASTAL
PLAIN... WITH A FEW PATCHY AREAS POSSIBLE NORTH AND WEST. OVERNIGHT
TEMPERATURES WILL BE A FEW DEGREES WARMER THAN LAST NIGHT... MID
50S... AS TUESDAY 12Z LOW LEVEL THICKNESSES INCREASE AROUND 9 M OVER
THE SAME TIME MONDAY. -SEC
SENSIBLE WEATHER WILL REMAIN WARM AND DRY ACROSS CENTRAL NC AS
SURFACE HIGH ANCHORED OFFSHORE AND A SLOW MOVING LOW PRESSURE SYSTEM
OVER THE SOUTHERN PLAINS MAINTAINS A WARM LOW LEVEL S-SW FLOW OVER
OUR REGION. WLY FLOW BEGINS TO BACK TONIGHT INTO TUESDAY AS A
MID-UPPER LEVEL RIDGE AMPLIFIES NWD OVER THE SE U.S. THIS ADDITIONAL
WARMING ALOFT WILL LEAD TO VERY WARM SFC TEMPS TUESDAY AFTERNOON.
LOW LEVEL THICKNESSES COUPLED WITH A SOUTH-SOUTHWEST BREEZE SUPPORT
AFTERNOON TEMPS NEAR 80 NW TO THE LOWER 80S ELSEWHERE. MIN TEMPS
55-60 TUESDAY NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 230 PM MONDAY...
WEDNESDAY THROUGH THURSDAY:
MID TO UPPER LEVEL RIDGE AXIS IS EXPECTED TO SLOWLY SHIFT OFFSHORE
DURING THIS TIME FRAME... WITH SURFACE HIGH PRESSURE REMAINING
ANCHORED OFFSHORE AND THE NEXT APPROACHING COLD FRONT REMAINING TO
THE WEST OF THE AREA THROUGH THE PERIOD. THIS WILL RESULT IN
CONTINUED ABOVE NORMAL TEMPS... WITH INCREASING CLOUD COVER AND
PRECIP CHANCES BY LATE THURSDAY. STILL EXPECT THE BEST CHANCES FOR
ANY SHOWERS AND OR STORMS TO REMAIN TO THE WEST OF THE AREA THROUGH
THURSDAY AFTERNOON THOUGH... AS THE DEEP TROUGH ALOFT AND ASSOCIATED
COLD FRONT APPROACHES THE AREA FROM THE WEST. HOWEVER... GIVEN
MODELS HAVE TRENDED TO THE FASTER SIDE OF THE GUIDANCE OVER THE PAST
SEVERAL DAYS WITH THIS SYSTEM... WILL GO WITH SLIGHT CHANCE TO LOW
END CHANCE OF SHOWERS AND STORMS FOR LATE THURSDAY AFTERNOON... WITH
THE BEST CHANCE FOR PRECIP EXPECTED OVERNIGHT.
LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PEAK WEDNESDAY AFTERNOON
CLOSE TO 1400 METERS. THIS WILL RESULT IN A WARM AND PARTLY SUNNY
DAY AFTER THE MORNING FOG AND/OR LOW STRATUS BURNS OFF. EXPECT HIGH
TEMPS TO BE IN THE LOWER TO MID 80S... WITH PERHAPS THE WARMEST
TEMPS ACROSS THE NORTHEAST PIEDMONT NEAR THE NC/VA BORDER. LOWS
THURSDAY MORNING WILL HAVE THE SAME FLAVOR... ABOVE NORMAL. EXPECT
LOWS TO BE AROUND 60. HIGHS ON THURSDAY WILL AGAIN BE WARM.
HOWEVER... WE MAY SEE THE STRATUS AND/OR FOG LINGER LONGER AS LOW
MOISTURE IS EXPECTED TO INCREASE FURTHER IN ADVANCE OF THE NEXT
SYSTEM. THUS... WILL GO WITH HIGHS ON THURSDAY IN THE UPPER 70S NW
TO LOWER 80S ELSEWHERE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 205 PM MONDAY...
THURSDAY NIGHT THROUGH FRIDAY NIGHT:
MEDIUM RANGE MODELS ARE COMING IN BETTER AGREEMENT ON THE NEXT
SYSTEM TO AFFECT THE AREA LATE WEEK... TRENDING TO A BIT FASTER
TIMING. THE GFS (12Z/08TH) AND MOST OF ITS ENSEMBLE MEMBERS
CONTINUES TO BE ON THE FAST SIDE OF THE GUIDANCE WHILE THE LATEST
ECMWF (00Z/08TH) AND ITS RESPECTIVE ENSEMBLE MEMBERS A GOOD 6 TO 9
HOURS SLOWER. WPC HAS ELECTED TO GO WITH BEND BETWEEN THE TWO
OPERATIONAL MODELS... KEEPING IN MIND THE GUIDANCE OVER THE PAST FEW
DAYS HAS TRENDED MORE TO A FASTER MORE PROGRESSIVE SOLUTION. THIS
YIELDS A CLOSED LOW INVOF IA/MO LIFTING NORTHEASTWARD INTO THE GREAT
LAKES REGION THURSDAY EVENING INTO FRIDAY... WITH AN ASSOCIATED
PRIMARY SURFACE LOW TRACKING FROM THE OHIO VALLEY INTO THE GREAT
LAKES AND EVENTUALLY NORTHEAST U.S. BY FRIDAY NIGHT... WITH A
TRAILING COLD FRONT AND ACCOMPANYING BAND OF SHOWERS AND STORMS
CROSSING OUR AREA IN A WEST TO EAST FASHION THURSDAY NIGHT INTO
FRIDAY MORNING/EARLY AFTERNOON. THIS IS A BIT FASTER THAN THE
PREVIOUS FORECAST. FOR NOW WILL SPEED UP THE TIMING A BIT... SHOWING
LIKELY POPS FROM LATE THURSDAY/EARLY FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON. HOWEVER... POPS WILL LIKELY NEED TO BE RAISED AND
FOCUSED OVER A SHORTER TIME FRAME WHEN THE TIMING BECOMES MORE
CLEAR. WRT A SEVERE THREAT... GIVEN THE FASTER TIMING THERE APPEARS
TO BE LESS OF A CHANCE OF SEVERE STORMS... THANKS TO THE OVERNIGHT
INTO MAINLY MORNING TIMING... WITH VERY MINIMAL MLCAPE TO WORK WITH.
HOWEVER... GIVEN DEWPOINTS IN THE MID 60S AND A STRONG LOW LEVEL JET
(WITH 925-850 MB WINDS OF AROUND 40 TO 55 KTS) WE COULD STILL SEE A
FEW STRONG TO SEVERE STORMS ACCOMPANY THE BAND OF SHOWERS AND
STORMS... WITH THE MAIN THREAT FROM DAMAGING WIND GUSTS. MOST OF THE
GUIDANCE HAS THE EFFECTIVE COLD FRONT AND BAND OF SHOWERS AND STORMS
TO THE EAST OF THE RAH CWA BY AROUND 18Z FRIDAY... WITH THE MORE
SIGNIFICANT SECONDARY SHOT OF COLDER/DRY AIR NOT ARRIVING UNTIL
FRIDAY NIGHT WHEN THE SURFACE WINDS SWING AROUND FROM SOUTHWESTERLY
TO NORTHWESTERLY. WE DO NOT EXPECT ANY PRECIP WITH THE SECONDARY
COLD FRONT... JUST AN ACCOMPANYING BAND OF CLOUD COVER (WITH GFS
BUFR SOUNDINGS SHOWING A STRONG SUBSIDENCE INVERSION AROUND 775-800
MB).
TEMPERATURES DURING THIS TIME FRAME WILL BE DRIVEN BY THE ACTUAL
TIME OF THE COLD FRONT. FOR NOW WILL SHOW THE INITIAL COLD FRONT
MOVING INTO THE WESTERN PIEDMONT AROUND 12Z FRIDAY WITH THIS FRONT
TO THE EAST OF THE RAH CWA BY EARLY AFTERNOON. HOWEVER... SOUTHWEST
TO WEST-SOUTHWESTERLY FLOW BEHIND THE INITIAL FRONT AND MOSTLY TO
PARTLY SUNNY SKIES RETURNING BEHIND THE FRONT INITIALLY WILL ALLOW
TEMPS TO WARM QUITE NICELY AGAIN INTO THE MID TO UPPER 70S... AFTER
FRIDAY MORNING LOWS IN THE LOWER TO MID 60S. AS MENTIONED ABOVE THE
SECONDARY COLD FRONT IS EXPECTED TO MOVE THROUGH FRIDAY NIGHT...
WHICH WILL YIELD MUCH COOLER/COLDER LOW TEMPS FOR SATURDAY MORNING.
THUS... EXPECT LOWS BY SATURDAY MORNING WILL RANGE FROM THE MID TO
UPPER 40S... WITH PERHAPS A FEW LOWER 50S IN THE FAR SE.
SATURDAY THROUGH MONDAY:
SURFACE HIGH PRESSURE WILL BUILD ACROSS REGION NEXT WEEKEND... WITH
MOSTLY SUNNY/CLEAR SKIES EXPECTED FOR MOST OF THE WEEKEND... WITH
PERHAPS A BIT MORE CLOUD COVER BY LATE SUNDAY. FORECAST UNCERTAINTY
INCREASES SUNDAY NIGHT INTO MONDAY... AS MEDIUM RANGE MODELS
STRUGGLE WITH BOTH A NORTHERN AND SOUTHERN STREAM SYSTEM. FOR NOW
WILL SHOW CLOUD COVER INCREASING DURING THIS TIME... AND INTRODUCE A
SLIGHT CHANCE OF SHOWERS FOR NEXT MONDAY. EXPECT HIGH TEMPS DURING
THIS PERIOD TO BE NEAR TO SLIGHTLY BELOW NORMAL... GENERALLY IN THE
UPPER 60S TO LOWER 70S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 155 AM TUESDAY...
A PERSISTENCE FORECAST...OF LIFR CONDITIONS AT KFAY AND MVFR AT KRWI
IN THE SEVERAL HOURS LEADING UP TO 12-13Z...WILL GENERALLY BE
FOLLOWED UNTIL PROVEN OTHERWISE. SLIGHTLY HIGHER DEWPOINTS THIS
MORNING VERSUS PREVIOUS DAYS DOES SUGGEST A BIT HIGHER PROBABILITY
OF THE STRATUS/FOG LAYER EDGING NORTHWESTWARD TO NEAR KRDU THIS
MORNING...HOWEVER...SO WILL MONITOR OBSERVATIONAL TRENDS AND AMEND
AS NEEDED. AFTER STRATUS AND FOG BURN OFF THROUGH 13-14Z...VFR
CONDITIONS...IN SUBSIDENT RIDGING ALOFT AND ASSOCIATED UNDERLYING
INFLUENCE OF BERMUDA SURFACE HIGH PRESSURE...WILL PREVAIL THROUGH
THE END OF THE 06Z TAF PERIOD. SOUTH SOUTHWESTERLY SURFACE WINDS
AROUND THE BERMUDA HIGH WILL CONTINUE...BUT BE SOMEWHAT WEAKER AND
LESS GUSTY (IF AT ALL) THAN PREVIOUS AFTERNOONS OWING TO A SLIGHTLY
WEAKER MSL PRESSURE GRADIENT.
OUTLOOK: BERMUDA HIGH PRESSURE...CHARACTERIZED BY AREAS OF FOG
AND/OR STRATUS EACH MORNING...MAINLY AT KFAY AND KRWI...WILL RULE
THROUGH WED NIGHT. FORECAST GUIDANCE SUGGESTS THE DEPTH OF THE LOW
LEVEL MOISTURE WILL PEAK THU MORNING...AT WHICH TIME DEEPER STRATUS
AT ALL TERMINALS IS LIKELY...FOLLOWED BY A PERIOD MVFR RANGE
CEILINGS BETWEEN 13-19Z THU AS THE MOIST LAYER RISES INTO A CUMULUS
FIELD. THE APPROACH AND PASSAGE OF A FRONTAL SYSTEM WILL THEN RESULT
IN A GOOD CHANCE OF SHOWERS AND STORMS AND ASSOCIATED SUB-VFR
CONDITIONS CENTERED AROUND LATE THU-FRI.
&&
.CLIMATE...
IF TEMPERATURES REACH 80 EARLY THIS WEEK...IT WILL BE THE FIRST
80-DEGREE MAXIMUM TEMPERATURE AT KGSO SINCE OCTOBER 24...AND AT KRDU
SINCE OCTOBER 25. KFAY REACHED 80 MORE RECENTLY...WITH AN 83-DEGREE
HIGH ON MARCH 16. OVER THE LAST COUPLE OF YEARS...THE FIRST
80-DEGREE DAYS HAVE BEEN...
KGSO...MARCH 18 2011...AND MARCH 14 2012.
BOTH KRDU AND KFAY...FEBRUARY 27 2011...AND MARCH 1 2012.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...SEC/WSS
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...MWS
CLIMATE...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
405 AM CDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 405 CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
COLD HIGH PRESSURE OVER SOUTHERN CANADA WILL BUILD INTO NORTHWEST
NORTH DAKOTA. AS A RESULT...VFR CONDITIONS WILL PREVAIL THROUGH THE
06 UTC TAF PERIOD. THE MAIN AVIATION HAZARD WILL BE GUSTY NORTH
WINDS. ANOTHER WINTER STORM WILL TRACK ACROSS WYOMING AND SOUTH
DAKOTA TUESDAY. THIS WILL ALSO BRING SNOW TO THE FAR SOUTH
TUESDAY...BUT SHOULD REMAIN SOUTH OF THE KDIK-KBIS-KJMS TERMINALS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM...RK
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS MIAMI FL
924 AM EDT TUE APR 9 2013
.UPDATE...
ALREADY MADE SOME ADJUSTMENTS TO THE MORNING UPDATES BASED ON
CURRENT TRENDS. MOST OF THAT WAS JUST TO CHANGE MOSTLY CLOUDY
WORDING TO PARTLY SUNNY. THERE HAVE BEEN ISOLATED SMALL SHOWERS
MOVING OFF THE ATLANTIC IN THE LOW LEVEL SOUTHEASTERLY FLOW. A
STRONG SUBSIDENCE CAP REMAINS IN PLACE AS DEPICTED FROM THE 12Z
MFL SOUNDING SO ANY ADDITIONAL ACTIVITY WILL CONTINUE LOW TOPPED
AND ISOLATED. MARINE ZONES ALSO LOOK TO BE IN GOOD SHAPE.
KOB
&&
.PREV DISCUSSION... /ISSUED 716 AM EDT TUE APR 9 2013/
AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD. GENERALLY
LIGHT EASTERLY FLOW IS EXPECTED AT ALL SITES THROUGH THE MORNING
BEFORE INCREASING BY AFTERNOON. THERE ARE A FEW SHOWERS SPREADING
ASHORE THIS MORNING JUST SOUTH OF THE PBI TERMINAL. THE LATEST
MODEL GUIDANCE INDICATES THIS LIGHT ACTIVITY CONTINUING THROUGH
THE EARLY MORNING HOURS. KAPF SHOULD SEE A GULF BREEZE DEVELOP BY
MID AFTERNOON.
PREV DISCUSSION... /ISSUED 402 AM EDT TUE APR 9 2013/
DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
716 AM EDT TUE APR 9 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD. GENERALLY
LIGHT EASTERLY FLOW IS EXPECTED AT ALL SITES THROUGH THE MORNING
BEFORE INCREASING BY AFTERNOON. THERE ARE A FEW SHOWERS SPREADING
ASHORE THIS MORNING JUST SOUTH OF THE PBI TERMINAL. THE LATEST
MODEL GUIDANCE INDICATES THIS LIGHT ACTIVITY CONTINUING THROUGH
THE EARLY MORNING HOURS. KAPF SHOULD SEE A GULF BREEZE DEVELOP BY
MID AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 402 AM EDT TUE APR 9 2013/
DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
648 AM CDT TUE APR 9 2013
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 231 AM CDT TUE APR 9
2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 645 AM CDT TUE APR 9 2013
LOW LEVEL STRATUS WILL CONTINUE TO DEVELOP ALONG AND BEHIND A
STRONG COLD FRONT PUSHING SOUTHEAST ACROSS CENTRAL AND SOUTHWEST
KANSAS EARLY THIS MORNING. PRIMARILY MVFR CIGS WILL PREVAIL AT
ALL TAF SITES THROUGH THIS AFTERNOON WITH BRIEF PERIODS OF IFR
CIGS POSSIBLE EARLY THIS MORNING. LIGHT SNOW WILL THEN BE POSSIBLE
LATE THIS AFTERNOON AND EVENING AS MUCH COLDER AIR SURGES SOUTH
INTO WESTERN KANSAS. STRONG NORTH WINDS WILL DEVELOP BEHIND THE
FRONT AS IT PUSHES THROUGH EARLY THIS MORNING. WIND SPEEDS MAY
REACH UPWARDS OF 30 TO 40KT WITH GUSTS UP TO 45KT INITIALLY BEHIND
THE FRONT. THE NORTH WINDS WILL GRADUALLY SUBSIDE TO AROUND 20 TO
35KT THIS AFTERNOON, THEN CONTINUE TO SLOWLY DECREASE IN SPEED
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 57 19 36 23 / 30 30 10 0
GCK 45 17 34 23 / 30 30 0 0
EHA 40 17 37 24 / 20 20 0 0
LBL 48 18 36 24 / 20 20 0 0
HYS 49 19 36 24 / 40 50 10 0
P28 70 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
610 AM CDT TUE APR 9 2013
...UPDATE TO LONG TERM...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 57 19 36 23 / 30 30 10 0
GCK 43 17 34 23 / 30 30 0 0
EHA 38 17 37 24 / 20 20 0 0
LBL 46 18 36 24 / 20 20 0 0
HYS 49 19 36 24 / 40 50 10 0
P28 70 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
756 AM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP CUTOFF
OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 741 AM EDT TUE APR 9 2013
EXPECT LIFR/VLIFR CONDITIONS TO LIFT TO MVFR BY LATE MORNING WITH
WEAK DIURNAL HEATING AND DRIER AIR WORKING IN FROM THE NORTH.
CONDITIONS SHOULD IMPROVE TO VFR AT KCMX BY LATE AFTERNOON IN
DOWNSLOPE NE FLOW THERE. NE FLOW WILL LIKELY KEEP MVFR CONDITIONS
GOING TONIGHT OVER KIWD AND KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND 25
KT TUE INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT BEFORE DIMINISHING BACK TO 25 KT ON FRIDAY. WINDS ARE
EXPECTED TO DIMINISH BLO 20 KTS FRI NIGHT INTO SAT AND HIGH PRES
BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
724 AM CDT TUE APR 9 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECAST SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 724 CDT TUE APR 9 2013
PRECIPITATION BEGINNING TO SPREAD NORTH TOWARD MPX TERMINALS AS
PROLONGED PRECIPITATION EVENT THAT WILL LAST THROUGH THURSDAY IS
STARTING TO GET GOING. SEEING AN INTERESTING BATTLE BETWEEN MOIST
AIR SOUTH AND DRY AIR NORTH...WITH VFR CONDS SEEN AT AXN AND VERY
CLOSE TO STC. THIS DRY AIR HAS HELPED HOLD UP ADVANCEMENT OF IFR
CIGS...BUT AS MORE WIDESPREAD PRECIP OVERSPREADS THE AREA...CIGS
SHOULD QUICKLY FALL INTO THE IFR RANGE THIS MORNING AND MAY VERY
WELL STAY FIRMLY PLANTED THERE THROUGH MUCH OF THURSDAY. TIMED
INITIAL WAVE OF PRECIP ON THE HRRR...BUT KEPT IT OUT OF AXN PER
THE GFS WITH DRY AIR DOING A SIGNIFICANT NUMBER TO MOISTURE
PROFILES ACROSS CENTRAL MN. WILL SEE SEVERAL WAVES OF PRECIP OVER
THE NEXT FEW DAYS AND FOLLOWED THE IDEA OF THE RAP AND NAM AND
OTHER HIGH-RES MODELS WITH A BRIEF LULL IN PRECIP THIS EVENING
BEFORE ANOTHER WAVE OF PRECIP MOVES IN THIS TONIGHT. THOUGH THE
ENTIRE DAY WILL NOT BE FILLED WITH PRECIP...DRY PERIODS SHOULD BE
FAR OUTNUMBERED BY WET PERIODS. P-TYPE ALSO TOUGH AS WELL...WITH
SIGNIFICANT DISAGREEMENTS BETWEEN THE RAP AND NAM IN TERMS OF
P-TYPE. BASED ON CURRENT CONDITIONS...THE RAP LOOKS TO BE RUNNING
WARM...SO FOLLOWED THE NAM FOR P-TYPE. STILL LOOKS GOOD FOR A
PROLONGED PERIOD OF MIXED PRECIP OUTSIDE OF AXN...AND BASED ON
DEPTH OF SUB-FREEZING LAYER...PREDOMINATE P-TYPE LOOKS TO BE SLEET
UNTIL THE WARM NOSE AROUND 6K FT ABOVE THE GROUND CAN BE BEAT
BACK. FOR AS CHAOTIC AS THE WX/CIG/VIS WILL BE...WINDS WILL FAIRLY
UNIFORM THIS PERIOD OUT BETWEEN 010 AND 040.
KMSP...FOR CIGS...WITH DRIER NE WINDS...MAY SEE CIGS GO ABOVE
1700 FT UNTIL STEADIER RAIN ARRIVES AROUND 14Z. AFTER THAT...WILL
SPEND A LONG DURATION OF TIME WITH CIGS UNDER 1700 FT. BASED ON
THE RAP/NAM...EXPECT A BREAK IN THE STEADY PRECIP BETWEEN ABOUT
21Z AND 6Z...BEFORE ANOTHER BATCH OF MORE PERSISTENT PRECIP MOVES
IN. CONFIDENCE HIGH IN A P-TYPE OF RAIN TODAY. A TRANSITION TO
SLEET IS EXPECTED THIS EVENING BETWEEN 3 AND 6Z...AND BASED ON
CURRENT NAM BUFKIT SOUNDINGS...MSP MAY SPEND CLOSE TO THE NEXT 24
HOURS WITH SLEET OR A SLEET/RAIN MIX BEFORE FINALLY SWITCHING TO
SNOW WEDNESDAY NIGHT.
/OUTLOOK FOR KMSP/
WED...IFR WITH SN. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 15G12 KTS.
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
942 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 931 AM CDT TUE APR 9 2013
AT 9 AM CDT...COLD SURFACE HIGH REMAINS ACROSS SASKATCHEWAN INTO
MONTANA. LARGE EARL SPRING STORM CONTINUES TO DEVELOP FROM THE
ROCKIES INTO THE CENTRAL PLAINS. ALL BUT THE VERY SOUTHERN TIER
OF COUNTIES WILL SEE SOME HIGH CLOUDINESS. THE SOUTHERN COUNTIES
WILL SEE CONTINUOUS LIGHT SNOW OR FLURRIES. ADDED FLURRIES TO A
LARGER PORTION OF THE SOUTHWEST FOR THE MORNING HOURS..AS BAKER
MONTANA AND BEACH. ARE REPORTING SOME FLURRIES THIS MORNING.
TEMPERATURES LOOK OK SO FAR.
UPDATE ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 940 AM CDT TUE APR 9 2013
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE REGION TUESDAY.
THERE ARE WIDESPREAD HUIGH CLOUDS...SOME THINNING NORTH. VFR
CONDITIONS WILL PREVAIL TODAY AS DRY NORTHERLY FLOW OUT OF THE
HIGH SHOULD KEEP LIGHT SNOW CONFINED SOUTH OF KDIK-KBIS-KJMS.
ALTHOUGH SOME FLURRIES ARE POSSIBLE AT KDIK THROUGH 17Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...RK
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
937 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 935 AM CDT TUE APR 9 2013
FORECAST CHALLENGE FOR UPDATES TODAY WILL BE SNOW CHANCES ALONG
ND/SD/MN BORDER AREA AND TEMPERATURES.
SO FAR DRIER AIR WINNING OUT WITH NORTHERN EDGE OF SNOW BAND WITH
FIRST WAVE FROM BIG STORM SOUTH OF OUR FA AND THE RED BASIN.
EXPECT THESE TRENDS TO CONTINUE TODAY AND HAVE DOUBTS WHETHER ANY
OF THE FAR SOUTHERN FA WILL GET ANY SNOW. DID NOT COMPLETELY PULL
POPS BUT LOWERED TO LOW CHANCES ALONG BORDER AREA TO BE SAFE. VERY
COLD START TODAY HOWEVER WITH COLD ADVECTION OVER AND SOME
FILTERED EARLY APRIL SOLAR TEMPERATURES SHOULD RESPOND. DID NOT
MAKE ANY CHANGES WITH TEMPERATURES BUT WILL MONITOR FOR NEXT
UPDATE. ONLY OTHER CHANGES WERE ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM CDT TUE APR 9 2013
EXPECT VFR CONDITIONS IN ALL AREAS AS DRY NORTHERLY LOW LEVEL FLOW
CONTINUES TO SPREAD A DRY AIRMASS INTO THE REGION. SNOW WILL
REMAIN SOUTH OF ALL TAF SITES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
745 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 720 AM CDT TUE APR 9 2013
MAINLY VFR CONDITIONS TODAY AS DRY NORTHERLY FLOW SHOULD KEEP
LIGHT SNOW CONFINED SOUTH OF KDIK-KBIS-KJMS. MVFR FOG IS POSSIBLE OVERNIGHT
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RK
SHORT TERM...LTH
LONG TERM...RK
AVIATION...RK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
647 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM CDT TUE APR 9 2013
EXPECT VFR CONDITIONS IN ALL AREAS AS DRY NORTHERLY LOW LEVEL FLOW
CONTINUES TO SPREAD A DRY AIRMASS INTO THE REGION. SNOW WILL
REMAIN SOUTH OF ALL TAF SITES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1004 AM CDT TUE APR 9 2013
.UPDATE...
THE COLD FRONT HAS PASSED THROUGH FRIONA...DIMMITT...AND HAPPY
ALREADY QUITE A BIT AHEAD OF SCHEDULE. SHORT TERM SURFACE PRESSURE
RISES HAVE WEAKENED BUT THE FRONT WAS CONTINUING TO ADVANCE ON
LARGER SCALE PUSHES. WE HAVE ACCEPTED THE LATEST RAP RUN FOR NOW
AND UPDATED FOR THE FRONT TO WORK THROUGH MOST OF THE NORTHERN
AREA BEFORE STALLING AROUND MIDDAY. TEMPERATURES LOWERED ACROSS
NORTHERN ZONES AND WARMED SLIGHTLY SOME SOUTHERN AREAS. THE FRONT
MAY BE ABLE TO CATCH UP TO THE MOISTURE LYING OVER THE NORTHERN
ROLLING PLAINS AND GIVE A VALID LOW CHANCE FOR THUNDER. WE WILL
STUDY FURTHER FOR SEVERE CHANCES AS WELL. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 623 AM CDT TUE APR 9 2013/
AVIATION...
MVFR CIGS DEVELOPING IN MOIST AIR THAT HAS MOVED BACK INTO THE
FCST AREA WILL PERSIST UNTIL LOW LEVEL WINDS BEGIN TO VEER TO THE
SW AND INCREASE IN SPEED. THAT IS LIKELY TO OCCUR BY 14Z AT KLBB
AND 17Z AT KCDS. AFTERWARDS...GUSTY SW WINDS EXPECTED THROUGH THE
DAY FOLLOWED BY GUSTY NORTH WINDS BEHIND A STRONG COLD FRONT THAT
WILL MOVE THROUGH THE FCST AREA THIS EVENING. POTENTIAL FOR SOME
LIGHT SHOWERS OVERNIGHT WITH THE APPROACH OF AN UPPER LEVEL
DISTURBANCE FAVORS KCDS OVER KLBB.
PREV DISCUSSION... /ISSUED 319 AM CDT TUE APR 9 2013/
SHORT TERM...
RATHER DYNAMIC PATTERN SETTING UP FOR THE NEXT 24 HOURS AS A STRONG
UPPER LOW EJECTS FROM THE 4-CORNERS TO THE CNTL PLAINS WHILE THE
PARENT TROUGH MOVES FROM WEST TO EAST TOWARD THE FCST AREA.
INITIALLY A MID LEVEL JET WILL PUNCH ACROSS THE AREA AS IT ROTATES
NEWD WITH THE UPPER LOW. PROGGED MAGNITUDE OF THIS JET HAS WEAKENED
RELATIVE TO RECENT MODEL RUNS WITH 500 MB SPEEDS OF AROUND 90 KTS
AND 700 MB ABOUT HALF THAT. MIXING WILL BE FAIRLY EFFICIENT DESPITE
COOLER TEMPERATURES THAN THE LAST FEW DAYS COURTESY OF LOWERING
HEIGHTS AND THICKNESSES WITH THE ADVANCING UPPER TROUGH. THIS SHOULD
RESULT IN WINDS MOSTLY IN A RANGE OF 20 TO 30 MPH...PERIODICALLY
SLIGHTLY STRONGER UP ON THE CAPROCK...ATTM NOT EXPECTED TO BE QUITE
STRONG ENOUGH TO JUSTIFY A WIND ADVISORY. THIS MID LEVEL JET MAX
WILL HELP QUICKLY MIX THE DRYLINE EWD THROUGH THE FCST AREA WITH LOW
DEW POINT AIR MOVING IN BEHIND IT AND EFFECTIVELY KILLING ANY PRECIP
CHANCES DURING THE AFTN.
THAT LOOKS TO CHANGE OVERNIGHT AS THE UPPER TROUGH CONTINUES TO
ADVANCE TOWARD THE AREA. MID LEVEL LIFT AND MOISTURE ASSOCIATED WITH
THE TROUGH LIKELY SUFFICIENT TO PRODUCE SOME ELEVATED SHOWERS ACROSS
MAINLY THE NRN HALF OF THE FCST AREA WHERE THAT COMBINATION WILL BE
GREATEST. STILL DO NOT EXPECT ANYTHING MORE THAN A SCATTERED NATURE
TO THE SHOWERS AND 30 TO 40 PCT POPS THERE LOOK REASONABLE. FCST
FURTHER COMPLICATED BY A STRONG COLD FRONT THAT WILL MOVE QUICKLY
THROUGH THE FCST AREA DURING THE EVENING HOURS. THIS FRONT WILL
USHER IN VERY COLD AIR THE STRENGTH OF WHICH IS INDICATED BY
TEMPERATURES IN THE TEENS AND 20S ACROSS SERN WYOMING AND NERN
COLORADO PENETRATING SWD DOWN THE LEE OF THE FRONT RANGE. THAT FRONT
IS JUST SOUTH OF A TRINIDAD COLO TO SPRINGFIELD COLO TO COLBY KS
LINE AT 08Z. THIS IS JUST A BIT AHEAD OF WRF-NAM POSITIONING. THE
FRONT WILL MOVE INTO THE TEXAS PANHANDLE THIS MORNING WHERE IT
SHOULD STALL IN THE FACE OF WARM TEMPS AND SW WINDS...BUT THEN
QUICKLY ACCELERATE SWD LATE THIS AFTN OR EARLY THIS EVENING. COLD AIR
THAT COMES IN BEHIND THE FRONT MAY BE COLD ENOUGH TO PRODUCE SOME
FROZEN PRECIP BEFORE PRECIP COMES TO AN END TONIGHT...AND WILL
MAINTAIN THAT WORDING IN THE FCST WITH ONLY MINOR ADJUSTMENTS TO
AREAL EXTENT. PRESSURE RISES BEHIND THE FRONT LIKELY TO BE FAIRLY
STRONG WITH SOME POTENTIAL FOR WIND ADVISORY SPEEDS FOR A TIME
OVERNIGHT.
LONG TERM...
PER THE NAM...GFS AND CMC SOLUTIONS...THE MEAN TROUGH OF THE BROAD UA
LOW ACROSS THE CENTRAL PLAINS WILL CONTINUE TO SWING EAST ACROSS THE
ROLLING PLAINS TOMORROW MORNING...WHILST THE BEST PRECIP WILL
SHIFT EAST OF THE CWA THUS COINCIDING WITH BEST LARGE SCALE ASCENT.
THE ECMWF IS A BIT OF AN OUTLIER AS IT IS SLIGHTLY SLOWER THAN THE
OTHERS...AND THUS EXHIBITING PRECIP LINGERING THROUGH TOMORROW
AFTN. WILL LEAN TOWARDS THE FORMER SOLUTIONS ATTM...GIVEN BETTER
CONSISTENCY. A 1020+ MB SFC RIDGE WELL NORTH OF THE REGION WILL BE
THE DRIVING FORCE BEHIND THE COLD FRONT...SET TO INTRUDE THE
REGION TONIGHT AND BE LOCATED ACROSS THE PERMIAN BASIN BY TOMORROW
MORNING. INITIAL PRESSURE RISES OF 12 MB/3 HR WILL HAVE RELAXED
SUBSTANTIAL AT THE START OF THE EXTENDED PERIOD...HOWEVER 850 MB
TEMPS HOVERING NEAR THE FREEZING MARK DURING THE DAY TOMORROW
SUGGEST TEMPS IN THE 40S AND 50S...OR SOME 15-20 DEGREES BELOW
NORM.
THE AFOREMENTIONED SFC RIDGE WILL SHIFT SOUTH TO ACROSS THE CWA
TOMORROW NIGHT THUS PROMOTING LIGHT AND VARIABLE WINDS...IN ADDITION
TO MAINTAINING 850 MB TEMPS NEAR/SLIGHTLY BELOW FREEZING. IT IS NO
WONDER MOS GUIDANCE HINTS AT OVERNIGHT TEMPS RIGHT AT OR BELOW
FREEZING ACROSS THE ENTIRE CWA. SINCE WE ARE JUST ENTERING THE
GROWING SEASON THIS OF COURSE RAISES CONCERN. WILL ADD STRONG
WORDING TO THE HAZARDOUS WEATHER OUTLOOK ATTM...HOWEVER A
FREEZE WATCH/WARNING MAY BE REQUIRED AND WILL LET LATER SHIFTS
ANALYZE FUTURE MODEL RUNS TO SEE IF THIS IS INDEED WARRANTED.
BROAD CYCLONIC FLOW ALOFT WILL BECOME NWRLY BY THURSDAY...WHILST SFC
RIDGING TRANSLATES AWAY FROM THE REGION...AND THE DEVELOPMENT OF SFC
LEE TROUGHING ENCOURAGES A RETURN TO SRLY FLOW AND THUS WARMER
TEMPS /UPPER 60S TO LOW TO MID 70S BY FRIDAY/. THEREAFTER...A FRONT IS
PROGGED TO MOVE ACROSS MOST OF THE CWA FRIDAY NIGHT /PRODUCING THE
DEVELOPMENT OF MID-LEVEL CLOUDINESS/...AHEAD OF AN EMBEDDED
DISTURBANCE IN THE FLOW ALOFT...SET TO MOVE ACROSS THE REGION
FRIDAY NIGHT. MODELS CONTINUE TO SHOW LIGHT QPF SIGNALS MAINLY ACROSS
THE NERN ZONES DURING THE SAID TIME PERIOD...AND HAVE ELECTED TO
INCREASE POPS TO 14 PERCENT...JUST BELOW MENTIONABLE LEVELS ATTM.
SFC LEE CYCLOGENESIS WILL RESUME FOR THE WEEKEND THROUGH EARLY NEXT
WEEK...LEADING TOWARDS TEMPS WARMING INTO THE 70S AND 80S. AS
SUCH...A DRYLINE WILL SHARPEN AND LINGER ACROSS THE FA. LONG TERM
SOLUTIONS SHOW RATHER PROGRESSIVE FLOW ACROSS THE NRN CONUS...AND
ONE OF THOSE DISTURBANCES WILL SEND A BACKDOOR COLD FRONT TOWARDS
THE SERN TEXAS PANHANDLE MONDAY. COULD SEE PRECIP DEVELOP ALONG THE
DRYLINE AND COLD FRONTAL BOUNDARY INTERSECTION ACROSS THE ROLLING
PLAINS...BUT HAVE KEPT POPS SILENT AND WILL AWAIT TO SEE IF THIS
PATTERN AND ASSOCIATED MESO-SCALE FEATURES ARE CONSISTENT FROM RUN TO
RUN.
FIRE WEATHER...
MARGINALLY CRITICAL CONDITIONS POSSIBLE FOR A TIME THIS AFTERNOON
WITH THE MAIN LIMITING FACTOR BEING RELATIVE HUMIDITY. HAVE LOWERED
FCST RH A LITTLE THIS MORNING WITH EXPECTATION OF SLIGHTLY WARMER
TEMPS THAN PREVIOUSLY EXPECTED. THAT WILL BRING MINIMUM RH VALUES
NEAR 15 PCT FOR MUCH OF THE AREA WHILE WINDS SHOULD FAIRLY EASILY
EXCEED 20 MPH AT THE 20-FOOT LEVEL. SOME QUESTION TOO OF HOW MUCH
THOSE TWO WILL OVERLAP WITH POSSIBILITY OF THE WIND SPEEDS MAXING
OUT A LITTLE AHEAD OF THE RH BOTTOM. SHOULD SEE SOME PERIODS OF
CRITICAL CONDITIONS AS RH FLIRTS WITH THE 15 PCT CRITERIA...BUT
PRETTY UNCERTAIN WITH RESPECT TO DURATION. GIVEN UNCERTAINTIES AS
WELL AS GOOD RH RECOVERY FOR ALMOST ALL OF THE FCST AREA THIS
MORNING WILL OPT FOR A FIRE DANGER STATEMENT OVER A RED FLAG WARNING
ATTM.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 56 20 48 25 64 / 10 30 0 0 0
TULIA 65 24 49 24 63 / 10 30 10 0 0
PLAINVIEW 70 26 51 25 63 / 10 30 10 0 0
LEVELLAND 74 26 53 27 66 / 10 20 0 0 0
LUBBOCK 76 30 53 27 66 / 0 20 10 0 0
DENVER CITY 75 29 55 27 68 / 10 10 0 0 0
BROWNFIELD 75 30 55 27 67 / 10 10 0 0 0
CHILDRESS 71 33 51 27 65 / 10 40 10 0 0
SPUR 84 35 55 29 66 / 0 20 10 0 0
ASPERMONT 89 37 55 30 66 / 0 20 10 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99
AREA FORECAST DISCUSSION
NWS PUEBLO CO
320 PM MDT TUE APR 9 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT TUE APR 9 2013
UPPER LOW OVER AZ AND UT IS FINALLY LIFTING TO THE NORTHEAST INTO
WESTERN CO AS 120 KT JET LIFTS TO THE NORTHEAST ACROSS CEN/SRN NM.
UPPER LEVEL IMPULSES HAVE BROUGHT ROUNDS OF SNOW TO THE AREA TODAY.
THE FIRST WAVE CAME ACROSS THIS MORNING AND BROUGHT A BRIEF ROUND OF
SNOW TO THE I-25 CORRIDOR...AND BRIEF BLIZZARD
CONDITIONS...ESPECIALLY AT THE KPUB AIRPORT BETWEEN 9 AM AND 11 AM.
THIS WAVE HAS SINCE LIFTED OFF TO THE NORTHEAST OF THE AREA.
HOWEVER...ANOTHER WAVE IS NOW LIFTING TO THE NORTH ACROSS THE I-25
CORRIDOR. NORTH WINDS HAVE DECREASED SOME ACROSS THE PLAINS...BUT
THERE HAVE STILL BEEN SOME INTERMITTENT GUSTS TO AROUND 40 MPH. AS
THE LATE AFTERNOON AND EVENING PROGRESSES...EXPECT THAT THESE WINDS
WILL CONTINUE TO COME DOWN...AND ALTHOUGH THERE WILL STILL BE A
BRIEF WINDOW OF SNOW AND BLOWING SNOW...THINK THAT IMPACTS WON`T BE
AS HIGH AS THE BLIZZARD CONDITIONS WE SAW BRIEFLY EARLIER. THUS
HAVE DOWNGRADED THE BLIZZARD WARNINGS TO WINTER WEATHER ADVISORIES.
SNOWFALL FOR THE SOUTHEAST MOUNTAINS HAS ALSO COME UP SHY...AND WITH
BEST ISENTROPIC UPGLIDE PUSHING OFF TO THE NORTHEAST OF THE AREA
LATE THIS AFTERNOON AND EVENING...THINK THAT THE WINDOW FOR HEAVIER
SNOWFALL AMOUNTS IS CLOSING. STILL THINK A GOOD 4 TO 8 INCHES MAY
BE REALIZED...SO DOWNGRADED THE SOUTHEAST MOUNTAINS TO A WINTER
WEATHER ADVISORY AS WELL. TELLER COUNTY MAY END UP COMING UP SHORT
ON THESE AMOUNTS. ADVISORIES ARE SET TO EXPIRE AROUND 6 PM FOR MOST
AREAS...THOUGH DID HANG ON TO THEM A LITTLE LONGER FOR THE
WETS...NORTHERN SANGRES...AND THE UPPER ARKANSAS RIVER VALLEY OF
FREMONT AND CHAFFEE COUNTIES WHERE THE RUC13 CONTINUES TO KEEP SOME
SNOW GOING THROUGH THEN.
AREAS DOING THE BEST FROM THIS STORM APPEAR TO BE ACROSS THE
SOUTHWEST AND CENTRAL MOUNTAINS WHERE SNOW SHOWERS HAVE BECOME MORE
CONVECTIVE IN NATURE THIS AFTERNOON. KALS HAS SEEN BRIEFLY POOR VIS IN HEAVY
SNOW FROM A THUNDER SNOW SHOWER EARLIER THIS AFTERNOON. IN
FACT...IN AND AROUND NATHROP AND SALIDA HAVE PICKED UP ON THE
ORDER OF 5 TO 6.5 INCHES OF SNOW. THIS IS WHERE THE UPPER LEVEL
DIFFLUENCE HAS BEEN BEST...ESPECIALLY THIS MORNING. HAVE EXTENDED
THE ADVISORIES AND WARNINGS ACROSS THE SOUTHWEST AND CENTRAL
MOUNTAINS THROUGH 03Z TO ACCOUNT FOR SOME RESIDUAL LIFT AND
INSTABILITY THROUGH THE EVENING. AFTER 03Z...THINK SNOWFALL RATES
WILL DECREASE QUICKLY. OVERALL ANOTHER 1 TO 4 INCHES CAN BE
EXPECTED ACROSS THE HIGHER ELEVATIONS THROUGH THAT TIME.
FOR TONIGHT...COLD OVERNIGHT LOWS EXPECTED...THOUGH RESIDUAL CLOUD
COVER WILL KEEP THEM FROM PLUMMETING AS FAR AS THEY POTENTIALLY
COULD GIVEN THE COLD AIRMASS IN PLACE. LOWS SHOULD DROP INTO THE
TEENS FOR MOST AREAS...WITH SINGLE DIGITS ACROSS SOME OF THE MOUNTAIN
AREAS.
UPPER LOW WILL SLOWLY LIFT OFF TO THE NORTHEAST ON WEDNESDAY...THOUGH WITH
RESIDUAL MOISTURE AND INSTABILITY OVER THE REGION...HAVE MAINTAINED
SOME ISOLATED TO SCATTERED SNOW SHOWERS...MAINLY OVER AND NEAR THE
MOUNTAINS. TEMPERATURES WILL REMAIN BELOW NORMAL...WITH HIGHS ONLY
TOPPING OUT IN THE 30S TO LOWER 40S FOR THE LOWER ELEVATIONS WITH
20S AND 30S FOR THE MOUNTAIN AREAS. -KT
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 PM MDT TUE APR 9 2013
WEDNESDAY NIGHT THROUGH FRIDAY...ONE UPPER LOW PRES SYSTEM IS
FORECAST TO BE EXITING THE REGION WED NIGHT...WITH ONLY A BRIEF
BREAK IN PCPN FOR THE HIGHER TERRAIN BEFORE ANOTHER UPPER
DISTURBANCE ROLLS IN. THE NEXT WAVE IS EXPECTED TO TRACK ACROSS THE
GREAT BASIN AND N ROCKIES THU THROUGH FRI MORNING...BRINGING
SCATTERED SNOW SHOWERS TO THE MTS THU AND FRI...AND A RAIN SNOW MIX
FOR THE ADJACENT PLAINS THU NIGHT THROUGH FRI MORNING. TEMPS ARE
EXPECTED TO WARM A BIT WITH MAX TEMPS IN THE 50S THU AND FRI...BUT
MIN TEMPS STILL IN THE 20S TO AROUND 30 F BOTH NIGHTS.
SATURDAY AND SUNDAY...THE GFS AND ECMWF MODELS INDICATE THAT A BROAD
LOW PRESSURE AREA WILL GRADUALLY TRACK EAST ALONG THE US CANADA
BORDER OVER THE WEEKEND...PRODUCING BRISK WESTERLY FLOW ACROSS
COLORADO WITH A LINGERING THREAT OF PCPN FOR MAINLY THE NORTHERN
HALF OF THE STATE. THIS WILL LEAK ISOLATED SHOWERS DOWN INTO THE
CENTRAL MTS ON SAT...THEN THE CONTDVD AND PALMER DVD FOR SUN. THE
WESTERLY FLOW SHOULD HELP BOOST MAX TEMPS BOTH DAYS INTO THE 60S TO
NEAR 70 F FOR THE E PLAINS.
MONDAY AND TUESDAY...THE UPPER LOW GATHERS STRENGTH AND DROPS SOUTH
OUT OF THE PAC NW EARLY MON MORNING...THEN SAGS TO THE SW ACROSS THE
GREAT BASIN LATE MON. SW FLOW ALOFT INCREASES ACROSS THE 4 CORNERS
ON MON...DRAWING IN MOISTURE TO THE HIGHER TERRAIN FOR MON AND THEN
SPREADING ACROSS MUCH OF THE FORECAST AREA FOR TUE. EARLY YET O
COURSE...BUT THIS SYSTEM LOOKS TO BE THE STRONGER FEATURE FOR THE
EXTENDED PERIOD. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 320 PM MDT TUE APR 9 2013
ANOTHER ROUND OF SNOW WILL LIFT TO THE NORTH ACROSS THE I-25
CORRIDOR LATE THIS AFTERNOON THROUGH EARLY THIS EVENING. THIS
PRODUCE MVFR TO IFR CONDITIONS AT THE KCOS AND KPUB TAF SITES
THROUGH THE LATE AFTERNOON AND EVENING...WITH CIGS RISING INTO THE
MVFR CATEGORY AS DRYING MOVES IN BEHIND. GUSTY NORTH WINDS FROM 20
TO 35 KTS WILL GRADUALLY DECREASE THROUGH THE EVENING...AND ALTHOUGH
THERE WILL STILL BE A PERIOD OF FALLING/BLOWING SNOW WITH THIS
BAND...THINK THAT ANY ADDITIONAL ACCUMULATIONS WILL REMAIN AROUND AN
INCH OR LESS FOR BOTH TERMINALS. SNOW SHOULD COME TO AN END FOR BOTH
TAF SITES BY 03Z...WITH MVFR CIGS PERSISTING THROUGH THE NIGHT. KALS
WILL SEE THE BEST CHANCE FOR SNOW FROM NOW THROUGH 03Z...WITH
PERIODIC IFR CIGS/VIS IN SNSH. MVFR CIGS WILL PERSIST THROUGH THE
NIGHT.
VFR TO MVFR CIGS WILL CONTINUE ACROSS THE REGION THROUGH
WEDNESDAY...WITH INSTABILITY SNOW SHOWERS ACROSS THE MOUNTAINS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR
COZ061>063-065-067-072-073-076>080-089-093>096.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ059-
064-069>071-074-075-081>088.
WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ058-060-
066-068.
&&
$$
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1229 PM CDT TUE APR 9 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 231 AM CDT TUE APR 9
2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1229 PM CDT TUE APR 9 2013
GUSTY NORTH WINDS AT AROUND 25 TO 35 KNOTS WILL CONTINUE THROUGH
THE AFTERNOON HOURS. THE WINDS SHOULD DIMINISH SOMEWHAT WITH
SUNSET BUT WILL CONTINUE TO BE GUSTY. LIGHT FREEZING DRIZZLE WILL
BE POSSIBLE AT THE TAF SITES THIS AFTERNOON. AFTER 00Z, FREEZING
RAIN WILL BE POSSIBLE WHICH SHOULD BE CHANGING OVER TO LIGHT SNOW
LATER TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 49 19 36 23 / 30 30 10 0
GCK 36 17 34 23 / 30 30 0 0
EHA 32 17 37 24 / 30 20 0 0
LBL 39 18 36 24 / 20 20 0 0
HYS 45 19 36 24 / 40 50 10 0
P28 67 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
646 PM EDT TUE APR 9 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOWS OVER
HUDSON BAY AND THE THE CENTRAL ROCKIES AND A RIDGE OVER THE SE CONUS
LEAVING CONFLUENT WRLY FLOW THROUGH NRN MN INTO NRN LAKE SUPERIOR.
AT THE SFC... A TROUGH STRETCHED THROUGH CNTRL KS INTO SRN IA FROM
LOW PRES OVER WRN TX. A WARM FRONT EXTENDED FROM SRN IA AND NRN IL
INTO NRN OH. NRLY FLOW HAD INCREASED THROUGH UPPER MI BEHIND A COLD
FRONT AS HIGH PRES OVER SASK BUILDS TOWARD NRN ONTARIO.
A LARGE AREA OF RAIN FROM CNTRL WI INTO FAR SRN UPPER MI WAS
SUPPORTED BY UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 150KT
250-300 MB JET STREAK OVER NRN ONTARIO AND LOWER LEVEL RESPONSE WITH
300K-305K (750-650 MB) ISENTROPIC ASCENT NORTH OF THE WARM FRONT.
THE PCPN AMOUNTS HAVE BEEN LIMITED AS AN MCS THROUGH SRN WI HAS
REDUCED MOISTURE INFLOW TO THE NORTH.
TONIGHT INTO WED...
ALTHOUGH THE FIRST BATCH OF PCPN OVER SRN UPPER MI
WILL MOVE OFF TO THE EAST THIS EVENING ANOTHER WEAK SHORTWAVE
EMERGING FROM THE PLAINS COMBINED ANOTHER INCREASE IN UPPER LEVEL
JET RIGHT ENTRANCE UPPER LEVEL DIV AND CONTINUED ISENTROPIC ASCENT
OVER THE REGION IS EXPECTED TO BRING ANOTHER ROUND OF PCPN
OVERNIGHT INTO WED MORNING. THERE IS SOME UNCERTAINTY WITH THE
TIMING AS THE GFS MOVES THE PCPN OUT MORE QUICKLY THAN THE
NAM/GEM/ECMWF.
SINCE THE THERE WAS PROMINENT LOWER LEVEL (285-290K ISENTROPIC
DESCENT) WITH DRIER AIR FLOWING TOWARD THE REGION HIGHER POPS WERE
LIMITED TO THE FAR SOUTH WITH A SHARP GRADIENT TO THE NORTH. NAM
TEMP PROFILE WITH A 1C-2C LAYER BETWEEN 800-700 MB SUGGESTS THAT
SLEET WILL BE THE PREDOMINANT PCPN TYPE IN THE AREA OF GREATEST QPF
WITH MAINLY SN/PL ON THE NRN EDGE. SOME FZRA MAY ALSO BE POSSIBLE
BUT SHOULD BE LESS SIGNIFICANT GIVEN THE SMALL WARM AREA ON THE FCST
SOUNDINGS.
CLOUDS/WIND SHOULD REDUCE DIURNAL TEMP RANGE. TEMPS ARE EXPECTED TO
REMAIN JUST AT OR BELOW FREEZING OVER THE SOUTH AND IN THE UPPER 20S
TO AROUND 30 OVER THE NORTH TONIGHT WITH HIGHS WED ONLY IN THE MID
30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
MUCH OF THE ATTENTION OF THIS FORECAST WILL BE ON THE UPCOMING
WINTER WEATHER EXPECTED THURSDAY THROUGH THE START OF THE WEEKEND.
FOR HYDROLOGICAL CONCERNS...THERE IS STILL 10-30 PLUS INCHES OF SNOW
STILL ON THE GROUND OVER THE MUCH OF THE HIGHER TERRAIN OF NORTHERN
UPPER MICHIGAN /SEE THE LATEST RTP OR NOHRSC SNOW ANALYSIS PAGE/.
ALTHOUGH WE WILL BE ADDING PRECIPITATION ON TOP OF THE SNOWPACK...A
QUICK MELT IS NOT FORESEEN AT THIS TIME...WITH TEMPERATURES FORECAST
TO REMAIN BELOW NORMAL THROUGH AT LEAST THE WEEKEND.
WEDNESDAY NIGHT WILL START OFF WITH STRONG HIGH PRESSURE SET UP
ACROSS ONTARIO...INFLUENCING MUCH OF OUR WEATHER INITIALLY WITH DRY
ENE FLOW FUNNELING IN FROM EASTERN ONTARIO. WENT AHEAD AND SLOWED
DOWN THE APPROACHING MOISTURE FROM THE SOUTHWEST ONCE AGAIN.
SOUTH CENTRAL UPPER MICHIGAN WILL CONTINUE TO BE RIGHT ALONG THE
NORTHERN PRECIPITATION SHIELD THROUGH MID MORNING THURSDAY. BY 18Z
THURSDAY THE SFC LOW SHOULD BE SET UP ACROSS SOUTHERN
WISCONSIN/NORTHERN ILLINOIS AND INDIANA.
AT THIS POINT THE BEST OPTION LOOKS TO FOLLOW A BLEND BETWEEN THE
12Z ECMWF AND NAM...WITH LESS INCLUSION OF THE QUICKER GFS.
CONFIDENCE IS INCREASING ON THE IDEA OF STRONG STRONG EAST TO
NORTHEASTERLY WINDS WEDNESDAY NIGHT THROUGH THURSDAY
EVENING...PARTICULARLY NEAR ESC AND MNM AND WESTERN LAKE SUPERIOR.
THE GFS...GIVEN THE WEAKER AND SFC LOW CENTERED FARTHER TO THE EAST
IS UNDERSTANDABLY LIGHTER WITH THE WIND FORECAST...BUT WILL HAS
30-35KT WINDS OVER FAR SW LAKE SUPERIOR AND OUR EASTERN LAKE
MICHIGAN ZONES.
SNOWFALL AMOUNT WITH THIS SYSTEM CONTINUE TO BE A CONCERN.
HOWEVER...WITH AS MUCH MODEL SPREAD STILL SHOWN...WILL NOT ISSUE ANY
SNOW HEADLINES...BUT CONTINUE TO MENTION THE POTENTIAL IN THE HWO.
THE 12Z ECMWF HAS BECOME MORE PROGRESSIVE...EJECTING THE 500MB LOW
TO EASTERN ONTARIO SATURDAY MORNING...OR 6-12 HOURS FASTER THAN THE
09/00Z RUN. THIS IS STILL QUITE A BIT SLOWER THAN THE MERGING GFS
SOLUTION...WITH THE LOW MOVING AS CLOSE AS CENTRAL LOWER
MICHIGAN...WHILE THE NAM/GFS TRACK IT ACROSS UPPER MICHIGAN. THE
09/12Z CANADIAN INITIALLY LOOKS TO BE A GOOD COMPROMISE BETWEEN THE
2 CAMPS...BUT IS MUCH WEAKER WITH LESS THAN A QUARTER INCH OF LIQUID
ACROSS THE MUCH OF THE CWA. THE GFS DOES NOT DO MUCH BETTER...WITH A
GOOD DRY LAYER SHOWING UP ON THE FCST SOUNDINGS BETWEEN 900 AND
700MB. SNOWFALL AMOUNTS COULD VARY SIGNIFICANTLY...BUT STILL EXPECT
3-6 INCHES OF WET SNOW OR MORE ACROSS MUCH OF THE AREA...WITH SNOW
RATIOS 10-15:1. WILL CONTINUE TO FINE TUNE THE FORECAST TONIGHT AND
TOMORROW.
FEW CHANGES WERE MADE TO THE MODEL CONSENSUS BEYOND FRIDAY...OTHER
THAN TO CONTINUE TO HIGHLIGHT THE NORTHERN UPSLOPE AREAS FOR
POSSIBLE LINGERING SNOW/SNOW SHOWERS INTO SATURDAY. THE ACTIVE
WEATHER PATTERN WILL CONTINUE WITH THE NEXT ROUND SLIDING IN TOWARD
SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 646 PM EDT TUE APR 9 2013
DRIER AIR WILL CONTINUE TO AFFECT IWD AND CMX AND CONTINUE THE VFR
CONDITIONS THERE AS HIGH CLOUDS FROM STORM SYSTEMS PASSING BY TO THE
SOUTH MOVE THROUGH. AT SAW...DRIER AIR IS SLOWER TO COME IN AND THE
MVFR CIG THAT IS THERE EARLY THIS EVENING WILL DISSIPATE AND VFR
CONDITIONS ARE THEN EXPECTED FOR THE REST OF THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 PM EDT TUE APR 9 2013
TONIGHT THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO N WINDS TO AROUND 25 KT
TUE INTO WED. NE WINDS ARE EXPECTED TO INCREASE TO GALES TO 35 KT
WED NIGHT INTO THU NIGHT...MAINLY OVER THE WEST...BEFORE DIMINISHING
BACK TO 25 KT ON FRIDAY. WINDS ARE EXPECTED TO DIMINISH BLO 20 KTS
FRI NIGHT INTO SAT AND HIGH PRES BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING
FOR LSZ162-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 PM EDT TUE APR 9 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOWS OVER
HUDSON BAY AND THE THE CENTRAL ROCKIES AND A RIDGE OVER THE SE CONUS
LEAVING CONFLUENT WRLY FLOW THROUGH NRN MN INTO NRN LAKE SUPERIOR.
AT THE SFC... A TROUGH STRETCHED THROUGH CNTRL KS INTO SRN IA FROM
LOW PRES OVER WRN TX. A WARM FRONT EXTENDED FROM SRN IA AND NRN IL
INTO NRN OH. NRLY FLOW HAD INCREASED THROUGH UPPER MI BEHIND A COLD
FRONT AS HIGH PRES OVER SASK BUILDS TOWARD NRN ONTARIO.
A LARGE AREA OF RAIN FROM CNTRL WI INTO FAR SRN UPPER MI WAS
SUPPORTED BY UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 150KT
250-300 MB JET STREAK OVER NRN ONTARIO AND LOWER LEVEL RESPONSE WITH
300K-305K (750-650 MB) ISENTROPIC ASCENT NORTH OF THE WARM FRONT.
THE PCPN AMOUNTS HAVE BEEN LIMITED AS AN MCS THROUGH SRN WI HAS
REDUCED MOISTURE INFLOW TO THE NORTH.
TONIGHT INTO WED...
ALTHOUGH THE FIRST BATCH OF PCPN OVER SRN UPPER MI
WILL MOVE OFF TO THE EAST THIS EVENING ANOTHER WEAK SHORTWAVE
EMERGING FROM THE PLAINS COMBINED ANOTHER INCREASE IN UPPER LEVEL
JET RIGHT ENTRANCE UPPER LEVEL DIV AND CONTINUED ISENTROPIC ASCENT
OVER THE REGION IS EXPECTED TO BRING ANOTHER ROUND OF PCPN
OVERNIGHT INTO WED MORNING. THERE IS SOME UNCERTAINTY WITH THE
TIMING AS THE GFS MOVES THE PCPN OUT MORE QUICKLY THAN THE
NAM/GEM/ECMWF.
SINCE THE THERE WAS PROMINENT LOWER LEVEL (285-290K ISENTROPIC
DESCENT) WITH DRIER AIR FLOWING TOWARD THE REGION HIGHER POPS WERE
LIMITED TO THE FAR SOUTH WITH A SHARP GRADIENT TO THE NORTH. NAM
TEMP PROFILE WITH A 1C-2C LAYER BETWEEN 800-700 MB SUGGESTS THAT
SLEET WILL BE THE PREDOMINANT PCPN TYPE IN THE AREA OF GREATEST QPF
WITH MAINLY SN/PL ON THE NRN EDGE. SOME FZRA MAY ALSO BE POSSIBLE
BUT SHOULD BE LESS SIGNIFICANT GIVEN THE SMALL WARM AREA ON THE FCST
SOUNDINGS.
CLOUDS/WIND SHOULD REDUCE DIURNAL TEMP RANGE. TEMPS ARE EXPECTED TO
REMAIN JUST AT OR BELOW FREEZING OVER THE SOUTH AND IN THE UPPER 20S
TO AROUND 30 OVER THE NORTH TONIGHT WITH HIGHS WED ONLY IN THE MID
30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
MUCH OF THE ATTENTION OF THIS FORECAST WILL BE ON THE UPCOMING
WINTER WEATHER EXPECTED THURSDAY THROUGH THE START OF THE WEEKEND.
FOR HYDROLOGICAL CONCERNS...THERE IS STILL 10-30 PLUS INCHES OF SNOW
STILL ON THE GROUND OVER THE MUCH OF THE HIGHER TERRAIN OF NORTHERN
UPPER MICHIGAN /SEE THE LATEST RTP OR NOHRSC SNOW ANALYSIS PAGE/.
ALTHOUGH WE WILL BE ADDING PRECIPITATION ON TOP OF THE SNOWPACK...A
QUICK MELT IS NOT FORESEEN AT THIS TIME...WITH TEMPERATURES FORECAST
TO REMAIN BELOW NORMAL THROUGH AT LEAST THE WEEKEND.
WEDNESDAY NIGHT WILL START OFF WITH STRONG HIGH PRESSURE SET UP
ACROSS ONTARIO...INFLUENCING MUCH OF OUR WEATHER INITIALLY WITH DRY
ENE FLOW FUNNELING IN FROM EASTERN ONTARIO. WENT AHEAD AND SLOWED
DOWN THE APPROACHING MOISTURE FROM THE SOUTHWEST ONCE AGAIN.
SOUTH CENTRAL UPPER MICHIGAN WILL CONTINUE TO BE RIGHT ALONG THE
NORTHERN PRECIPITATION SHIELD THROUGH MID MORNING THURSDAY. BY 18Z
THURSDAY THE SFC LOW SHOULD BE SET UP ACROSS SOUTHERN
WISCONSIN/NORTHERN ILLINOIS AND INDIANA.
AT THIS POINT THE BEST OPTION LOOKS TO FOLLOW A BLEND BETWEEN THE
12Z ECMWF AND NAM...WITH LESS INCLUSION OF THE QUICKER GFS.
CONFIDENCE IS INCREASING ON THE IDEA OF STRONG STRONG EAST TO
NORTHEASTERLY WINDS WEDNESDAY NIGHT THROUGH THURSDAY
EVENING...PARTICULARLY NEAR ESC AND MNM AND WESTERN LAKE SUPERIOR.
THE GFS...GIVEN THE WEAKER AND SFC LOW CENTERED FARTHER TO THE EAST
IS UNDERSTANDABLY LIGHTER WITH THE WIND FORECAST...BUT WILL HAS
30-35KT WINDS OVER FAR SW LAKE SUPERIOR AND OUR EASTERN LAKE
MICHIGAN ZONES.
SNOWFALL AMOUNT WITH THIS SYSTEM CONTINUE TO BE A CONCERN.
HOWEVER...WITH AS MUCH MODEL SPREAD STILL SHOWN...WILL NOT ISSUE ANY
SNOW HEADLINES...BUT CONTINUE TO MENTION THE POTENTIAL IN THE HWO.
THE 12Z ECMWF HAS BECOME MORE PROGRESSIVE...EJECTING THE 500MB LOW
TO EASTERN ONTARIO SATURDAY MORNING...OR 6-12 HOURS FASTER THAN THE
09/00Z RUN. THIS IS STILL QUITE A BIT SLOWER THAN THE MERGING GFS
SOLUTION...WITH THE LOW MOVING AS CLOSE AS CENTRAL LOWER
MICHIGAN...WHILE THE NAM/GFS TRACK IT ACROSS UPPER MICHIGAN. THE
09/12Z CANADIAN INITIALLY LOOKS TO BE A GOOD COMPROMISE BETWEEN THE
2 CAMPS...BUT IS MUCH WEAKER WITH LESS THAN A QUARTER INCH OF LIQUID
ACROSS THE MUCH OF THE CWA. THE GFS DOES NOT DO MUCH BETTER...WITH A
GOOD DRY LAYER SHOWING UP ON THE FCST SOUNDINGS BETWEEN 900 AND
700MB. SNOWFALL AMOUNTS COULD VARY SIGNIFICANTLY...BUT STILL EXPECT
3-6 INCHES OF WET SNOW OR MORE ACROSS MUCH OF THE AREA...WITH SNOW
RATIOS 10-15:1. WILL CONTINUE TO FINE TUNE THE FORECAST TONIGHT AND
TOMORROW.
FEW CHANGES WERE MADE TO THE MODEL CONSENSUS BEYOND FRIDAY...OTHER
THAN TO CONTINUE TO HIGHLIGHT THE NORTHERN UPSLOPE AREAS FOR
POSSIBLE LINGERING SNOW/SNOW SHOWERS INTO SATURDAY. THE ACTIVE
WEATHER PATTERN WILL CONTINUE WITH THE NEXT ROUND SLIDING IN TOWARD
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE APR 9 2013
NRLY UPSLOPE FLOW INTO SAW WILL CONTINUE TO SUSTAIN IFR CIGS THROUGH
MID AFTERNOON. HOWEVER...IMPROVENT TO MVFR IS EXPECTED BY LATE
AFTERNOON AND VFR THIS EVENING AS DRIER FROM NRN ONTARIO BUILDS INTO
THE REGION. SIMILARLY...AT IWD THE DRY AIR WILL ALSO HELP BOOST CIGS
FROM LOWER END MVFR TO VFR BY LATE AFTERNOON WHILE VFR CONDITIONS
WILL PERSIST AT CMX. WITH DRY NORTH WINDS CONTINUING OVERNIGHT INTO
WED...VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 PM EDT TUE APR 9 2013
TONIGHT THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO N WINDS TO AROUND 25 KT
TUE INTO WED. NE WINDS ARE EXPECTED TO INCREASE TO GALES TO 35 KT
WED NIGHT INTO THU NIGHT...MAINLY OVER THE WEST...BEFORE DIMINISHING
BACK TO 25 KT ON FRIDAY. WINDS ARE EXPECTED TO DIMINISH BLO 20 KTS
FRI NIGHT INTO SAT AND HIGH PRES BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING
FOR LSZ162-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
142 PM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP CUTOFF
OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE APR 9 2013
NRLY UPSLOPE FLOW INTO SAW WILL CONTINUE TO SUSTAIN IFR CIGS THROUGH
MID AFTERNOON. HOWEVER...IMPROVENT TO MVFR IS EXPECTED BY LATE
AFTERNOON AND VFR THIS EVENING AS DRIER FROM NRN ONTARIO BUILDS INTO
THE REGION. SIMILARLY...AT IWD THE DRY AIR WILL ALSO HELP BOOST CIGS
FROM LOWER END MVFR TO VFR BY LATE AFTERNOON WHILE VFR CONDITIONS
WILL PERSIST AT CMX. WITH DRY NORTH WINDS CONTINUING OVERNIGHT INTO
WED...VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO NE WINDS TO AROUND 25
KT TUE INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT BEFORE DIMINISHING BACK TO 25 KT ON FRIDAY. WINDS ARE
EXPECTED TO DIMINISH BLO 20 KTS FRI NIGHT INTO SAT AND HIGH PRES
BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
136 PM CDT TUE APR 9 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECAST SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM CDT TUE APR 9 2013
TRICKY AVIATION FORECAST FOR THE NEXT 24 TO 30 HOURS AS MULTIPLE
ROUNDS OF PRECIP BRING DIFFERING TYPES OF WX AND CIGS/VSBYS.
CURRENTLY ANTICIPATE THE SNOW TYPE ALONG AND NORTHWEST OF RWF TO
STC TO BE IN THE FORM OF SNOW...WITH RAIN AND SOME SLEET MIXED TO
THE SOUTHEAST. A LULL THIS AFTERNOON WILL GIVE WAY TO ANOTHER
ROUND THIS EVENING AND PRECIP WILL TRANSITION TO MAINLY SNOW AT MSP/RNH
BETWEEN 04-06Z AND EAU AROUND 10Z. ANOTHER LULL IS EXPECTED
WEDNESDAY MORNING. CIGS ARE HIGHLY VARIABLE...RANGING FROM VFR TO
IFR...BUT AS THE PRECIP CONTINUES TO DIMINISH THIS AFTERNOON
EXPECT CIGS TO IMRPOVE A BIT.
KMSP...FRIST ROUND IS JUST ABOUT DONE WITH ONLY A FEW SHOWERS
LINGERING INTOT HE EARLY EVENING. ANOTHER ROUND WILL ARRIVE LATE
THIS EVENING AND SHOULD BE MOSTLY IN THE FORM OF SNOW...WITH
PERHAPS A LITTLE SLEET ALSO MIXING IN INITIALLY. MAINLY VFR
CIGS/VSBYS TODAY AND THIS EVENING WILL GIVE WAY TO MVFR/IFR
CONDITIONS WITH THE NEXT ROUND TONIGHT.
/OUTLOOK FOR KMSP/
WED...IFR WITH SN. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 15G12 KTS.
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
348 PM MDT TUE APR 9 2013
.SHORT TERM...VALID FOR TONIGHT...
WE DECIDED TO CANCEL THE REST OF THE WINTER STORM WARNING WITH THE
AFTERNOON FORECAST. THE MAIN ATTENTION-GRABBER TONIGHT WILL BE THE
COLD TEMPERATURES /WITH RECORD LOWS POSSIBLE IN SOME LOCATIONS/.
AS OF 21 UTC...MOISTURE CHANNEL IMAGERY SUGGESTS THE CLOSED LOW AT
500-HPA IS CENTERED ACROSS COLORADO...AND EVEN HIGH-LEVEL MOISTURE
SAMPLING SHOWS A WEAKENING DEFORMATION ZONE OVER SOUTHERN MONTANA.
THAT REFLECTS THE NOW-WEAKENING FORCING THAT GENERATED SNOW DURING
THE PAST 24 HOURS...AND CONFIRMS THE MODEL EXPECTATION FOR 500-300
HPA Q-VECTOR CONVERGENCE TO BE ON THE DOWNSWING IN OUR AREA. THERE
IS ANOTHER BATCH OF MOISTURE WITH COOLING CLOUD TOPS HEADED TO THE
NORTH ACROSS WYOMING AS OF MID AFTERNOON AS WELL...AND THAT IS THE
FEATURE OF INTEREST HEADING INTO TONIGHT. IT LOOKS LIKE THE 12 UTC
NAM HANDLES THIS SCENARIO WELL...AND IT DOES SHOW RENEWED SNOWFALL
IN EXTREME SOUTHEASTERN MT /NAMELY FAR SOUTHERN CARTER COUNTY NEAR
ALZADA AND ALBION/ OVERNIGHT. THE 20 UTC RAP HAS A SIMILAR TYPE OF
SOLUTION...BUT EXTENDS ITS MOISTURE ANOTHER 50 TO 75 MILES FURTHER
WEST AFTER 06 UTC. THAT DOES NOT FIT WITH THE REST OF THE GUIDANCE
FROM 12 UTC...SO RIGHT NOW IT LOOKS LIKE A BIT OF AN OUTLIER.
SO...WE EXTRAPOLATED OBSERVATIONAL TRENDS AND LEANED ON THE 12 UTC
NAM TO BUILD THE OVERNIGHT FORECAST. THAT GENERALLY MEANT REDUCING
POPS AND SNOW AMOUNTS FROM SHERIDAN TO EKALAKA...WITH POPS LEFT IN
THE LIKELY RANGE ONLY FROM ABOUT BIDDLE TO ALBION AND ALZADA AFTER
06 UTC. AN INCH OR TWO OF ADDITIONAL SNOWFALL IS ADVERTISED ACROSS
THAT AREA AS WELL...BUT WEB CAMERA IMAGES ALONG HIGHWAY 212 DURING
THE AFTERNOON SUGGEST THAT CONDITIONS HAVE GREATLY IMPROVED. THERE
WAS SIMILAR EVIDENCE ACROSS THE REST OF THE WARNED AREA...AND ONLY
FLURRIES ARE EVEN BEING REPORTED AT SHERIDAN NOW. THUS...THERE ARE
NO LONGER ENOUGH CURRENT OR EXPECTED IMPACTS TO KEEP WARNINGS UP.
OTHERWISE...THE TIMING OF CLEARING WILL BE THE KEY TO HOW FAR LOWS
FALL. A FRESH SNOW PACK AND SURFACE RIDGING WITH LIGHT FLOW IN THE
BOUNDARY LAYER WILL MAKE FOR FAVORABLE RADIATIONAL COOLING WHERE A
CLEAR SKY DOES DEVELOP. WE USED THE 12 UTC MET /NAM-BASED/ MOS AND
MID-AFTERNOON DEWPOINTS AS A GUIDE FOR OVERNIGHT LOWS. SHERIDAN TO
BAKER IS THE CORRIDOR LEAST LIKELY TO HAVE ENOUGH REDUCTION IN THE
CLOUDS FOR EFFICIENT RADIATIONAL COOLING...BUT THAT AREA WILL ALSO
HAVE THE SHORTEST DISTANCE TO FALL TO DROP BELOW ABOUT 15 DEGREES.
WE HAVE ENOUGH CONFIDENCE IN THE FORECAST TO BELIEVE DAILY RECORDS
COULD BE TIED OR FALL AT BILLINGS...MILES CITY...AND SHERIDAN. ONE
INTERESTING THING TO NOTE IS THAT DAILY RECORD LOWS MAY BE SET FOR
BOTH APRIL 9TH AND THE 10TH IF TEMPERATURES FALL FAST ENOUGH PRIOR
TO MIDNIGHT AT BILLINGS AND MILES CITY...WHERE THE CURRENT RECORDS
FOR THE 9TH ARE 16 DEGREES /SET IN 1973/. FOR APRIL 10TH...CURRENT
RECORDS ARE AT 11 DEGREES AT BILLINGS AND 14 DEGREES AT MILES CITY
/BOTH FROM 1940/ AND 11 DEGREES AT SHERIDAN /SET IN 1933/. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...MON...TUE...
INTERESTING PERIOD OF WEATHER FOR THE REST OF THIS WEEK AND INTO
EARLY NEXT WEEK. MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT IN
MOVING OUR CURRENT WEATHER MAKER EASTWARD INTO THE HIGH PLAINS BY
WEDNESDAY AFTERNOON.
THE FIRST SYSTEM TO IMPACT THE REGION WILL ARRIVE THIS COMING
THURSDAY...AS MODELS SHOW AN AMPLE AMOUNT OF MOISTURE AVAILABLE TO
WARRANT UPPING THE POP FORECASTS ACROSS MOST OF THE CWA. SOME
LARGE SCALE FORCING WILL ALSO BE AVAILABLE TO HELP ENHANCE THE
CHANCES OF PRECIPITATION.
BY FRIDAY WE TRANSITION INTO A MORE NORTHWESTERLY FLOW AND
PARTIAL RIDGING...BEFORE A FAIRLY STRONG WESTERLY UPPER LEVEL JET
CROSSES INTO CENTRAL WYOMING...LEAVING MT ON THE COLDER
CYCLONIC SIDE. THIS WILL HELP TO KEEP TEMPERATURES BELOW AVERAGE
AS WELL AS KEEP THE POP FORECASTS ABOVE CLIMO.
NUMEROUS BURSTS OF SHORTWAVE ENERGY AT THE MID LEVELS WILL RIDE
THE JET AND BRING THE POTENTIAL FOR ANOTHER SIGNIFICANT LATE
SEASON WINTER STORM BY EARLY NEXT WEEK. HOWEVER...AT THIS
TIME...THE TRACK OF THE MID LEVEL LOW NEEDS TO BE MONITORED..AS IT
MAY NOT BE IN THE MOST FAVORABLE POSITION FOR SOUTH CENTRAL
MONTANA...AS MOST OF THE JET DYNAMICS AND Q-VECTOR CONVERGENCE ARE
WELL SOUTH INTO CENTRAL WYOMING. A SHIFT OF THIS TRACK SLIGHTLY TO
THE NORTH MAY TRIGGER THE NEED FOR HIGHER POPS. SINGER
&&
.AVIATION...
SNOW SEEMS TO HAVE WINDED DOWN AT ALL TERMINALS...WHICH IN TURN IS
RAISING CEILINGS AND INCREASING VISIBILITIES. EXPECTING CONDITIONS
TO GET BETTER THROUGH THE EVENING HOURS AND INTO TOMORROW. THERE
IS A CHANCE FOR A LINGERING SNOW SHOWER...ESPECIALLY NEAR THE
MOUNTAINS. VFR CONDITIONS SHOULD PREVAIL ON WEDNESDAY AS THE STORM
SYSTEM EXITS TO THE EAST. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 012/044 032/054 032/052 035/053 030/048 026/046 027/048
01/U 53/W 22/W 34/W 33/W 33/W 33/W
LVM 013/053 031/055 026/053 032/051 023/044 020/044 020/045
01/B 73/W 22/W 34/W 33/W 33/W 33/W
HDN 012/043 029/053 030/053 034/055 031/049 026/047 026/048
11/B 55/W 22/W 34/W 33/W 33/W 23/W
MLS 014/040 025/049 029/049 032/052 032/047 028/043 026/047
11/U 35/W 23/W 25/W 43/W 33/W 22/W
4BQ 011/035 016/044 027/048 030/052 031/047 027/044 026/044
31/B 25/W 23/W 23/W 43/W 33/W 34/W
BHK 017/036 020/041 026/045 026/047 030/041 025/041 024/042
11/B 14/W 23/W 14/W 43/W 33/W 22/W
SHR 011/040 024/049 027/050 029/052 027/044 024/043 024/045
41/B 44/W 33/W 23/W 43/W 45/W 34/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1137 AM MDT TUE APR 9 2013
.SHORT TERM...VALID FOR TDY AND WED...
THE WINTER STORM WARNING FOR THE BEARTOOTH AND RED LODGE FOOTHILLS
WILL BE ALLOWED TO EXPIRE AS PLANNED AT NOON. THERE ARE STILL WEAK
RADAR RETURNS IN THOSE AREAS...AND WEAK UPSLOPE FLOW WILL PROBABLY
KEEP SOME LIGHT SNOW GOING ALONG PART OF THE FOOTHILLS FOR A WHILE
THIS AFTERNOON LIKE THE 12 UTC NAM AND 16 UTC RAP SHOW. HOWEVER...
THE SUN IS ACTUALLY TRYING TO PEAK THROUGH NEAR NYE PER RECENT WEB
WEB CAMERA IMAGES...SO LOW-LEVEL DRYING IS BEGINNING. THE HEADLINE
CAN THUS BE DROPPED IN THOSE AREAS. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 935 AM MDT TUE 9 APR 2013...
WE UPDATED THE FORECAST TO DROP POPS OUT OF THE FORECAST TODAY FOR
THE CITY OF BILLINGS...AND INSTEAD WENT WITH THE IDEA OF FLURRIES.
RADAR IMAGERY HAS SHOWN A HALT TO THE NORTHWARD ADVANCE OF SNOW IN
FAR SOUTHERN MT OVER THE LAST ONE TO TWO HOURS THANKS TO LOW-LEVEL
DRYING. WE ALSO ADDED FLURRIES ALONG THE REST OF THE NORTH SIDE OF
THE MORE ESTABLISHED SNOW AS WELL...FROM LIVINGSTON ALL THE WAY TO
AROUND BAKER. LIVINGSTON HAS HAD MORE LEGITIMATE LIGHT SNOW WITH A
VISIBILITY UNDER 3 MILES AT TIMES THANKS TO UPSLOPE ENHANCEMENT IN
THAT AREA...BUT AS OF 15 UTC THAT HAS TRANSITIONED TOWARD A FLURRY
MODE TOO...SO WE DECIDED TO GO THAT ROUTE INSTEAD OF ADDING LIKELY
OR CATEGORICAL POPS LIKE WE HAD BEEN CONSIDERING.
OTHERWISE...THE REST OF THE FORECAST APPEARS ON TRACK. WEB CAMERAS
SHOW SNOW CONTINUING IN THE BEARTOOTH AND RED LODGE FOOTHILLS...SO
WE WILL LEAVE THE WARNING FOR THOSE AREAS IN EFFECT UNTIL NOON. WE
WILL PROBABLY BE ABLE TO LET IT GO AT THAT POINT THOUGH AS IMPACTS
SHOULD BE WANING EVEN IF SOME LIGHT SNOW CONTINUES BEYOND THEN. WE
WILL ALSO LEAVE THE WINTER STORM WARNINGS OVER SHERIDAN COUNTY AND
THE THE NORTHEAST BIG HORN MOUNTAINS UP INTO FAR SOUTHERN MT UP AS
SNOW CONTINUES THERE AS WELL. WE DID SOME SMALL FINE-TUNING TO THE
POPS AND SNOW AMOUNTS FOR THOSE AREAS...THOUGH WE COULD NEED TO DO
A BIT MORE TOWARD MIDDAY. IN GENERAL...ANOTHER 2 TO 4 INCHES LOOKS
FEASIBLE IN THOSE AREAS TODAY. FINALLY...WE LARGELY LEFT HIGHS FOR
TODAY ALONE...BUT THE TWO NEW SETS OF GUIDANCE WE HAVE SO FAR THIS
MORNING DISAGREE ON WHETHER SUBTLE CHANGES MIGHT BE NEEDED. THE 12
UTC NAM SAYS WE MIGHT BE A BIT TOO WARM IN PLACES...WHILE THE LAST
FEW LAMP GUIDANCE CYCLES SUGGEST WE MAY BE A BIT TOO COOL FOR SOME
SPOTS. THE GOING FORECAST IS A GOOD COMPROMISE AND IS CLOSE TO THE
06 UTC MULTI-MODEL CONSENSUS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
DETAILS IN THE EXTENDED FORECAST WILL SUBJECT TO SHIFTS IN TIMING AND
STRENGTH OF DISTURBANCES MOVING THROUGH THE REGION BUT THE OVERALL
PATTERN IS EASY TO DEPICT. WAVE APPROACHES MONTANA ON THURSDAY AND
DEEPENS A BIT THURSDAY NIGHT WITH A PACIFIC FRONT THURSDAY NIGHT.
UNSETTLED NORTHWEST FLOW CONTINUES UNTIL SATURDAY WHEN A DEEPER
SYSTEM BEGINS MOVING INTO THE PACIFIC NORTHWEST INDUCING HEIGHT
FALLS OVER MONTANA AND WYOMING. THIS SYSTEM WILL DEEPEN AND MOVE
INTO WESTERN MONTANA SATURDAY NIGHT. FOR SUNDAY AND BEYOND THE JET
STREAM WILL REMAIN WELL SOUTH OF THE REGION SUPPORTING BELOW
NORMAL TEMPERATURES AND SCATTERED SHOWER ACTIVITY.
THE THURSDAY SYSTEM COULD HAVE SOME DECENT SHOWER ACTIVITY
ASSOCIATED WITH IT BECAUSE THERE IS A DECENT TAP INTO THE PACIFIC
FOR MOISTURE SO WILL HAVE TO WATCH TO SEE HOW QUICKLY THE HEIGHT
FALLS OCCUR AND THE TIMING OF THE FRONT.
AT THIS POINT IN TIME THE TRACK OF THE WEEKEND SYSTEM APPEARS TO
BE FAR ENOUGH NORTH THAT SOUTHERN MONTANA AND NORTHERN WYOMING
WILL NOT SEE SIGNIFICANT IMPACTS. BEST PRECIPITATION SHOULD WRAP
INTO THE NORTH SIDE OF THE LOW WITH PERIODS OF DRY SLOTTING
LIKELY ACROSS SOUTHERN MONTANA. BORSUM
&&
.AVIATION...
MAJOR STORM SYSTEM OVER WYOMING AND COLORADO SPREADING SNOW AND
LOW CLOUDS INTO THE SOUTHERN PORTION OF THE FORECAST AREA. UPSLOPE
WINDS KEEPING A THREAT OF MVFR CEILINGS AT MOST OF THE TAF SITES
TODAY. SNOW HAS ENDED FOR MOST SITES EXCEPT KSHR WHERE IT WILL
CONTINUE FOR MOST OF THE DAY. IFR CEILINGS ARE POSSIBLE SOUTH OF A
KBIL-KMLS WITH MOUNTAIN OBSCURATIONS CONTINUING. BORSUM/SCHULTZ
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 032 017/044 032/054 032/053 031/055 032/053 029/052
1/M 01/U 44/W 22/W 34/W 33/W 33/W
LVM 035 016/051 033/056 030/053 030/053 027/050 025/048
1/M 01/B 42/W 22/W 34/W 33/W 33/W
HDN 029 015/043 027/053 028/053 026/056 029/054 026/052
6/J 11/B 34/W 22/W 34/W 33/W 33/W
MLS 029 016/040 026/048 028/051 026/052 029/050 027/045
1/E 11/U 24/W 23/W 25/W 43/W 23/W
4BQ 024 013/036 021/044 024/049 024/053 027/052 024/049
9/S 31/B 13/W 22/W 23/W 43/W 22/W
BHK 025 014/036 020/041 024/046 024/047 024/044 022/042
1/C 11/B 13/W 23/W 14/W 43/W 22/W
SHR 025 012/040 024/049 027/049 025/053 027/050 025/049
+/S 21/B 23/W 33/W 23/W 43/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR ZONES 36>38-58.
WY...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1243 PM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1234 PM CDT TUE APR 9 2013
HIGH CLOUDS ARE THINNING ACROSS THE NORTH AND THAT SHOULD BE GOOD
FOR PARTLY SUNNY SKIES THIS AFTERNOON. COOL FLOW OUT OF THE HIGH
AND SNOW COVER BEING VERY TOUGH ON HIGH TEMPERATURES TODAY.
LOWERED THE FORECAST HIGH ABOUT 2 TO 5 DEGREES ACROSS THE SOUTHWEST
AND EAST CENTRAL. BOWMAN RADAR SHOWS MAINLY FLURRIES NOW...BUT
HETTINGER SHOWERS LIGHT SNOW. DROPPED THE CHANCE OF SNOW AND WILL
GO WITH FLURRIES SOUTH OF BISMARCK AND JAMESTOWN THIS AFTERNOON AS
NO SNOW SHOWING UP BETWEEN ABERDEEN AND MOBRIDGE YET.
UPDATE ISSUED AT 931 AM CDT TUE APR 9 2013
AT 9 AM CDT...COLD SURFACE HIGH REMAINS ACROSS SASKATCHEWAN INTO
MONTANA. LARGE EARL SPRING STORM CONTINUES TO DEVELOP FROM THE
ROCKIES INTO THE CENTRAL PLAINS. ALL BUT THE VERY SOUTHERN TIER
OF COUNTIES WILL SEE SOME HIGH CLOUDINESS. THE SOUTHERN COUNTIES
WILL SEE CONTINUOUS LIGHT SNOW OR FLURRIES. ADDED FLURRIES TO A
LARGER PORTION OF THE SOUTHWEST FOR THE MORNING HOURS..AS BAKER
MONTANA AND BEACH. ARE REPORTING SOME FLURRIES THIS MORNING.
TEMPERATURES LOOK OK SO FAR.
UPDATE ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1234 PM CDT TUE APR 9 2013
AT 12 PM CDT SURFACE HIGH PRESSURE ACROSS SASKATCHEWAN AND MONTANA
WAS LARGELY RESPONSIBLE FOR THE VFR CONDITIONS ACROSS THE REGION.
EXPECT VFR TO CONTINUE THROUGH TONIGHT. THEN AFTER 09Z...SEE SOME
LOW LEVEL MOISTURE CREEPING UP THE JAMES RIVER VALLEY AND WENT
WITH BROKEN CEILINGS IN THE MVFR CATEGORY AT KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...RK
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1238 PM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1235 PM CDT TUE APR 9 2013
STATUS QUO ON -SN EVOLUTION ACROSS THE FAR SOUTHERN FA. -SN
REMAINS TO THE SOUTH OF OUR FORECAST AREA AND CONFIDENCE PRETTY
HIGH THAT LITTLE WILL FALL ALONG THE BORDER AREA REMAINDER OF
TODAY AND LIKELY TONIGHT. MAINTAINED POPS WHICH WERE LOWERED ON
PREVIOUS UPDATE. TEMPERATURES ANOTHER STORY. FILTERED APRIL SOLAR
IN PLACE BUT TEMPERATURES NOT LIKELY TO MAKE PREVIOUSLY EXPECTED
MAXIMUM TEMPERATURES ESPECIALLY ACROSS THE DVL BASIN. LOWERED
MAXIMUM VALUES SEVERAL DEGREES AND A DEGREE OR SO ELSEWHERE.
ELSEWHERE MINOR ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 935 AM CDT TUE APR 9 2013
FORECAST CHALLENGE FOR UPDATES TODAY WILL BE SNOW CHANCES ALONG
ND/SD/MN BORDER AREA AND TEMPERATURES.
SO FAR DRIER AIR WINNING OUT WITH NORTHERN EDGE OF SNOW BAND WITH
FIRST WAVE FROM BIG STORM SOUTH OF OUR FA AND THE RED BASIN.
EXPECT THESE TRENDS TO CONTINUE TODAY AND HAVE DOUBTS WHETHER ANY
OF THE FAR SOUTHERN FA WILL GET ANY SNOW. DID NOT COMPLETELY PULL
POPS BUT LOWERED TO LOW CHANCES ALONG BORDER AREA TO BE SAFE. VERY
COLD START TODAY HOWEVER WITH COLD ADVECTION OVER AND SOME
FILTERED EARLY APRIL SOLAR TEMPERATURES SHOULD RESPOND. DID NOT
MAKE ANY CHANGES WITH TEMPERATURES BUT WILL MONITOR FOR NEXT
UPDATE. ONLY OTHER CHANGES WERE ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1236 PM CDT TUE APR 9 2013
BRIEF INTERVAL OF LOWER CLOUDINESS EMANATING FROM UPPER MIDWEST
SYSTEM HAS MOVED AWAY FROM KFAR...LOOK FOR CIRRUS TO PREVAIL FROM
KDVL-KFGF-KTVF THROUGH PERIOD WITH SOME MID CLOUD ELSEWHERE. WINDS
TO REMAIN NORTHERLY NEAR 15 KT THROUGH THE EVENING...EASING BELOW 10
KTS TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...WJB
AREA FORECAST DISCUSSION
NWS TULSA OK
1128 AM CDT TUE APR 9 2013
...UPDATE...
.DISCUSSION...
STRONG COLD FRONT WHICH HAS PASSED THROUGH MUCH OF THE TEXAS
PANHANDLE AND PORTIONS OF NW OK HAS CONTINUED TO SWEEP STEADILY
SOUTHEASTWARD THROUGH THE MORNING AIDED BY A BROAD REGION OF
STRONG PRESSURE RISES. CURRENT OBSERVATIONS AND 12Z UPPER AIR DATA
REVEAL THE STRENGTH OF THE ADVANCING COLD AIRMASS WITH THE CURRENT
FRONTAL POSITION A BIT FASTER THAN THE RECENT 12Z NAM...AND WITH
THE 12Z GFS HAVING NOTABLE INITIALIZATION ERRORS WITH THE
MAGNITUDE OF THE COLD AIR. RECENT RAP RUNS ALONG WITH LCL WRF RUNS
HAVE CONTINUED TO TREND FASTER WITH THE FRONTAL PROGRESSION INTO
EASTERN OK AND THE UPDATED FORECAST WILL REFLECT THIS FASTER
ARRIVAL.
THE PRE-FRONTAL WARM SECTOR REMAINS STRONGLY CAPPED PER 12Z
REGIONAL SOUNDINGS AND APPEARANCE OF VISIBLE SATELLITE IMAGERY.
FORECAST SOUNDINGS ACROSS THE WARM SECTOR MAINTAIN A SIZABLE WARM
LAYER AND BREAKING IT WOULD TAKE APPRECIABLE SFC HEATING AND/OR
LOW LEVEL CONVERGENCE WHICH IS NOT LIKELY AHEAD OF THE FRONT...THUS
THE AFTERNOON PRECIP CHANCES WERE LOWERED BELOW MENTIONABLE
LEVELS.
CONVECTION WILL EXPAND AND INTENSIFY ALONG THE FRONTAL BOUNDARY AS
IT PUSHES SOUTHEASTWARD THIS AFTERNOON AND EVENING...WITH
AVAILABLE INSTABILITY AND SHEAR WITHIN THE FRONTAL ZONE SUPPORTING
A RISK OF SEVERE WEATHER. ANY PRE-FRONTAL CELLULAR STORMS WILL
LIKELY REMAIN RATHER LIMITED IN BOTH COVERAGE AND DURATION AS THE
STRONG FRONTAL SURGE INTERCEPTS ANTICIPATED STORM MOTIONS WITHIN A
SHORT TIME WINDOW.
ADDITIONALLY...GIVEN THE FORECAST WIND FIELDS AND FASTER FRONTAL
SURGE THE CONVECTION WILL QUICKLY FOCUS IN THE POST FRONTAL ZONE
WHICH IS ALREADY EVIDENT ACROSS WEST TEXAS. THIS AGAIN WOULD FAVOR
A NARROW ZONE OF SFC BASED CONVECTION WITHIN THE FRONTAL ZONE
WHICH WOULD ALLOW FOR POCKETS OF DAMAGING WIND POTENTIAL...WITH
THE SVR MODE QUICKLY TRANSITIONING TO LARGE HAIL BEHIND THE FRONT.
THE TORNADIC RISK APPEARS RATHER SMALL ESPECIALLY FOR ANY DISCRETE
SUPERCELLS ACROSS THE FORECAST AREA. ALSO...SHEAR VECTORS ARE NOT
OVERLY SUPPORTIVE OF QLCS TORNADOES BUT THIS POTENTIAL WILL BE
MONITORED GIVEN THE INCREASINGLY STRONG LOW LEVEL SHEAR TONIGHT.
THE UPDATED FORECAST WILL ADJUST WINDS THIS EVENING...AND MAINTAIN
FORECAST HIGH TEMPS WHICH EXPECT AT LEAST SOME BREAKS IN THE
AFTERNOON CLOUDS. PRECIP AMOUNTS WILL ALSO BE INCREASED FOR LATE
TONIGHT ACROSS NE OK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 79 39 46 30 / 10 90 80 10
FSM 82 56 57 34 / 10 80 90 30
MLC 80 41 46 31 / 10 90 80 10
BVO 78 36 47 28 / 10 90 80 10
FYV 77 55 56 33 / 10 80 90 30
BYV 78 59 61 34 / 10 80 90 30
MKO 79 43 46 30 / 10 90 80 20
MIO 78 44 45 30 / 10 90 90 20
F10 79 39 47 30 / 10 90 80 10
HHW 80 56 56 34 / 10 90 80 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
608 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WED NIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROAD-BRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
STATIONARY FRONT THRU NY IS EXPECTED TO SAG SLOWLY INTO NRN PA
LATER TONIGHT...POSSIBLY BRINGING SOME SHOWERS AND MVFR/IFR. THIS
BOUNDARY IS EXPECTED TO REMAIN IN THE VCNTY OF CNTRL PA THRU AT
LEAST WED WHICH WOULD SUGGEST THE BEST CHANCE FOR RAIN/THUNDER
SHOWERS AND REDUCED CONDITIONS WILL BE OVER CENTRAL AND NRN
TERMINALS.
.OUTLOOK...
THU...EARLY AM LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS NORTH.
FRI...RAIN/LOW CIGS POSS...ESP EARLY. SHRA POSS NW PM.
SAT-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...GARTNER/STEINBUGL
AVIATION...DANGELO/LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
403 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WED NIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROADBRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
CU BUILDING ALONG AND JUST BEHIND THE WARM FRONT. BRIEF/ISOLD SHRA
ARE POSS WITH JUST AN OUTSIDE CHC OF THUNDER AS A SMALL AMT OF
CAPE EXPECTED IN THE WEST. WILL NOT MENTION T IN TAFS AT THIS
POINT DUE TO EXTREMELY LOW CHC. WIND WILL STAY 10-15KTS THROUGH
MOST OF THE EVENING. MCV/REMNANTS MOVING ACROSS LAKE ERIE/LWR ONT.
A WEAK TAIL OF VORT IS DRAPED SWRD AND COULD MEET UP WITH THE BEST
CAPE TO GENERATE SOME SHRA/TSRA IN BFD BEFORE 00Z. OTHERWISE...THE
NEXT WAVE OF LIFT COMES ALONG LATER THIS EVENING/TONIGHT. WILL
HOLD MENTIONS OF SHRA IN MOST TAFS FOR AT LEAST THE FIRST PART OF
THE NIGHT. WIND ALOFT GETS PRETTY STRONG AND LOWERS AS THE LL JET
SLINGS BY. THE STRONG WINDS GET DOWN TO FL010/015 IN THE MIDDLE OF
NIGHT...BUT SLACKEN SIGNIFICANTLY AFTER 09Z. WILL THEN NOT MENTION
LLWS AFTERWARD. SCT/NWRS SHRA ACROSS THE N WED AFTN/NIGHT. BUT
LESS OF A CHC OVER MOST TERMINALS WITH BEST MSTR POOLING AND
THERMAL GRADIENT WELL TO THE NORTH OF UNV/IPT. WILL MENTION MVFR
CIGS IN THE MORNING FOR IPT/UNV...BUT ALLOW FOR SOME MIXING TO
RAISE THE CIGS IN THE AFTN WED. WAVES OF LOW PRESSURE THEN
CONTINUE TO MOVE W-E ALONG THE WAVY FRONT WED NIGHT AND THURSDAY
IN ADVANCE OF SYSTEM WHICH WILL WRAP UP OVER THE MIDWEST/OH VALLEY
AND MOVE THROUGH LATE THURS/EARLY FRI.
.OUTLOOK...
THU...EARLY AM LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS NORTH.
FRI...RAIN/LOW CIGS POSS...ESP EARLY. SHRA POSS NW PM.
SAT-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...GARTNER/STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
309 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WEDNIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROADBRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
CU BUILDING ALONG AND JUST BEHIND THE WARM FRONT. BRIEF/ISOLD SHRA
ARE POSS WITH JUST AN OUTSIDE CHC OF THUNDER AS A SMALL AMT OF
CAPE EXPECTED IN THE WEST. WILL NOT MENTION T IN TAFS AT THIS
POINT DUE TO EXTREMELY LOW CHC. WIND WILL STAY 10-15KTS THROUGH
MOST OF THE EVENING. MCV/REMNANTS MOVING ACROSS LAKE ERIE/LWR ONT.
A WEAK TAIL OF VORT IS DRAPED SWRD AND COULD MEET UP WITH THE BEST
CAPE TO GENERATE SOME SHRA/TSRA IN BFD BEFORE 00Z. OTHERWISE...THE
NEXT WAVE OF LIFT COMES ALONG LATER THIS EVENING/TONIGHT. WILL
HOLD MENTIONS OF SHRA IN MOST TAFS FOR AT LEAST THE FIRST PART OF
THE NIGHT. WIND ALOFT GETS PRETTY STRONG AND LOWERS AS THE LL JET
SLINGS BY. THE STRONG WINDS GET DOWN TO FL010/015 IN THE MIDDLE OF
NIGHT...BUT SLACKEN SIGNIFICANTLY AFTER 09Z. WILL THEN NOT MENTION
LLWS AFTERWARD. SCT/NWRS SHRA ACROSS THE N WED AFTN/NIGHT. BUT
LESS OF A CHC OVER MOST TERMINALS WITH BEST MSTR POOLING AND
THERMAL GRADIENT WELL TO THE NORTH OF UNV/IPT. WILL MENTION MVFR
CIGS IN THE MORNING FOR IPT/UNV...BUT ALLOW FOR SOME MIXING TO
RAISE THE CIGS IN THE AFTN WED. WAVES OF LOW PRESSURE THEN
CONTINUE TO MOVE W-E ALONG THE WAVY FRONT WED NIGHT AND THURSDAY
IN ADVANCE OF SYSTEM WHICH WILL WRAP UP OVER THE MIDWEST/OH VALLEY
AND MOVE THROUGH LATE THURS/EARLY FRI.
.OUTLOOK...
THU...EARLY AM LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS NORTH.
FRI...RAIN/LOW CIGS POSS...ESP EARLY. SHRA POSS NW PM.
SAT-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
104 PM CDT TUE APR 9 2013
.UPDATE...
THE 18Z FWD SOUNDING THAT WAS LAUNCHED HAS DATA QUALITY PROBLEMS
AND SHOULD BE DISREGARDED FOR THE MOST PART. THE CAP IS STILL IN
PLACE ACROSS THE REGION AND WE WILL INSTEAD BE USING ACARS
SOUNDINGS FOR DATA THROUGH THE AFTERNOON HOURS. THE INSTRUMENT
THAT WAS USED FOR THE 18Z FWD SOUNDING IS A TEST INSTRUMENT AND
THIS WAS THE FIRST UPPER AIR LAUNCH WITH THIS NEW RADIOSONDE.
82/JLD
&&
.AVIATION...
PERSISTENCE WILL BE THE KEY REGARDING SURFACE WINDS TODAY AS
STRONG LOW LEVEL FLOW CONTINUES AHEAD OF THE STORM SYSTEM
CURRENTLY OVER THE 4-CORNERS REGION. WILL MAINTAIN THE FORECAST OF
SUSTAINED WINDS IN THE 15-20KT RANGE UP UNTIL THE PASSAGE OF THE
FRONT TONIGHT. MEANWHILE...STRATUS WITHIN THE 50+ KT LOW LEVEL JET
CONTINUES TO STREAM OVERHEAD. BREAKS IN THE CLOUD FIELD CAN BE
SEEN ON 11-3.9 MICRON IMAGERY SO CIGS WILL LIKELY VARY BETWEEN VFR
AND MVFR AT ALL SITES THIS MORNING.
FOR TONIGHT...A STRONG COLD FRONT PROJECTED TO ADVANCE
SOUTHEASTWARD ACROSS NORTH TEXAS WILL LIKELY BE ACCOMPANIED BY
A ROUND OF SHOWERS AND STORMS. A BLEND OF THE LATEST MODEL GUIDANCE
INDICATES FROPA IN THE METROPLEX 08-09Z AND CLOSER TO 12Z AT KACT.
STRONG NORTH-NORTHWESTERLY WINDS WILL OCCUR WEDNESDAY FOLLOWING
THE PASSAGE OF THE FRONT...WITH MVFR CONDITIONS LINGERING THROUGH
MUCH OF THE DAY.
30
&&
.PREV UPDATE...
.UPDATE...
AT 11 AM THIS MORNING...A LARGE UPPER LEVEL LOW WAS MOVING
ACROSS NORTHERN NEW MEXICO WITH THE BASE OF THE UPPER LEVEL TROUGH
SWINGING DOWN INTO EXTREME NORTHERN MEXICO. AT THE SURFACE...A
COLD FRONT WAS MOVING AHEAD OF SCHEDULE THROUGH THE TEXAS
PANHANDLE WITH A DRYLINE EXTENDING DOWN THROUGH FAR WEST TEXAS.
THE COLD FRONT WAS LOCATED JUST NORTH OF PLAINVIEW TEXAS EXTENDING
BACK TO THE NORTHEAST TO WOODWARD OKLAHOMA AND MEDICINE LODGE
KANSAS. TEMPERATURES BEHIND THE FRONT ARE IN THE 30S WITH WINDS
GUSTING AROUND 40 MPH AT SEVERAL LOCATIONS. THESE CONDITIONS ARE
QUICKLY ACCELERATING THE FRONT FASTER THAN PREVIOUSLY THOUGHT BUT
THE 12Z NAM AND RAP HAVE PICKED UP ON THE FASTER FRONTAL LOCATION.
UNFORTUNATELY THE 12Z GFS IS STILL MUCH TOO SLOW AND HAD TO BE
DISCOUNTED FOR MUCH OF THE UPDATE.
BY MID AFTERNOON THE DRYLINE WILL BE LOCATED ALONG THE WESTERN
BORDER OF THE CWA WITH THE COLD FRONT ALREADY MOVING ACROSS
SOUTHWESTERN OKLAHOMA AND NORTHWEST TEXAS. THE COLD FRONT WILL
QUICKLY OVERTAKE THE DRYLINE BY THE LATE AFTERNOON/EARLY EVENING
HOURS JUST NORTHWEST OF THE AREA AND WILL START TO ENTER OUR
NORTHWESTERN COUNTIES BY 10 PM. WITH THIS FASTER TIMING...THIS
FURTHER LIMITS THE POTENTIAL FOR STORMS TO DEVELOP ON THE DRYLINE
THIS AFTERNOON. HAVE UPDATED ALL APPROPRIATE FORECAST PARAMETERS
THROUGH TOMORROW TO REFLECT THE LOCATION OF THE DRYLINE AND THE
FASTER FRONTAL ARRIVAL AND MOVEMENT.
REGARDING THE SEVERE WEATHER POTENTIAL FOR LATER TODAY AND
TONIGHT. UNCERTAINTY STILL REMAINS ON IF STORMS WILL DEVELOP ON
THE DRYLINE NEAR OUR WESTERN AND/OR NORTHWESTERN COUNTIES. THE 12Z
FWD SOUNDING THIS MORNING SHOWS A VERY LARGE CAP STILL IN PLACE
AND MODIFYING THE SOUNDING FOR AFTERNOON TEMPERATURES IN THE MID
80S STILL REVEALS A STRONG CAP OVER -100 J/KG. WE WILL BE DOING A
SPECIAL 18Z SOUNDING THIS AFTERNOON AND WILL SEE HOW THE CAP HAS
CHANGED SINCE 12Z THIS MORNING. WE CONTINUE TO MAINTAIN THE
THINKING THAT THE CAP WILL HOLD OVER THE AREA THIS AFTERNOON BUT
WE DO NOT DISCOUNT THAT THERE IS A NARROW WINDOW AROUND 5-7 PM
DURING WHICH THE CAP COULD BE BREACHED BEFORE THE FRONT TAKES OVER
THE DRYLINE. HOWEVER...WITH THE MAIN UPPER LEVEL LIFT STILL WEST
OF THE REGION AT THAT TIME...IT WILL LIKELY BE VERY DIFFICULT TO
DEVELOP ANY STORMS ALONG THE DRYLINE. BUT ANY STORM THAT IS ABLE
TO DEVELOP ON THE DRYLINE WOULD HAVE A THREAT FOR LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY A TORNADO. THESE STORMS WOULD
BE MOVING TO THE NORTHEAST AND WOULD LIKELY ONLY POSE A THREAT TO
A FEW OF OUR NORTHWESTERN COUNTIES FROM STEPHENS TO MONTAGUE
COUNTY.
AS THE COLD FRONT MOVES THROUGH THE REGION OVERNIGHT...A LINE OF
STORMS WILL LIKELY OCCUR ALONG THE LEADING EDGE WITH A THREAT FOR
SCATTERED SEVERE STORMS ALONG THE LINE...MAINLY FROM 10 PM THROUGH
6 AM. IN ADDITION...CONVECTION WILL LIKELY ALSO BE OCCURRING BEHIND
THE LEADING EDGE OF THE FRONT AND SOUNDINGS STILL SUPPORT THE
POTENTIAL FOR HAIL WITH THESE STORMS IF THEY CAN REACH THROUGH THE
REDEVELOPING CAP OVERNIGHT.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE APR 9 2013/
ANOTHER MOSTLY CLOUDY...BREEZY AND WARM DAY IS IN STORE FOR NORTH
TEXAS TODAY AHEAD OF AN APPROACHING UPPER LEVEL STORM SYSTEM AND
ASSOCIATED COLD FRONT. AS OF 3 AM THE COLD FRONT HAD ALREADY MOVED
INTO SOUTHEAST COLORADO AND NORTHWEST KANSAS WITH WIND GUSTS
BEHIND THE FRONT AS HIGH AS 58 MPH. THE AIR BEHIND THE FRONT IS
VERY COLD FOR EARLY APRIL WITH TEENS AND 20S ACROSS PARTS OF
WYOMING AND NEBRASKA. THE COLD FRONT WILL CONTINUE TO SURGE SOUTH
TODAY BUT SHOULD SLOW A BIT DUE TO BOUNDARY LAYER MIXING ON THE
LEADING EDGE. THE DRY LINE WILL ALSO MIX EASTWARD THROUGH THE DAY
AND SHOULD APPROACH THE EXTREME WESTERN ZONES BEFORE SUNSET. THE
COLD FRONT SHOULD OVERTAKE THE DRYLINE DURING EVENING AND MOVE
QUICKLY ACROSS NORTH TEXAS OVERNIGHT/WEDNESDAY MORNING.
THE MOST LIKELY SCENARIO WHERE THUNDERSTORMS ARE CONCERNED IS
THAT THE STRONG CAP THAT IS CURRENTLY IN PLACE ACROSS THE REGION
WILL WEAKEN THROUGH THE DAY AS LARGE SCALE LIFT INCREASES. THE CAP
MAY BREAK IN THE EXTREME NORTHWEST ZONES JUST BEFORE SUNSET WITH
RAPID THUNDERSTORM DEVELOPMENT POSSIBLE. HOWEVER...CONFIDENCE IS
LOW THAT THE CAP WILL BREAK BEFORE THE COLD FRONT ARRIVES THIS
EVENING...AND THIS IS SUPPORTED BY THE 4 KM WRF AND TTU WRF.
THEREFORE...WILL LEAVE ONLY LOW LATE AFTERNOON POPS IN THE EXTREME
NORTHWEST ZONES ON THE OUTSIDE CHANCE THAT THE CAP BREAKS. IF ANY
STORMS DO DEVELOP BEFORE SUNSET...THEY WILL HAVE SUFFICIENT
INSTABILITY AND SHEAR TO SUPPORT SUPERCELL FORMATION.
THE CAP SHOULD BREAK BY LATE EVENING AS THE COLD FRONT BEGINS TO
MOVE THROUGH THE REGION. STORMS THAT DEVELOP ALONG OR JUST AHEAD
OF THE COLD FRONT WILL HAVE A GOOD CHANCE OF BECOMING SEVERE WITH
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CAN NOT BE
RULED OUT BUT FEEL THE TIME OF DAY AND SPEED OF THE FRONT MAY
LIMIT THE POTENTIAL. THE HIGH RES MODELS CONTINUE TO SHOW THE
FRONT MOVING QUICKLY THROUGH THE REGION WITH POST-FRONTAL...MAINLY
NON SEVERE...THUNDERSTORMS OVERNIGHT/WEDNESDAY MORNING. THE GOOD
NEWS IS THAT THE WINDOW SEVERE WEATHER IN ANY ONE AREA SHOULD BE SMALL
WITH A MUCH LARGER WINDOW OF TIME FOR MUCH NEEDED POST-FRONTAL
PRECIPITATION. ALL SHOWERS AND STORMS SHOULD END FROM WEST TO EAST
ON WEDNESDAY AS MUCH DRIER AND COLDER AIR MOVES IN.
THE NEXT CHALLENGE WITH THIS FORECAST WILL BE THE POST-FRONTAL
TEMPERATURES. THE NAM CONTINUES TO BE THE COLDEST OF THE SOLUTIONS
AND BASED ON LATEST SURFACE ANALYSIS...IT SEEMS TO HAVE THE BEST
HANDLE ON THE COLD AIR. EXPECT AFTERNOON HIGHS WEDNESDAY TO ONLY
REACH THE LOWER 50S IN THE NORTHWEST ZONES BUT THE SOUTHEAST SHOULD
STILL BE IN THE UPPER 60S TO LOWER 70S. CLEARING SKIES AND
DECREASING WIND SPEEDS WEDNESDAY NIGHT WILL ALLOW TEMPS TO FALL
INTO THE 30S TO LOWER 40S. IT APPEARS THAT ONLY THE NORTHWEST
ZONES WILL APPROACH FREEZING BRIEFLY AROUND SUNRISE THURSDAY
MORNING. TEMPERATURES WILL BEGIN TO REBOUND ON THURSDAY AFTERNOON AS
SURFACE HIGH PRESSURE MOVES TO THE EAST. THE WARMING TREND WILL
CONTINUE THROUGH THE WEEKEND AS LOW LEVEL MOISTURE RETURNS TO THE
REGION. WEST TO SOUTHWEST FLOW ALOFT AND A PERSISTENT LEE TROUGH
WILL KEEP WARM AND RAIN-FREE WEATHER ACROSS NORTH TEXAS THROUGH
EARLY NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 50 57 38 62 41 / 90 60 10 0 0
WACO, TX 60 62 39 64 41 / 90 70 10 5 0
PARIS, TX 60 62 37 57 39 / 90 70 20 5 0
DENTON, TX 47 55 35 61 36 / 90 60 10 0 0
MCKINNEY, TX 52 58 35 59 38 / 90 60 10 5 0
DALLAS, TX 53 59 39 61 42 / 90 70 10 0 0
TERRELL, TX 59 61 35 60 40 / 90 70 10 5 0
CORSICANA, TX 63 65 35 64 41 / 70 80 10 5 0
TEMPLE, TX 63 64 39 64 42 / 80 80 10 5 0
MINERAL WELLS, TX 42 51 33 63 38 / 90 40 10 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
100 PM CDT TUE APR 9 2013
.UPDATE...
ANOTHER UPDATE AS THE COLD FRONT CONTINUES PROGRESSING TO THE
SOUTH WELL AHEAD OF SCHEDULE. NOT MUCH INDICATION YET OF SLOWING
ALTHOUGH THE LATEST RAP CONTINUES TO HOLD FRONT FROM PASSING
THROUGH ALL OF THE SOUTHWESTERN COUNTIES. WE WILL SEE AND UPDATE
AGAIN AS NEEDED. ADDED PATCHY BLOWING DUST THIS TIME...EXPECT TO
SEE VISIBILITY BRIEFLY DROP AS LOW AS ONE TO THREE MILES JUST
BEHIND THE FRONT THEN GRADUALLY IMPROVING. WE ALSO INCREASED THE
MENTION OF THUNDER INTO THE CHANCE CATEGORY OVER TE NORTHERN
ROLLING PLAINS...THOUGH VEERED LOW LEVEL WINDS SHOULD ALLOW
MOISTURE TO CLEAR OUT ENOUGH TO THE EAST TO KEEP SEVERE RISK JUST
BELOW MENTIONABLE LEVELS. LOTS OF ISSUES TO FOLLOW TONIGHT THAT
HAVE YET TO BE FULLY RESOLVED REGARDING PRECIPITATION
CHANCES...POSSIBILITY FOR FREEZING PRECIPITATION...AND ALSO FOR A
FREEZE OVER THE NORTHERN ROLLING PLAINS. RMCQUEEN
&&
.AVIATION...
ADJUSTMENTS MADE FOR MUCH EARLIER FRONTAL PASSAGE...ADDED BLOWING
DUST AT KLBB...VICINITY SHOWERS AT KCDS EARLY AND MENTION OF
DRIZZLE AND LIGHT FOG LATER...AND ALSO LOWER CEILINGS DEVELOPING
ESPECIALLY AT KCDS. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 1004 AM CDT TUE APR 9 2013/
UPDATE...
THE COLD FRONT HAS PASSED THROUGH FRIONA...DIMMITT...AND HAPPY
ALREADY QUITE A BIT AHEAD OF SCHEDULE. SHORT TERM SURFACE PRESSURE
RISES HAVE WEAKENED BUT THE FRONT WAS CONTINUING TO ADVANCE ON
LARGER SCALE PUSHES. WE HAVE ACCEPTED THE LATEST RAP RUN FOR NOW
AND UPDATED FOR THE FRONT TO WORK THROUGH MOST OF THE NORTHERN
AREA BEFORE STALLING AROUND MIDDAY. TEMPERATURES LOWERED ACROSS
NORTHERN ZONES AND WARMED SLIGHTLY SOME SOUTHERN AREAS. THE FRONT
MAY BE ABLE TO CATCH UP TO THE MOISTURE LYING OVER THE NORTHERN
ROLLING PLAINS AND GIVE A VALID LOW CHANCE FOR THUNDER. WE WILL
STUDY FURTHER FOR SEVERE CHANCES AS WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 623 AM CDT TUE APR 9 2013/
AVIATION...
MVFR CIGS DEVELOPING IN MOIST AIR THAT HAS MOVED BACK INTO THE
FCST AREA WILL PERSIST UNTIL LOW LEVEL WINDS BEGIN TO VEER TO THE
SW AND INCREASE IN SPEED. THAT IS LIKELY TO OCCUR BY 14Z AT KLBB
AND 17Z AT KCDS. AFTERWARDS...GUSTY SW WINDS EXPECTED THROUGH THE
DAY FOLLOWED BY GUSTY NORTH WINDS BEHIND A STRONG COLD FRONT THAT
WILL MOVE THROUGH THE FCST AREA THIS EVENING. POTENTIAL FOR SOME
LIGHT SHOWERS OVERNIGHT WITH THE APPROACH OF AN UPPER LEVEL
DISTURBANCE FAVORS KCDS OVER KLBB.
PREV DISCUSSION... /ISSUED 319 AM CDT TUE APR 9 2013/
SHORT TERM...
RATHER DYNAMIC PATTERN SETTING UP FOR THE NEXT 24 HOURS AS A STRONG
UPPER LOW EJECTS FROM THE 4-CORNERS TO THE CNTL PLAINS WHILE THE
PARENT TROUGH MOVES FROM WEST TO EAST TOWARD THE FCST AREA.
INITIALLY A MID LEVEL JET WILL PUNCH ACROSS THE AREA AS IT ROTATES
NEWD WITH THE UPPER LOW. PROGGED MAGNITUDE OF THIS JET HAS WEAKENED
RELATIVE TO RECENT MODEL RUNS WITH 500 MB SPEEDS OF AROUND 90 KTS
AND 700 MB ABOUT HALF THAT. MIXING WILL BE FAIRLY EFFICIENT DESPITE
COOLER TEMPERATURES THAN THE LAST FEW DAYS COURTESY OF LOWERING
HEIGHTS AND THICKNESSES WITH THE ADVANCING UPPER TROUGH. THIS SHOULD
RESULT IN WINDS MOSTLY IN A RANGE OF 20 TO 30 MPH...PERIODICALLY
SLIGHTLY STRONGER UP ON THE CAPROCK...ATTM NOT EXPECTED TO BE QUITE
STRONG ENOUGH TO JUSTIFY A WIND ADVISORY. THIS MID LEVEL JET MAX
WILL HELP QUICKLY MIX THE DRYLINE EWD THROUGH THE FCST AREA WITH LOW
DEW POINT AIR MOVING IN BEHIND IT AND EFFECTIVELY KILLING ANY PRECIP
CHANCES DURING THE AFTN.
THAT LOOKS TO CHANGE OVERNIGHT AS THE UPPER TROUGH CONTINUES TO
ADVANCE TOWARD THE AREA. MID LEVEL LIFT AND MOISTURE ASSOCIATED WITH
THE TROUGH LIKELY SUFFICIENT TO PRODUCE SOME ELEVATED SHOWERS ACROSS
MAINLY THE NRN HALF OF THE FCST AREA WHERE THAT COMBINATION WILL BE
GREATEST. STILL DO NOT EXPECT ANYTHING MORE THAN A SCATTERED NATURE
TO THE SHOWERS AND 30 TO 40 PCT POPS THERE LOOK REASONABLE. FCST
FURTHER COMPLICATED BY A STRONG COLD FRONT THAT WILL MOVE QUICKLY
THROUGH THE FCST AREA DURING THE EVENING HOURS. THIS FRONT WILL
USHER IN VERY COLD AIR THE STRENGTH OF WHICH IS INDICATED BY
TEMPERATURES IN THE TEENS AND 20S ACROSS SERN WYOMING AND NERN
COLORADO PENETRATING SWD DOWN THE LEE OF THE FRONT RANGE. THAT FRONT
IS JUST SOUTH OF A TRINIDAD COLO TO SPRINGFIELD COLO TO COLBY KS
LINE AT 08Z. THIS IS JUST A BIT AHEAD OF WRF-NAM POSITIONING. THE
FRONT WILL MOVE INTO THE TEXAS PANHANDLE THIS MORNING WHERE IT
SHOULD STALL IN THE FACE OF WARM TEMPS AND SW WINDS...BUT THEN
QUICKLY ACCELERATE SWD LATE THIS AFTN OR EARLY THIS EVENING. COLD AIR
THAT COMES IN BEHIND THE FRONT MAY BE COLD ENOUGH TO PRODUCE SOME
FROZEN PRECIP BEFORE PRECIP COMES TO AN END TONIGHT...AND WILL
MAINTAIN THAT WORDING IN THE FCST WITH ONLY MINOR ADJUSTMENTS TO
AREAL EXTENT. PRESSURE RISES BEHIND THE FRONT LIKELY TO BE FAIRLY
STRONG WITH SOME POTENTIAL FOR WIND ADVISORY SPEEDS FOR A TIME
OVERNIGHT.
LONG TERM...
PER THE NAM...GFS AND CMC SOLUTIONS...THE MEAN TROUGH OF THE BROAD UA
LOW ACROSS THE CENTRAL PLAINS WILL CONTINUE TO SWING EAST ACROSS THE
ROLLING PLAINS TOMORROW MORNING...WHILST THE BEST PRECIP WILL
SHIFT EAST OF THE CWA THUS COINCIDING WITH BEST LARGE SCALE ASCENT.
THE ECMWF IS A BIT OF AN OUTLIER AS IT IS SLIGHTLY SLOWER THAN THE
OTHERS...AND THUS EXHIBITING PRECIP LINGERING THROUGH TOMORROW
AFTN. WILL LEAN TOWARDS THE FORMER SOLUTIONS ATTM...GIVEN BETTER
CONSISTENCY. A 1020+ MB SFC RIDGE WELL NORTH OF THE REGION WILL BE
THE DRIVING FORCE BEHIND THE COLD FRONT...SET TO INTRUDE THE
REGION TONIGHT AND BE LOCATED ACROSS THE PERMIAN BASIN BY TOMORROW
MORNING. INITIAL PRESSURE RISES OF 12 MB/3 HR WILL HAVE RELAXED
SUBSTANTIAL AT THE START OF THE EXTENDED PERIOD...HOWEVER 850 MB
TEMPS HOVERING NEAR THE FREEZING MARK DURING THE DAY TOMORROW
SUGGEST TEMPS IN THE 40S AND 50S...OR SOME 15-20 DEGREES BELOW
NORM.
THE AFOREMENTIONED SFC RIDGE WILL SHIFT SOUTH TO ACROSS THE CWA
TOMORROW NIGHT THUS PROMOTING LIGHT AND VARIABLE WINDS...IN ADDITION
TO MAINTAINING 850 MB TEMPS NEAR/SLIGHTLY BELOW FREEZING. IT IS NO
WONDER MOS GUIDANCE HINTS AT OVERNIGHT TEMPS RIGHT AT OR BELOW
FREEZING ACROSS THE ENTIRE CWA. SINCE WE ARE JUST ENTERING THE
GROWING SEASON THIS OF COURSE RAISES CONCERN. WILL ADD STRONG
WORDING TO THE HAZARDOUS WEATHER OUTLOOK ATTM...HOWEVER A
FREEZE WATCH/WARNING MAY BE REQUIRED AND WILL LET LATER SHIFTS
ANALYZE FUTURE MODEL RUNS TO SEE IF THIS IS INDEED WARRANTED.
BROAD CYCLONIC FLOW ALOFT WILL BECOME NWRLY BY THURSDAY...WHILST SFC
RIDGING TRANSLATES AWAY FROM THE REGION...AND THE DEVELOPMENT OF SFC
LEE TROUGHING ENCOURAGES A RETURN TO SRLY FLOW AND THUS WARMER
TEMPS /UPPER 60S TO LOW TO MID 70S BY FRIDAY/. THEREAFTER...A FRONT IS
PROGGED TO MOVE ACROSS MOST OF THE CWA FRIDAY NIGHT /PRODUCING THE
DEVELOPMENT OF MID-LEVEL CLOUDINESS/...AHEAD OF AN EMBEDDED
DISTURBANCE IN THE FLOW ALOFT...SET TO MOVE ACROSS THE REGION
FRIDAY NIGHT. MODELS CONTINUE TO SHOW LIGHT QPF SIGNALS MAINLY ACROSS
THE NERN ZONES DURING THE SAID TIME PERIOD...AND HAVE ELECTED TO
INCREASE POPS TO 14 PERCENT...JUST BELOW MENTIONABLE LEVELS ATTM.
SFC LEE CYCLOGENESIS WILL RESUME FOR THE WEEKEND THROUGH EARLY NEXT
WEEK...LEADING TOWARDS TEMPS WARMING INTO THE 70S AND 80S. AS
SUCH...A DRYLINE WILL SHARPEN AND LINGER ACROSS THE FA. LONG TERM
SOLUTIONS SHOW RATHER PROGRESSIVE FLOW ACROSS THE NRN CONUS...AND
ONE OF THOSE DISTURBANCES WILL SEND A BACKDOOR COLD FRONT TOWARDS
THE SERN TEXAS PANHANDLE MONDAY. COULD SEE PRECIP DEVELOP ALONG THE
DRYLINE AND COLD FRONTAL BOUNDARY INTERSECTION ACROSS THE ROLLING
PLAINS...BUT HAVE KEPT POPS SILENT AND WILL AWAIT TO SEE IF THIS
PATTERN AND ASSOCIATED MESO-SCALE FEATURES ARE CONSISTENT FROM RUN TO
RUN.
FIRE WEATHER...
MARGINALLY CRITICAL CONDITIONS POSSIBLE FOR A TIME THIS AFTERNOON
WITH THE MAIN LIMITING FACTOR BEING RELATIVE HUMIDITY. HAVE LOWERED
FCST RH A LITTLE THIS MORNING WITH EXPECTATION OF SLIGHTLY WARMER
TEMPS THAN PREVIOUSLY EXPECTED. THAT WILL BRING MINIMUM RH VALUES
NEAR 15 PCT FOR MUCH OF THE AREA WHILE WINDS SHOULD FAIRLY EASILY
EXCEED 20 MPH AT THE 20-FOOT LEVEL. SOME QUESTION TOO OF HOW MUCH
THOSE TWO WILL OVERLAP WITH POSSIBILITY OF THE WIND SPEEDS MAXING
OUT A LITTLE AHEAD OF THE RH BOTTOM. SHOULD SEE SOME PERIODS OF
CRITICAL CONDITIONS AS RH FLIRTS WITH THE 15 PCT CRITERIA...BUT
PRETTY UNCERTAIN WITH RESPECT TO DURATION. GIVEN UNCERTAINTIES AS
WELL AS GOOD RH RECOVERY FOR ALMOST ALL OF THE FCST AREA THIS
MORNING WILL OPT FOR A FIRE DANGER STATEMENT OVER A RED FLAG WARNING
ATTM.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 20 48 25 64 35 / 30 0 0 0 0
TULIA 24 49 24 63 36 / 30 10 0 0 0
PLAINVIEW 26 51 25 63 38 / 30 10 0 0 0
LEVELLAND 26 53 27 66 40 / 20 0 0 0 0
LUBBOCK 30 53 27 66 41 / 20 10 0 0 0
DENVER CITY 29 55 27 68 44 / 10 0 0 0 0
BROWNFIELD 30 55 27 67 42 / 10 0 0 0 0
CHILDRESS 33 51 27 65 39 / 40 10 0 0 0
SPUR 35 55 29 66 40 / 20 10 0 0 0
ASPERMONT 37 55 30 66 42 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1125 AM CDT TUE APR 9 2013
.UPDATE...
AT 11 AM THIS MORNING...A LARGE UPPER LEVEL LOW WAS MOVING
ACROSS NORTHERN NEW MEXICO WITH THE BASE OF THE UPPER LEVEL TROUGH
SWINGING DOWN INTO EXTREME NORTHERN MEXICO. AT THE SURFACE...A
COLD FRONT WAS MOVING AHEAD OF SCHEDULE THROUGH THE TEXAS
PANHANDLE WITH A DRYLINE EXTENDING DOWN THROUGH FAR WEST TEXAS.
THE COLD FRONT WAS LOCATED JUST NORTH OF PLAINVIEW TEXAS EXTENDING
BACK TO THE NORTHEAST TO WOODWARD OKLAHOMA AND MEDICINE LODGE
KANSAS. TEMPERATURES BEHIND THE FRONT ARE IN THE 30S WITH WINDS
GUSTING AROUND 40 MPH AT SEVERAL LOCATIONS. THESE CONDITIONS ARE
QUICKLY ACCELERATING THE FRONT FASTER THAN PREVIOUSLY THOUGHT BUT
THE 12Z NAM AND RAP HAVE PICKED UP ON THE FASTER FRONTAL LOCATION.
UNFORTUNATELY THE 12Z GFS IS STILL MUCH TOO SLOW AND HAD TO BE
DISCOUNTED FOR MUCH OF THE UPDATE.
BY MID AFTERNOON THE DRYLINE WILL BE LOCATED ALONG THE WESTERN
BORDER OF THE CWA WITH THE COLD FRONT ALREADY MOVING ACROSS
SOUTHWESTERN OKLAHOMA AND NORTHWEST TEXAS. THE COLD FRONT WILL
QUICKLY OVERTAKE THE DRYLINE BY THE LATE AFTERNOON/EARLY EVENING
HOURS JUST NORTHWEST OF THE AREA AND WILL START TO ENTER OUR
NORTHWESTERN COUNTIES BY 10 PM. WITH THIS FASTER TIMING...THIS
FURTHER LIMITS THE POTENTIAL FOR STORMS TO DEVELOP ON THE DRYLINE
THIS AFTERNOON. HAVE UPDATED ALL APPROPRIATE FORECAST PARAMETERS
THROUGH TOMORROW TO REFLECT THE LOCATION OF THE DRYLINE AND THE
FASTER FRONTAL ARRIVAL AND MOVEMENT.
REGARDING THE SEVERE WEATHER POTENTIAL FOR LATER TODAY AND
TONIGHT. UNCERTAINTY STILL REMAINS ON IF STORMS WILL DEVELOP ON
THE DRYLINE NEAR OUR WESTERN AND/OR NORTHWESTERN COUNTIES. THE 12Z
FWD SOUNDING THIS MORNING SHOWS A VERY LARGE CAP STILL IN PLACE
AND MODIFYING THE SOUNDING FOR AFTERNOON TEMPERATURES IN THE MID
80S STILL REVEALS A STRONG CAP OVER -100 J/KG. WE WILL BE DOING A
SPECIAL 18Z SOUNDING THIS AFTERNOON AND WILL SEE HOW THE CAP HAS
CHANGED SINCE 12Z THIS MORNING. WE CONTINUE TO MAINTAIN THE
THINKING THAT THE CAP WILL HOLD OVER THE AREA THIS AFTERNOON BUT
WE DO NOT DISCOUNT THAT THERE IS A NARROW WINDOW AROUND 5-7 PM
DURING WHICH THE CAP COULD BE BREACHED BEFORE THE FRONT TAKES OVER
THE DRYLINE. HOWEVER...WITH THE MAIN UPPER LEVEL LIFT STILL WEST
OF THE REGION AT THAT TIME...IT WILL LIKELY BE VERY DIFFICULT TO
DEVELOP ANY STORMS ALONG THE DRYLINE. BUT ANY STORM THAT IS ABLE
TO DEVELOP ON THE DRYLINE WOULD HAVE A THREAT FOR LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY A TORNADO. THESE STORMS WOULD
BE MOVING TO THE NORTHEAST AND WOULD LIKELY ONLY POSE A THREAT TO
A FEW OF OUR NORTHWESTERN COUNTIES FROM STEPHENS TO MONTAGUE
COUNTY.
AS THE COLD FRONT MOVES THROUGH THE REGION OVERNIGHT...A LINE OF
STORMS WILL LIKELY OCCUR ALONG THE LEADING EDGE WITH A THREAT FOR
SCATTERED SEVERE STORMS ALONG THE LINE...MAINLY FROM 10 PM THROUGH
6 AM. IN ADDITION...CONVECTION WILL LIKELY ALSO BE OCCURRING BEHIND
THE LEADING EDGE OF THE FRONT AND SOUNDINGS STILL SUPPORT THE
POTENTIAL FOR HAIL WITH THESE STORMS IF THEY CAN REACH THROUGH THE
REDEVELOPING CAP OVERNIGHT.
82/JLD
&&
.AVIATION...
PERSISTENCE WILL BE THE KEY REGARDING SURFACE WINDS TODAY AS
STRONG LOW LEVEL FLOW CONTINUES AHEAD OF THE STORM SYSTEM
CURRENTLY OVER THE 4-CORNERS REGION. WILL MAINTAIN THE FORECAST OF
SUSTAINED WINDS IN THE 15-20KT RANGE UP UNTIL THE PASSAGE OF THE
FRONT TONIGHT. MEANWHILE...STRATUS WITHIN THE 50+ KT LOW LEVEL JET
CONTINUES TO STREAM OVERHEAD. BREAKS IN THE CLOUD FIELD CAN BE
SEEN ON 11-3.9 MICRON IMAGERY SO CIGS WILL LIKELY VARY BETWEEN VFR
AND MVFR AT ALL SITES THIS MORNING.
FOR TONIGHT...A STRONG COLD FRONT PROJECTED TO ADVANCE
SOUTHEASTWARD ACROSS NORTH TEXAS WILL LIKELY BE ACCOMPANIED BY
A ROUND OF SHOWERS AND STORMS. A BLEND OF THE LATEST MODEL GUIDANCE
INDICATES FROPA IN THE METROPLEX 08-09Z AND CLOSER TO 12Z AT KACT.
STRONG NORTH-NORTHWESTERLY WINDS WILL OCCUR WEDNESDAY FOLLOWING
THE PASSAGE OF THE FRONT...WITH MVFR CONDITIONS LINGERING THROUGH
MUCH OF THE DAY.
30
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE APR 9 2013/
ANOTHER MOSTLY CLOUDY...BREEZY AND WARM DAY IS IN STORE FOR NORTH
TEXAS TODAY AHEAD OF AN APPROACHING UPPER LEVEL STORM SYSTEM AND
ASSOCIATED COLD FRONT. AS OF 3 AM THE COLD FRONT HAD ALREADY MOVED
INTO SOUTHEAST COLORADO AND NORTHWEST KANSAS WITH WIND GUSTS
BEHIND THE FRONT AS HIGH AS 58 MPH. THE AIR BEHIND THE FRONT IS
VERY COLD FOR EARLY APRIL WITH TEENS AND 20S ACROSS PARTS OF
WYOMING AND NEBRASKA. THE COLD FRONT WILL CONTINUE TO SURGE SOUTH
TODAY BUT SHOULD SLOW A BIT DUE TO BOUNDARY LAYER MIXING ON THE
LEADING EDGE. THE DRY LINE WILL ALSO MIX EASTWARD THROUGH THE DAY
AND SHOULD APPROACH THE EXTREME WESTERN ZONES BEFORE SUNSET. THE
COLD FRONT SHOULD OVERTAKE THE DRYLINE DURING EVENING AND MOVE
QUICKLY ACROSS NORTH TEXAS OVERNIGHT/WEDNESDAY MORNING.
THE MOST LIKELY SCENARIO WHERE THUNDERSTORMS ARE CONCERNED IS
THAT THE STRONG CAP THAT IS CURRENTLY IN PLACE ACROSS THE REGION
WILL WEAKEN THROUGH THE DAY AS LARGE SCALE LIFT INCREASES. THE CAP
MAY BREAK IN THE EXTREME NORTHWEST ZONES JUST BEFORE SUNSET WITH
RAPID THUNDERSTORM DEVELOPMENT POSSIBLE. HOWEVER...CONFIDENCE IS
LOW THAT THE CAP WILL BREAK BEFORE THE COLD FRONT ARRIVES THIS
EVENING...AND THIS IS SUPPORTED BY THE 4 KM WRF AND TTU WRF.
THEREFORE...WILL LEAVE ONLY LOW LATE AFTERNOON POPS IN THE EXTREME
NORTHWEST ZONES ON THE OUTSIDE CHANCE THAT THE CAP BREAKS. IF ANY
STORMS DO DEVELOP BEFORE SUNSET...THEY WILL HAVE SUFFICIENT
INSTABILITY AND SHEAR TO SUPPORT SUPERCELL FORMATION.
THE CAP SHOULD BREAK BY LATE EVENING AS THE COLD FRONT BEGINS TO
MOVE THROUGH THE REGION. STORMS THAT DEVELOP ALONG OR JUST AHEAD
OF THE COLD FRONT WILL HAVE A GOOD CHANCE OF BECOMING SEVERE WITH
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CAN NOT BE
RULED OUT BUT FEEL THE TIME OF DAY AND SPEED OF THE FRONT MAY
LIMIT THE POTENTIAL. THE HIGH RES MODELS CONTINUE TO SHOW THE
FRONT MOVING QUICKLY THROUGH THE REGION WITH POST-FRONTAL...MAINLY
NON SEVERE...THUNDERSTORMS OVERNIGHT/WEDNESDAY MORNING. THE GOOD
NEWS IS THAT THE WINDOW SEVERE WEATHER IN ANY ONE AREA SHOULD BE SMALL
WITH A MUCH LARGER WINDOW OF TIME FOR MUCH NEEDED POST-FRONTAL
PRECIPITATION. ALL SHOWERS AND STORMS SHOULD END FROM WEST TO EAST
ON WEDNESDAY AS MUCH DRIER AND COLDER AIR MOVES IN.
THE NEXT CHALLENGE WITH THIS FORECAST WILL BE THE POST-FRONTAL
TEMPERATURES. THE NAM CONTINUES TO BE THE COLDEST OF THE SOLUTIONS
AND BASED ON LATEST SURFACE ANALYSIS...IT SEEMS TO HAVE THE BEST
HANDLE ON THE COLD AIR. EXPECT AFTERNOON HIGHS WEDNESDAY TO ONLY
REACH THE LOWER 50S IN THE NORTHWEST ZONES BUT THE SOUTHEAST SHOULD
STILL BE IN THE UPPER 60S TO LOWER 70S. CLEARING SKIES AND
DECREASING WIND SPEEDS WEDNESDAY NIGHT WILL ALLOW TEMPS TO FALL
INTO THE 30S TO LOWER 40S. IT APPEARS THAT ONLY THE NORTHWEST
ZONES WILL APPROACH FREEZING BRIEFLY AROUND SUNRISE THURSDAY
MORNING. TEMPERATURES WILL BEGIN TO REBOUND ON THURSDAY AFTERNOON AS
SURFACE HIGH PRESSURE MOVES TO THE EAST. THE WARMING TREND WILL
CONTINUE THROUGH THE WEEKEND AS LOW LEVEL MOISTURE RETURNS TO THE
REGION. WEST TO SOUTHWEST FLOW ALOFT AND A PERSISTENT LEE TROUGH
WILL KEEP WARM AND RAIN-FREE WEATHER ACROSS NORTH TEXAS THROUGH
EARLY NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 82 50 57 38 62 / 10 90 60 10 0
WACO, TX 84 60 62 39 64 / 10 90 70 10 5
PARIS, TX 82 60 62 37 57 / 10 90 70 20 5
DENTON, TX 82 47 55 35 61 / 10 90 60 10 0
MCKINNEY, TX 82 52 58 35 59 / 10 90 60 10 5
DALLAS, TX 83 53 59 39 61 / 10 90 70 10 0
TERRELL, TX 83 59 61 35 60 / 10 90 70 10 5
CORSICANA, TX 84 63 65 35 64 / 10 70 80 10 5
TEMPLE, TX 84 63 64 39 64 / 10 80 80 10 5
MINERAL WELLS, TX 84 42 51 33 63 / 10 90 40 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82