Historic Winter Storm 1/28/10-1/30/10

[Athensman]

Nashville,TN

Quote:TAKING A LOOK AT THE FORECAST THROUGH EARLY NEXT WEEK...INTERESTING
WEATHER SCENARIO COULD DEVELOP THURSDAY NIGHT INTO FRIDAY WITH
PLENTIFUL MOISTURE IN PLACE...AND TEMPS THRU NIGHT AND FRIDAY NOT
EXPECTED TO GET OUT OF THE 20S. SFC LOW IS EXPECTED TO TRACK S OF
THE MID STATE...AND THIS COULD DEVELOP INTO A WINTRY PRECIP
RETURN TO THE MID STATE. LOW TRACK WILL BE THE KEY HERE...AND AT
THIS TIME...WILL GO WITH CURRENT FORECAST REASONING. HOWEVER...
THIS SITUATION WILL NEE ED TO BE CAREFULLY MONITORED THRU THE
NEXT SEVERAL DAYS FOR FURTHER FORECAST CLARIFICATION. UNSEASONABLE
COLD TEMPS WILL CONTINUE ACROSS THE MID STATE OVER THE WEEKEND
INTO EARLY NEXT WEEK AS RIDGING INFLUENCES SURFACE AND ALOFT
BUILD ACROSS THE MID STATE.

[Athensman]

Bham NWS

Quote:THE NEXT SYSTEM BEGINS TO TAKE SHAPE THURSDAY AND FRIDAY. THE
MEDIUM RANGE MODELS HAVE BEEN IN DISAGREEMENT WITH A FEW OF THE KEY
ELEMENTS. THE MODELS DO HAVE SOME SIMILARITIES IN THE SURFACE LOW
TRACK...BUT TIMING AND THERMODYNAMIC PROFILES ARE CAUSING MUCH
UNCERTAINTY IN THIS TIME FRAME. THE GFS IS STILL ONE OF THE FASTEST
MODELS WITH THE NOGAPS/CMC/NAEFS/ECMWF UP TO 10 HOURS SLOWER. THE
GFS IS ALSO ON THE COLDER SIDE OF THE SOLUTIONS. THEREFORE...IT
LOOKS LIKE CENTRAL ALABAMA WILL HAVE A PRETTY GOOD SHOT AT RAIN AND
A FEW THUNDERSTORMS...CENTERED ON THE THURSDAY NIGHT/FRIDAY MORNING
TIME FRAME. TOOK SOMEWHAT OF A MIX OF MODEL SOLUTIONS...BUT
SLIGHTLY SLOWER THAN THE GFS AND SLIGHTLY WARMER.

AT THIS TIME...KEPT THE MENTION OF RAIN OR SNOW EARLY FRIDAY INTO
FRIDAY NIGHT. IF THE GFS WERE TO VERIFY...FREEZING RAIN AND SLEET
WOULD BE POSSIBLE THURSDAY NIGHT INTO FRIDAY. EVEN THOUGH THE GFS
SEEMS TO BE MOST AGGRESSIVE WITH THE ARRIVAL OF THE COLD AIR...WE
ARE DEALING WITH A MODIFIED ARCTIC AIRMASS WHICH NOTORIOUSLY IS NOT
HANDLED BY THE MODELS DUE TO ITS SHALLOW NATURE. WE WILL CONTINUE
TO WATCH THIS TIME FRAME VERY CAREFULLY FOR THE POTENTIAL OF SOME
WINTRY WEATHER. ON THE SOUTH SIDE OF THE SYSTEM...INSTABILITY SEEMS
TO BE LACKING AND ANY STRONGER STORMS SHOULD REMAIN CONFINED TO
COASTAL ZONES. PRECIPITABLE WATER VALUES CLIMB INTO THE 1 TO 1.5
INCH RANGE DUE TO A ROBUST LOW LEVEL JET THURSDAY NIGHT. A
FEW LOCATIONS MAY RECEIVE LOCALLY HEAVY RAIN.

COLDER CONDITIONS WILL CERTAINLY FOLLOW THE PASSAGE OF THE FRONT BY
NEXT WEEKEND.

[Athensman]

HPC

Quote:From this morning's HPC discussion:
IN THIS PATTERN...THERE IS A MAJOR THREAT FOR HEAVY GULF COAST
STATES PCPN WITH A PRONOUNCED SWATH OF SIGNIFICANT HEAVY SNOW/ICE
FURTHER INLAND AS SRN STREAM SYSTEM ENERGY PROGRESSES UNDERNEATH
SOUTHWARD SUNK NRN STREAM COLD AIR. THE MAIN WINTER THREAT SEEMS
TO FOCUS OVERTOP LOW PASSAGE SPREADING THU-SAT FROM THE SRN PLAINS
TO THE MID-LOWER MS AND TN/OH VALLEYS THEN SOUTH-CENTRAL
APPALACHIANS/MID-ATLANTIC STATES. RECENT TRENDS INCLUDING MOST 00Z
GUIDANCE AND INCREASED FLOW SEPARATION BETWEEN THE POLAR VORTEX
AND THE SYSTEM MOVING THROUGH THE SOUTH AND EAST THEN SEEMS TO AT
LEAST TEMPORARILY LESSEN A SUBSEQUENT HEAVY SNOW THREAT FOR NEW
ENGLAND WITH COASTAL LOW DEEPENING SLIGHTLY FURTHER OFFSHORE...BUT
THE 06 UTC GFS HAS BUCKED THAT TREND TO SOME DEGR

[Athensman]

Who said this ?
FFC

Quote:.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE NEXT SOUTHERN STREAM SYSTEM PLOWS INTO SOUTHERN CALIFORNIA ON
TUESDAY. GLOBAL MODELS DIVERGE SOMEWHAT FROM THAT POINT ON WITH
THE FASTER GFS SHOWING THE SURFACE LOW REACHING GEORGIA THURSDAY
NIGHT AND THE SLOWER ECMWF DELAYING IT UNTIL FRIDAY NIGHT. THIS
FORECAST IS A COMPROMISE BETWEEN THOSE TWO SOLUTIONS. PRECIP
SHOULD BREAK OUT BY LATE THURSDAY AS ISENTROPIC ASCENT INCREASES
ACROSS A FRONTAL BOUNDARY STRETCHING ALONG THE I-85 CORRIDOR FROM
THE CAROLINAS TO ALABAMA. P-TYPE A BIT OF A CONCERN ACROSS FAR
NORTH GA WITH ONSET OF PRECIP TOWARD NIGHT FALL AND STRONG
SURFACE HIGH TO THE NORTHWEST PUSHING DRY SURFACE AIR IN FROM THE
N/NE. LOOKS LIKE THE ATL/AHN AREAS WILL SEE ALL RAIN UNTIL A
POSSIBLE MIX OR BRIEF CHANGEOVER TO -SN ON THE BACKSIDE PRIOR TO
PRECIP ENDING FRIDAY NIGHT. THE STRONG AND COOL HIGH TO OUR
NORTHWEST BUILDS INTO THE SOUTHEASTERN STATES NEXT WEEKEND.

[ROLLTIDE]

Nashville, HWO update

Quote:000
FLUS44 KOHX 251758
HWOOHX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
1158 AM CST MON JAN 25 2010

TNZ005>011-022>034-056>066-075-077>080-093>095-261800-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DEKALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
1158 AM CST MON JAN 25 2010

...WINTER STORM OUTLOOK FOR SIGNIFICANT SNOW AND ICE...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A WINTER STORM IS FORECAST FOR MIDDLE TENNESSEE LATE THIS
WEEK...PRODUCING SIGNIFICANT SNOW AND ICE ACCUMULATIONS. COMPUTER
MODELS HAVE BECOME CONSISTENT WITH THIS FORECAST OVER THE LAST
SEVERAL DAYS...AND INDICATE THE POTENTIAL FOR A SIGNIFICANT
WINTER STORM BY THE END OF THE WEEK. THOSE PLANNING TRAVEL DURING
THAT PERIOD SHOULD REMAIN ABREAST OF THE LATEST WEATHER FORECAST.

A LOW PRESSURE AREA WILL MOVE ALONG THE GULF COASTAL REGION AND
PULL IN COLDER AIR FROM THE NORTH.

THE TIME OF GREATEST IMPACT WILL BE THURSDAY NIGHT THROUGH FRIDAY
NIGHT...AND THIS IS HOW THINGS ARE EXPECTED TO UNFOLD...

...FOR THURSDAY NIGHT...WE LOOK FOR A CHANGE FROM RAIN TO SNOW
ACROSS NORTHERN AREAS...WITH A MIX OF RAIN...SLEET...AND FREEZING
RAIN ACROSS THE SOUTH. SNOW AND ICE ACCUMULATIONS ARE POSSIBLE.

...FOR FRIDAY...SNOW CONTINUES ACROSS THE NORTH...WITH SNOW ALSO
SPREADING INTO SOME SOUTHERN AREAS DURING THE DAY. MEANWHILE PARTS
OF SOUTHERN MIDDLE TENNESSEE WILL CONTINUE TO EXPERIENCE A MIX OF
RAIN...SLEET...AND FREEZING RAIN. SIGNIFICANT ACCUMULATIONS OF
SNOW AND ICE ARE LIKELY.

...FOR FRIDAY NIGHT...MUCH COLDER AIR SPREADS IN...WITH SNOW
EXPECTED OVER ALL OF THE MID STATE. MORE SNOW AND ICE
ACCUMULATIONS ARE LIKELY.

THERE IS STILL SOME UNCERTAINTY REGARDING THE EVENTUAL TRACK OF
THE LOW PRESSURE AREA ALONG THE GULF COAST. THEREFORE...IT IS
DIFFICULT TO PROVIDE A RELIABLE FORECAST OF TOTAL SNOW AND ICE
ACCUMULATIONS AT THIS TIME. HOWEVER...IT APPEARS THAT SIGNIFICANT
SNOW AND ICE ACCUMULATION WILL OCCUR OVER A LARGE PART...IF NOT
ALL...OF THE MID STATE BY THE TIME PRECIPITATION TAPERS OFF LATE
FRIDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

IF THIS WINTER STORM DEVELOPS AS EXPECTED...SPOTTERS AND LOCAL
EMERGENCY MANAGEMENT OFFICIALS ARE ENCOURAGED TO REPORT SNOW AND ICE
ACCUMULATIONS TO THE NATIONAL WEATHER SERVICE IN NASHVILLE

[Joe-Nathan]

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1155 AM CST MON JAN 25 2010

Quote:THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARKANSAS...SOUTHWEST ARKANSAS...NORTH CENTRAL LOUISIANA...
NORTHWEST LOUISIANA...SOUTHEAST OKLAHOMA...EAST TEXAS AND
NORTHEAST TEXAS.

DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

SCATTERED SHOWERS WILL RETURN TO PORTIONS OF SOUTHWEST ARKANSAS...SOUTHEAST
OKLAHOMA...AND EAST TEXAS WEDNESDAY NIGHT...AHEAD OF AN UPPER LEVEL
DISTURBANCE THAT WILL PROGRESS EAST ACROSS NEW MEXICO INTO FAR WEST
TEXAS. THESE SHOWERS WILL BECOME MORE WIDESPREAD THURSDAY AS THIS
STORM SYSTEM BEGINS TO TRAVERSE EAST ACROSS TEXAS...WITH THUNDERSTORMS
DEVELOPING ACROSS EAST TEXAS AND NORTH LOUISIANA THURSDAY AFTERNOON
AND NIGHT AS WARM...MOIST...AND UNSTABLE AIR AT THE SURFACE RETURNS
NORTH TOWARDS THE INTERSTATE 20 CORRIDOR OF EAST TEXAS AND NORTH
LOUISIANA. THE DEGREE OF INSTABILITY REMAINS IN QUESTION AT THIS
TIME...BUT STRONG SHEAR WILL RESULT IN THUNDERSTORMS ORGANIZING ACROSS
THE WARM SECTOR BY THURSDAY EVENING...WITH AT LEAST AN ISOLATED SEVERE
WEATHER THREAT POSSIBLE THROUGH THURSDAY NIGHT...BEFORE DIMINISHING
FROM WEST TO EAST LATE WITH THE PASSAGE OF A COLD FRONT. LOCALLY HEAVY
RAIN WILL BE POSSIBLE FROM SHOWERS AND THUNDERSTORMS AS WELL...WITH
WIDESPREAD RAINFALL AMOUNTS OF ONE TO TWO INCHES POSSIBLE. [COLOR="Blue"]THE RAIN
MAY BRIEFLY CHANGE OVER TO A WINTRY MIX LATE THURSDAY NIGHT AND FRIDAY
ACROSS SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...NORTHEAST TEXAS...AND
NORTHWEST LOUISIANA...BUT ANYTHING THAT DEVELOPS SHOULD BE LIGHT. [/COLOR]

SPOTTER INFORMATION STATEMENT

SPOTTER ACTIVATION WILL NOT BE NEEDED.

[ROLLTIDE]

Canadian:



GFS:

[ROLLTIDE]

[ROLLTIDE]

HPC

Quote:EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
133 PM EST MON JAN 25 2010

VALID 12Z THU JAN 28 2010 - 12Z MON FEB 01 2010

...MAJOR WINTER STORM POTENTIAL ACROSS THE MID-SRN US TIER
STATES...
TELECONNECTIONS WITH A NEGATIVE HEIGHT ANOMALY NEAR 50N 150W FAVOR
RIDGING ALOFT DOWNSTREAM FROM WRN CANADA INTO THE WRN US...DEEP
COLD TROUGHING DUG DOWN FROM CANADA INTO THE EAST-CENTRAL US...AND
AN ACTIVE SOUTHERN BRANCH OF THE JET CUTTING UNDERNEATH THROUGH
THE US SRN TIER STATES. THIS FLOW AND EVEN WITH GUIDANCE BRINGING
ERN PACIFIC TROUGH ENERGY ALOFT INCREASINGLY INLAND ACROSS THE
WEST-CENTRAL US BY NEXT WEEKEND...THE MODELS AND ENSEMBLES AGREE
ON THESE IDEAS AND FOR THE MOST PART FORECAST CONFIDENCE IS ABOVE
NORMAL DAYS 3-7 DESPITE SMALLER SCALE DETAIL VARIANCE.

HOWEVER...THE 00Z GFS/UKMET AND TO A LESSER EXTENT 00Z GFS
ENSEMBLES GENERALLY OUTPACE THE REMAINDER OF DETERMINISTIC AND
ENSEMBLE MEAN GUIDANCE. WITH SOLUTIONS OVERALL ON THE FAST EDGE
OF THE FULL ARRAY OF MODEL AND ENSEMBLE SOLUTIONS...THE 00Z
GFS/UKMET WERE CONSIDERED PLAUSIBLE BUT LESS LIKELY OPTIONS. OF
THE REMAINING GUIDANCE...THE 00Z ECMWF/CANADIAN HAVE KEPT BETTER
DAY-TO-DAY CONTINUITY OVER THE PAST FEW DAYS WITH SYSTEM TIMING
AND GENERAL TRACK...CLUSTERING CLOSELY WITH THE BULK OF ENSEMBLE
MEMBER GUIDANCE. DUE TO THEIR GOOD CONTINUITY AND FAVORABLE
ENSEMBLE SUPPORT/LOW SPREAD...FINAL HPC MEDIUM RANGE GUIDANCE
MAINTAINS CLOSE CONTINUITY AND REMAINS PRIMARILY DERIVED FROM A
BLEND OF THE 00Z ECMWF/CANADIAN...A SOLUTION CLUSTER NOW GENERALLY
JOINED BY THE 06Z GFS AND MUCH 12Z GUIDANCE.

IN THIS PATTERN...THERE IS A MAJOR THREAT FOR HEAVY GULF COAST
STATES PCPN WITH A PRONOUNCED SWATH OF SIGNIFICANT HEAVY SNOW/ICE
FURTHER INLAND AS SRN STREAM SYSTEM ENERGY PROGRESSES UNDERNEATH
SOUTHWARD SUNK NRN STREAM COLD AIR. THE MAIN WINTER THREAT SEEMS
TO FOCUS OVERTOP LOW PASSAGE SPREADING THU-SAT FROM THE SRN PLAINS
TO THE MID-LOWER MS AND TN/OH VALLEYS THEN SOUTH-CENTRAL
APPALACHIANS/MID-ATLANTIC STATES. 00Z GUIDANCE TRENDS AND
INCREASED FLOW SEPARATION BETWEEN THE POLAR VORTEX AND THE SYSTEM
MOVING THROUGH THE SRN AND ERN US DECREASED SUBSEQUENT HEAVY SNOW
THREAT FOR NEW ENGLAND WITH COASTAL LOW DEEPENING SLIGHTLY FURTHER
OFFSHORE. HOWEVER...06/12Z GUIDANCE HAS TO SOME DEGREE REVERSED
THAT TREND AS PER MORE WINTERY PCPN INLAND ON THE NW PERIPHERY OF
THE WRAP-BACK PCPN SHIELD ACROSS THE MID-ATLANTIC AND SE NEW
ENG...ALBEIT WITH THE 12Z UKMET/ECMWF SLIGHTLY LESS PROGRESSIVE.
THIS HIGHLIGHTS LINGERING MODEL RUN TO RUN SENSITIVITY WITH LESS
PREDICTABLE SMALLER SCALE COMPONENTS AND INTERACTIONS THAT MAY NOT
BE RESOLVED UNTIL SHORT RANGE TIME SCALES.

[ROLLTIDE]