Tornadoes and Damaging Wind in North Carolina, April 6, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
957 AM EDT MON APR 6 2009

.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS THE EASTERN CAROLINAS EARLY
THIS AFTERNOON...BRINGING WITH IT A BREEZY/WINDY DAY WITH THE
LIKELIHOOD OF SHOWERS AND THUNDERSTORMS UP UNTIL IT MOVES OFF THE
COAST. ARCTIC HIGH PRESSURE WILL BUILD IN BEHIND THIS FRONT THROUGH
WEDNESDAY...RESULTING IN UNSEASONABLY COOL TEMPERATURES THROUGH
WEDNESDAY. TEMPERATURES MORE TYPICAL OF APRIL WILL RETURN THURSDAY
THROUGH SUNDAY...WITH RAIN CHANCES INCREASING FRIDAY AND FRIDAY
NIGHT AHEAD OF THE NEXT COLD FRONT.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...FRONT IS MOVING INTO THE FORECAST AREA
WITH A BAND OF CONVECTION ALONG THE FRONT AND ANOTHER AREA OF
CONVECTION OUT AHEAD OF THE FRONT. MOST OF THE ACTIVITY IS IN THE
FORM OF SHOWERS WITH ONLY A FEW AREAS OF LIGHTNING. STORM MOTION
ON THE ORDER OF 40 KT...VAD WIND SHOWING 45 TO 50 KT AT 2K FT...SO
EVEN LIGHT SHOWERS COULD END UP WITH WIND GUSTS EXCEEDING 40 MPH.

ONCE FRONT PASSES SKIES WILL CLEAR AND DRIER AIR WILL BEGIN
FILTERING IN. ACROSS WESTERN AREAS TEMPS WILL REBOUND UNDER APRIL
SUN BUT CLOSER TO THE COAST RECOVERY WILL BE A LITTLE TOUGHER.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM MONDAY...UNSEASONABLY COOL WEATHER WILL DOMINATE THE
PERIOD...WITH THE MAIN FORECAST CHALLENGE BEING THE POTENTIAL FOR
FREEZING TEMPERATURES AROUND DAYBREAK ON WEDNESDAY.

THERE WILL BE A TIGHT GRADIENT BETWEEN HIGH PRESSURE SETTLING OVER
THE GULF OF MEXICO...AND LOW PRESSURE LIFTING INTO EASTERN
CANADA...WHILE A SERIES OF IMPULSES ROUNDS THE BASE OF THE UPPER
TROF. AS A RESULT...THE BOUNDARY LAYER WILL NOT FULLY DECOUPLE
TUESDAY NIGHT AND TEMPS WILL BE PREVENTED FROM BOTTOMING OUT.
WITH WINDS STAYING UP AROUND 5-7 KT FROST IS NOT A CONCERN...BUT
TEMPS COULD BRIEFLY DIP BELOW FREEZING AROUND SUNRISE. IF THE LAST
UPPER IMPULSE CROSSING THE AREA AROUND 06Z WED IS SLOWER OR
STRONGER THAN EXPECTED...TEMPS WILL STAY ABOVE FREEZING. A FASTER
OR WEAKER IMPULSE WOULD ALLOW FOR A LONGER DURATION OF FREEZING
TEMPS...AND PERHAPS COOLER THAN THE CURRENTLY ADVERTISED 28-32
DEGREES. STILL ENOUGH UNCERTAINTY TO HOLD OFF ON ANY 4TH PERIOD
FREEZE WATCH...SO WILL LEAVE IT TO THE DAY CREW TO GO FOR EITHER A
WATCH OR A WARNING.

DAYTIME TEMPS WILL ALSO RUN 15-20 DEGREES BELOW NORMAL THROUGH THE
PERIOD.  EVEN WITH MIXING TO 800MB ON TUESDAY...MID 50S IS ABOUT THE
BEST WE CAN DO.  LOW-LEVEL THERMAL TROF STARTS TO LIFT OUT ON
WEDNESDAY...BUT TEMPS WILL STRUGGLE TO CRACK 60 IN THE AFTERNOON.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 AM MONDAY...RETURN FLOW BEGINS TO SET UP OUT OF THE WEST
ON WEDNESDAY NIGHT AS THE SFC RIDGE WILL REMAIN SUPPRESSED TO OUR
SOUTH. THIS WILL MEAN AN END TO THE FREEZE THREAT OF THE NIGHT
BEFORE...AS TEMPS SHOULD BOTTOM OUT IN THE LOWER 40S.

SFC HIGH WILL TAKE UP RESIDENCE OFF THE FLORIDA COAST BY THURSDAY
MORNING AND SOLID RETURN FLOW WILL ALLOW SEASONAL TEMPS TO RETURN.
CHANCE OF SHOWERS AND STORMS FRIDAY AND FRIDAY NIGHT AHEAD OF A
COLD FRONT ASSOCIATED WITH A PROGRESSIVE UPPER TROF. LOW AMPLITUDE
OF THE UPPER FEATURE WILL LIMIT ANY POST-FRONTAL CAA...SO EXPECT
MILD AND DRY CONDITIONS FOR THE WEEKEND.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
A COLD FRONT WILL MOVE THROUGH THE FLO/LBT TERMINALS 14Z-15Z AND THE
COASTAL TERMINALS 17Z-18Z. GENERALLY MVFR CEILINGS BLO 2K EXPECTED
PRIOR TO FROPA ALONG WITH TEMPO SHOWERS REDUCING VISIBILITIES TO
3SM-5SM. ALSO...SEA FOG WILL AFFECT MYR/CRE BUT EXPECT VISIBILITIES
TO REMAIN MVFR OR BETTER DUE TO STRONG SOUTHWEST COMPONENT SURFACE
WINDS. ANY IFR THIS MORNING PRIOR TO FROPA SHOULD BE VERY SHORT
LIVED. WINDS WILL BE SOUTH SOUTHWEST AT 10-15 KNOTS WITH GUSTS TO
20-25 KNOTS.

ALONG THE COLD FRONT EXPECT THE BEST CHANCE OF THUNDERSTORMS. ATTM
RADAR INDICATES WEST OF FLO/LBT A COUPLE OF NARROW BANDS OF SHOWERS
ALONG THE FRONT WITH MODERATE TO HEAVY RAIN INDICATED. THERE IS SOME
ISOLATED THUNDERSTORMS OCCURRING IN THESE BANDS...THUS WILL CONTINUE
TO INDICATE TEMPO THUNDERSTORMS AT THE TERMINALS AT TIME OF FROPA.
VISIBILITIES WILL LIKELY DROP TO MVFR WITH THE PRECIPITATION. SINCE
THE ACTIVITY IS MOVING VERY RAPIDLY AND NOT WIDESPREAD DO NOT THINK
IFR VISIBILITIES WILL LAST MORE THAN 20 MINUTES AT ANY ONE TIME.

PRECIPITATION SHOULD DISSIPATE RAPIDLY AFTER FROPA WITH CEILINGS
IMPROVING TO AROUND 4K. WINDS WILL SHIFT TO THE WEST SOUTHWEST AND
INCREASE TO 20 KNOTS WITH GUSTS TO 30-35 KNOTS. THERE WILL BE
PERIODS OF SCATTERED SKIES THIS AFTERNOON. WINDS GRADUALLY
DECREASE THROUGH THE EVENING BY MIDNIGHT SHOULD DECREASE TO AROUND
10 KNOTS. SOME SC/AC CEILINGS 6-9K POSSIBLE OVERNIGHT.

EXTENDED OUTLOOK THROUGH FRIDAY...VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM MONDAY...STRONG SOUTHWESTERLY FLOW WILL CONTINUE
UNTIL COLD FRONT MOVES ACROSS THE WATERS...EARLY THIS AFTERNOON.
SCA CONTINUES FOR ALL ZONES AND WILL CONTINUE INTO THE LATER PART
OF TUE. BEHIND THE FRONT SURFACE FLOW SHIFTS TO OFFSHORE BUT
COMBINATION OF TIGHT GRADIENT AND DEVELOPING STRONG COLD ADVECTION
PUSH WINDS TO THE DOORSTEP OF GALE CRITERIA. WILL LIKELY SEE SOME
GUSTS EXCEEDING GALE FORCE...BUT AT THIS TIME DOESNT LOOK LIKE
ENOUGH TO WARRANT UPGRADE TO GALE WARNING.

SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM MONDAY...TIGHT AND MAINLY WESTERLY GRADIENT WILL DOMINATE
FOR MOST OF THE PERIOD.  INITIAL STRONG CAA AND PERSISTENT COOL AIR
MASS WILL ALLOW FOR DEEP MIXING TO CONTINUE EVEN THROUGH MUCH OF
TUESDAY NIGHT.  WIND SPEEDS FINALLY DROP CLEANLY BELOW SCA AROUND
06Z WED WITH A SLIGHT VEERING TO THE NW AS THE LAST VORT ROUNDS THE
BASE OF THE UPPER TROF.  SEAS WILL REMAIN FAIRLY AGITATED THROUGH
TUESDAY NIGHT...ESPECIALLY NEAR FRYING PAN SHOALS WHERE THE FETCH IS
MUCH LONGER IN THIS WESTERLY TRAJECTORY.  USE OF THE STRONGER NAM
WIND FIELDS DICTATES BUMPING UP THE WNA WAVE GUIDANCE.  WATERS THAT
ARE MORE BLOCKED WILL ONLY SEE MARGINAL SCA SEAS DURING THE DAY ON
TUESDAY...WHILE 7-8 FT WILL BE THE RULE ALONG THE SHOALS AND SCA
WILL CONTINUE WELL INTO THE NIGHT.  NEAR SHORE SEAS JUST 2-3 FT DUE
TO OFFSHORE TRAJECTORY.

SFC AND UPPER RIDGING WILL BE THE MAIN PLAYERS ON WEDNESDAY.
GRADIENT RELAXES ENOUGH THAT WINDS WILL DROP OFF TO AROUND 15 KT.
SHOULD REMAIN THERE AS THEY BACK AROUND TO SW IN THE
AFTERNOON...WITH ANY NEW TIGHTENING OF THE GRADIENT PROBABLY OFFSET
BY INCIPIENT WARM ADVECTION.  SEAS SHOULD REMAIN 2-4 FT WITHIN 20NM.

LONG TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
SFC HIGH OVER THE GULF OF MEXICO WILL MIGRATE ACROSS
FLORIDA...WITH SW RETURN FLOW SETTING UP ALONG THE CAROLINA COAST.
GRADIENT WILL BE FAIRLY MODEST...AND LOW-LEVEL WAA WILL PREVENT A
LOT OF MIXING. THEREFORE HAVE LIMITED WIND SPEEDS TO 15 TO
OCCASIONALLY 20 KT. HOWEVER THE SW AND AT TIMES EVEN SOUTHERLY
WIND DIRECTION WILL PROVIDE A LONG FETCH...WITH SEAS BUILDING
CLOSE TO SCA THRESHOLDS BY THE END OF THE PERIOD. IF ANYTHING THIS
FORECAST HEDGES TO THE LOW SIDE OF WNA WAVE GUIDANCE...WHICH IS
DOMINATED BY WIND WAVE FROM THE TOO-STRONG GFS.

&&

.CLIMATE...
THE UPCOMING COLD BLAST APPEARS TO BE A POTENTIALLY DAMAGING EVENT
FROM AN AGRICULTURAL PERSPECTIVE. COINCIDENTALLY IT WILL PRECISELY
MATCH THE DATE OF THE WORST NIGHT OF THE APRIL 2007 FREEZE EVENT
THAT CAUSED AT LEAST 98 MILLION DOLLARS DAMAGE TO NCS FRUIT AND NUT
CROPS (SOURCE: SOUTHEAST FARM PRESS, MAY 11 2007) AND LEFT 56 NC
COUNTIES IN FEDERAL DISASTER AREA STATUS. (SOURCE: ASHEVILLE
CITIZEN-TIMES, APR 9 2009)

THE 2007 FREEZE SET NOT ONLY DAILY LOW TEMPERATURE RECORDS BUT ALSO
ESTABLISHED ALL-TIME LOW TEMPERATURES AT MANY LOCATIONS IN OUR
FORECAST AREA FOR THE ENTIRE MONTH OF APRIL. HERE IS A SUMMARY OF
THE HOW THE UPCOMING POSSIBLE FREEZE COMPARES WITH THE 2007 EVENT.

LOCATION      RECORD LOW   ALL-TIME LOW  LOW TEMP ON    FORECAST LOW
              FOR APR 8     FOR APRIL    APR 8 2007    FOR APR 8 2009

WILMINGTON      29/2007       28/1875*       29             31
FLORENCE SC     26/2007       26/2007        26             29
N MYRTLE BEACH  29/2007       29/2007        29             32
LUMBERTON NC    22/2007       22/2007#       22             29

* APRIL 19 1875, APRILS ALL-TIME RECORD LOW FOR WILMINGTON NC #
  INCLUDES DATA FROM THE LUMBERTON CO-OP SITE GOING BACK TO 1903

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ250-252-254-
     256.

&&

NEAR TERM...III
SHORT TERM...RAS
LONG TERM...RAS
AVIATION...EH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE WILMINGTON NC
720 AM EDT MON APR 6 2009

NCZ097-100-101-071130-
PENDER-BRUNSWICK-NEW HANOVER-
720 AM EDT MON APR 6 2009

...TORNADO WATCH 121 IN EFFECT UNTIL 1 PM EDT THIS AFTERNOON...
...MODERATE RISK OF RIP CURRENTS IN EFFECT THROUGH THIS EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   TORNADO WATCH.
   MODERATE RISK OF RIP CURRENTS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

...WEDNESDAY MORNING FREEZE POTENTIAL...
WEDNESDAY MORNING LOW TEMPERATURES ARE FORECAST TO DROP TO AROUND
30 DEGREES...EXCEPT ALONG THE IMMEDIATE COAST WHERE LOW 30S WILL BE
COMMON. THE POSSIBILITY EXISTS THAT LOCATIONS COULD EXPERIENCE UP
TO 6 HOURS AT OR BELOW 32 DEGREES. THIS POTENTIAL FREEZE COULD
HAVE A DEVASTATING EFFECT ON THE AGRICULTURAL COMMUNITY IF STEPS
ARE NOT TAKEN TO PROTECT AND SAFEGUARD PLANTS...CROPS AND ETC. A
FREEZE WATCH MAY BE ISSUED TODAY TO HIGHLIGHT THIS POSSIBILITY. IF
THE FREEZE POTENTIAL IS A CERTAINTY ACROSS THE AREA...THEN THE
WATCH COULD BE BYPASSED ALLOWING THE FREEZE WARNING TO BE ISSUED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FROM MID MORNING THROUGH EARLY
AFTERNOON.

NCZ087-096-099-SCZ017-023-024-032>034-039-046-071130-
ROBESON-BLADEN-COLUMBUS-MARLBORO-DARLINGTON-DILLON-FLORENCE-MARION-
HORRY-WILLIAMSBURG-GEORGETOWN-
720 AM EDT MON APR 6 2009

...TORNADO WATCH 121 IN EFFECT UNTIL 1 PM EDT THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST NORTH CAROLINA AND
NORTHEAST SOUTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   TORNADO WATCH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

...WEDNESDAY MORNING FREEZE POTENTIAL...
WEDNESDAY MORNING LOW TEMPERATURES ARE FORECAST TO DROP TO AROUND
30 DEGREES...EXCEPT ALONG THE IMMEDIATE COAST WHERE LOW 30S WILL BE
COMMON. THE POSSIBILITY EXISTS THAT LOCATIONS COULD EXPERIENCE UP
TO 6 HOURS AT OR BELOW 32 DEGREES. THIS POTENTIAL FREEZE COULD
HAVE A DEVASTATING EFFECT ON THE AGRICULTURAL COMMUNITY IF STEPS
ARE NOT TAKEN TO PROTECT AND SAFEGUARD PLANTS...CROPS AND ETC. A
FREEZE WATCH MAY BE ISSUED TODAY TO HIGHLIGHT THIS POSSIBILITY. IF
THE FREEZE POTENTIAL IS A CERTAINTY ACROSS THE AREA...THEN THE
WATCH COULD BE BYPASSED ALLOWING THE FREEZE WARNING TO BE ISSUED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FROM MID MORNING THROUGH EARLY
AFTERNOON.

AMZ250-252-254-256-071130-
SURF CITY TO CAPE FEAR NC OUT 20 NM-
CAPE FEAR NC TO LITTLE RIVER INLET SC OUT 20 NM-
LITTLE RIVER INLET TO MURRELLS INLET SC OUT 20 NM-
MURRELLS INLET TO SOUTH SANTEE RIVER SC OUT 20 NM-
720 AM EDT MON APR 6 2009

...SMALL CRAFT ADVISORY IN EFFECT UNTIL 8 PM EDT TUESDAY...
...TORNADO WATCH 121 IN EFFECT UNTIL 1 PM EDT THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SMALL CRAFT ADVISORY.
   TORNADO WATCH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SMALL CRAFT ADVISORY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

HOEHLER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON NC
939 AM EDT MON APR 6 2009

NCZ087-096-099-SCZ024-033-034-061430-
COLUMBUS-BLADEN-ROBESON-DILLON-MARION-HORRY-
939 AM EDT MON APR 6 2009

...STRONG THUNDERSTORMS MOVING ACROSS PARTS OF THE AREA...

AT 9:40 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN
AREA OF STRONG THUNDERSTORMS IN NORTHERN MARION COUNTY SOUTH
CAROLINA. THIS AREA OF THUNDERSTORMS IS MOVING OFF TO THE NORTHEAST
RAPIDLY AT 40 MPH. THESE STORMS HAVE THE CAPABILITY OF PRODUCING
SMALL HAIL...WIND GUSTS IN EXCESS OF 40 MPH AND BRIEF HEAVY
DOWNPOURS.

COMMUNITIES IN THE PATH OF THESE STORMS ARE ELIZABETHTOWN...
MULLINS...WHITEVILLE...ABBOTTSBURG...ALLSBROOK...BARNESVILLE...
BAYBORO...BLADENBORO...BOARDMAN...CARVERS...CHADBOURN AND CHERRY
GROVE.

&&
STAY TUNED TO NOAA WEATHER RADIO ALL HAZARDS FOR FURTHER DETAILS OR
UPDATES. FOR ADDITIONAL WEATHER INFORMATION...CHECK OUR WEB SITE AT
WEATHER.GOV/ILM.

15