Post by SKYSUMMIT on Jul 17, 2014 14:30:27 GMT -6
LIX AFD:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
329 PM CDT THU JUL 17 2014
.SYNOPSIS...
LATEST SURFACE ANALYSIS SHOWED THE FRONTAL BOUNDARY STRADDLING THE
CENTRAL GULF COAST TO WEST TEXAS. IN ADDITION...A LARGE SURFACE
HIGH WAS LOCATED OVER THE OHIO VALLEY AND A LIGHT AND VARIABLE
FLOW WAS NOTED OVER MID SOUTH...MISSISSIPPI AND LOUISIANA. SURFACE
DEWPOINTS WERE IN THE LOWER 60S. PRECIPITABLE WATER VALUES ON A
PLANER VIEW AT 12Z SHOWED A SWATH OF MOISTURE FROM NORTHWEST GULF TO
SOUTHERN OKLAHOMA WITH 1.9 INCHES AND 1.2 INCHES OVER SOUTHEAST
LOUISIANA...STABLE DRY AIR RETREATING EAST. UPPER AIR ANALYSIS
SHOWED THE POSITIVELY TILTED SHORT WAVE OVER KANSAS. ISOTACH
ANALYSIS SHOWED SOUTHWEST JET MAX OF 65 KNOTS AHEAD OF THE SHORT
WAVE. 18
&&
.DISCUSSION...
THE OLD BOUNDARY WILL BEGIN TO MOVE BACK NORTH THIS AFTERNOON AND
TONIGHT. THE SHORT WAVE TROUGH IS EXPECTED MOVE ACROSS THE MID
SOUTH AND MID MISSISSIPPI VALLEY LATE TONIGHT AND FRIDAY. MOISTURE
WILL QUICKLY RETURN AND DEEPEN ACROSS THE AREA TONIGHT AND
FRIDAY...WITH PRECIPITABLE WATER VALUES APPROACHING OR EXCEEDING 2
INCHES.
SOME OF THE STORMS FRIDAY AND FRIDAY NIGHT COULD BE ON THE
STRONGER SIDE WITH AN ISOLATED SEVERE STORM NOT OUT OF THE
QUESTION AS THE SHORT WAVE TROUGH INTERACTS WITH THE UNSTABLE AND
VERY MOIST AIRMASS OVER THE REGION WITH A FRONTAL BOUNDARY IN THE
VICINITY. 0-3KM HELICITY VALUES UP TO 200M/S ACROSS SOUTHWEST AND
SOUTH CENTRAL MISSISSIPPI AND EAST CENTRAL LOUISIANA FRIDAY.
HOWEVER...THE WIND FIELD WILL NOT BE PARTICULARLY STRONG WITH MID LEVEL
SOUTHWEST WINDS IN THE 25 TO 30 KNOT RANGE AND SURFACE TO 5000
FEET WITH SOUTH TO SOUTHWEST WINDS 20 KNOTS OR LESS.
WITH MOIST AIR MASS IN PLACE...LAPSE RATES ARE NOT EXPECTED TO BE
STEEP. THE SEVERE THREAT WILL LIKELY BE ISOLATED IN NATURE WITH
THE MAIN THREAT BEING DAMAGING WIND GUSTS. THE MAIN THREAT WILL BE
HEAVY RAIN WITH POSSIBLY 2 TO 4 INCHES FROM FRIDAY THROUGH SUNDAY.
RAINFALL TOTALS SINCE JULY 3RD REVEALED AMOUNTS 2 TO 5 INCHES
ACROSS THE CONCERNED AREA...NORTH HALF OF FORECAST AREA. DO EXPECT
ISOLATED NUISANCE FLOODING BUT WIDESPREAD FLOODING IS NOT EXPECTED AT
THIS TIME. CATEGORICAL RAIN CHANCE APPEAR TO BE IN ORDER FOR
FRIDAY AND FRIDAY EVENING AND LIKELY POPS FOR SATURDAY AND SUNDAY.
AFTER THE SHORT WAVE TROUGH SHIFTS TO THE EAST SATURDAY...CONVECTION
IS EXPECTED TO REMAIN ACTIVE THROUGH THE REMAINDER OF THE WEEKEND.
MOISTURE WILL REMAIN IN PLAY BUT NO REAL FOCUS. RIDGE WILL AMPLIFY OVER
THE SOUTHERN PLAINS MONDAY AND THEN RETROGRADE BACK WEST TUESDAY
AND WEDNESDAY OF NEXT WEEK...SO THIS WEAKNESS WILL ALLOW SCATTERED
CONVECTION EACH AFTERNOON MONDAY THROUGH WEDNESDAY. 18
NATIONAL WEATHER SERVICE NEW ORLEANS LA
329 PM CDT THU JUL 17 2014
.SYNOPSIS...
LATEST SURFACE ANALYSIS SHOWED THE FRONTAL BOUNDARY STRADDLING THE
CENTRAL GULF COAST TO WEST TEXAS. IN ADDITION...A LARGE SURFACE
HIGH WAS LOCATED OVER THE OHIO VALLEY AND A LIGHT AND VARIABLE
FLOW WAS NOTED OVER MID SOUTH...MISSISSIPPI AND LOUISIANA. SURFACE
DEWPOINTS WERE IN THE LOWER 60S. PRECIPITABLE WATER VALUES ON A
PLANER VIEW AT 12Z SHOWED A SWATH OF MOISTURE FROM NORTHWEST GULF TO
SOUTHERN OKLAHOMA WITH 1.9 INCHES AND 1.2 INCHES OVER SOUTHEAST
LOUISIANA...STABLE DRY AIR RETREATING EAST. UPPER AIR ANALYSIS
SHOWED THE POSITIVELY TILTED SHORT WAVE OVER KANSAS. ISOTACH
ANALYSIS SHOWED SOUTHWEST JET MAX OF 65 KNOTS AHEAD OF THE SHORT
WAVE. 18
&&
.DISCUSSION...
THE OLD BOUNDARY WILL BEGIN TO MOVE BACK NORTH THIS AFTERNOON AND
TONIGHT. THE SHORT WAVE TROUGH IS EXPECTED MOVE ACROSS THE MID
SOUTH AND MID MISSISSIPPI VALLEY LATE TONIGHT AND FRIDAY. MOISTURE
WILL QUICKLY RETURN AND DEEPEN ACROSS THE AREA TONIGHT AND
FRIDAY...WITH PRECIPITABLE WATER VALUES APPROACHING OR EXCEEDING 2
INCHES.
SOME OF THE STORMS FRIDAY AND FRIDAY NIGHT COULD BE ON THE
STRONGER SIDE WITH AN ISOLATED SEVERE STORM NOT OUT OF THE
QUESTION AS THE SHORT WAVE TROUGH INTERACTS WITH THE UNSTABLE AND
VERY MOIST AIRMASS OVER THE REGION WITH A FRONTAL BOUNDARY IN THE
VICINITY. 0-3KM HELICITY VALUES UP TO 200M/S ACROSS SOUTHWEST AND
SOUTH CENTRAL MISSISSIPPI AND EAST CENTRAL LOUISIANA FRIDAY.
HOWEVER...THE WIND FIELD WILL NOT BE PARTICULARLY STRONG WITH MID LEVEL
SOUTHWEST WINDS IN THE 25 TO 30 KNOT RANGE AND SURFACE TO 5000
FEET WITH SOUTH TO SOUTHWEST WINDS 20 KNOTS OR LESS.
WITH MOIST AIR MASS IN PLACE...LAPSE RATES ARE NOT EXPECTED TO BE
STEEP. THE SEVERE THREAT WILL LIKELY BE ISOLATED IN NATURE WITH
THE MAIN THREAT BEING DAMAGING WIND GUSTS. THE MAIN THREAT WILL BE
HEAVY RAIN WITH POSSIBLY 2 TO 4 INCHES FROM FRIDAY THROUGH SUNDAY.
RAINFALL TOTALS SINCE JULY 3RD REVEALED AMOUNTS 2 TO 5 INCHES
ACROSS THE CONCERNED AREA...NORTH HALF OF FORECAST AREA. DO EXPECT
ISOLATED NUISANCE FLOODING BUT WIDESPREAD FLOODING IS NOT EXPECTED AT
THIS TIME. CATEGORICAL RAIN CHANCE APPEAR TO BE IN ORDER FOR
FRIDAY AND FRIDAY EVENING AND LIKELY POPS FOR SATURDAY AND SUNDAY.
AFTER THE SHORT WAVE TROUGH SHIFTS TO THE EAST SATURDAY...CONVECTION
IS EXPECTED TO REMAIN ACTIVE THROUGH THE REMAINDER OF THE WEEKEND.
MOISTURE WILL REMAIN IN PLAY BUT NO REAL FOCUS. RIDGE WILL AMPLIFY OVER
THE SOUTHERN PLAINS MONDAY AND THEN RETROGRADE BACK WEST TUESDAY
AND WEDNESDAY OF NEXT WEEK...SO THIS WEAKNESS WILL ALLOW SCATTERED
CONVECTION EACH AFTERNOON MONDAY THROUGH WEDNESDAY. 18
