FXUS64 KLIX 061810
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1210 PM CST SUN DEC 6 2009
.UPDATE...
SLOW RETREATING HIGH TO THE NORTHEAST HAS HAMPERED TEMPERATURES
FROM RISING TOO QUICKLY ACROSS SOUTHERN MISSISSIPPI. THE
APPROACHING SHORT HAS SPREAD SCATTERED CLOUDS OVER THE AREA. WARM
ADVECTION WILL TAKE PLACE FROM SOUTHWEST TO NORTHEAST.
HOWEVER...WAA WILL LIKELY OCCUR LATE THIS AFTERNOON AND OVERNIGHT
ACROSS NORTHEAST ZONES. WILL LOWER HIGH TEMPS ACROSS MCB AREA.
OTHERWISE...NO SIG ISSUES.
&&
.PREV DISCUSSION... /ISSUED 423 AM CST SUN DEC 6 2009/
..ACTIVE PATTERN CONTINUES...
SHORT TERM...THE COLD TEMPS ARE ON THE WAY OUT AS OUR SFC HIGH
SHIFTS OFF TO THE NE. AFTER TEMPS QUICKLY PLUMMETED DURING THE EVN
HRS CIRRUS MOVED IN HALTING THE DROP WITH TEMPS EVENTUALLY RISING
EVERYWHERE DURING THE MORNING HRS. THAT SAID IT STILL GOT PRETTY
CHILLY AND WITH DECENT CLOUD COVER EXPECTED THIS SHOULD SET THE
STAGE FOR ONE MORE COOL DAY.
TODAY THROUGH MON...BEGINNING TODAY WE WILL START TO TRANSITION WITH
MOISTURE EXPECTED TO INCREASE ALONG WITH TEMPS. WE WILL BE UNDER
BASICALLY ZONAL FLOW AND THIS WILL SEND A FEW WEAK IMPULSES ACROSS
THE REGION WHILE A WEAK SFC WAVE WILL DEVELOP ALONG THE UPPER TX
COAST TONIGHT/EARLY MON. THIS ALONG WITH THE SFC HIGH PUSHING OFF
TO THE NE WILL CAUSE LL WINDS TO VEER BACK AROUND TO THE SSE AND
THEN SRLY. THIS WILL SLOWLY LEAD TO MOISTURE ADV AND WAA. IN FACT
ISENTROPIC LIFT/WAA SHRA MAY RETURN AS EARLY AS THIS AFTN ACROSS
THE COASTAL WATERS WEST OF THE MS RIVER AND EXTREME SWRN PARISHES
OF THE CWA. THESE SHRA WILL INCREASE IN COVERAGE THROUGH THE NIGHT
AS ISENTROPIC LIFT INCREASES. INSTABILITY WILL BE LACKING FOR THE
MOST PART SO I WILL KEEP THUNDER WORDING OUT THROUGH MON. TEMPS
TODAY WONT WARM TOO MUCH AS WAA WILL NOT BE QUITE AS STRONG TODAY
BUT BY TOMORROW HIGHS SHOULD BE BACK IN THE 60S TO NEAR 70 THANKS
TO ABOUT 24 HRS OF WAA.
MON NIGHT THROUGH WED...THINGS WILL BEGIN TO RAMP UP DURING THIS TIME
FRAME. A MUCH STRONGER DISTURBANCE WILL BE MOVING OVER THE
CONTINENTAL DIVIDE AND INTO THE PLAINS BY TUE. AT THE SAME TIME A
SFC LOW WILL DEEPEN AS IT MOVES OUT OF THE FOOTHILLS AND EAST TWRDS
THE MID MS VALLEY. THIS WILL CONTINUE TO PUMP IN THE MOISTURE OVER
THE REGION ALONG WITH WAA. THAT SAID THE BULK OF THE LIFT WILL
REMAIN WELL OFF TO OUR NORTH BUT WE SHOULD STILL HAVE BROAD LIFT
ACROSS THE AREA AS MID LVL HGHTS BEGIN TO FALL THROUGH THE DAY AND
NIGHT TUE. ON THE OTHER HAND WINDS IN THE LL WILL GREATLY INCREASE
WITH THE POSSIBILITY OF A 50KT LL JET DEVELOPING ACROSS THE REGION
TUE EVN. AS THE SFC LOW STARTS TO LIFT OUT TO THE NE TWRDS THE GRT
LAKES A TRAILING COLD FRONT WILL PUSH THROUGH THE REGION LIKELY
MAKING IT ALL THE WAY TO THE COAST BY MIDDAY WED. WITH ALL OF THAT
WE WILL SEE SCT TO NUMEROUS SHRA MON NIGHT...MAINLY DUE TO STRONG
ISENTROPIC LIFT/WAA. I WILL BEGIN TO INCLUDE THUNDER AS FORCING DOES
START TO INCREASE BUT THE THERMODYNAMIC FIELD IS STILL QUITE
UNIMPRESSIVE.
LOOKING INTO THE STRONG TO SVR POSSIBILITIES I SEE PROS AND CONS.
DURING THE DAY TUE AS LIFT SLOWLY INCREASES AND THE LL WINDS
INCREASE CONVECTION SHOULD CONTINUE IF NOT INCREASE IN COVERAGE AND
INTENSITY. THE THERMO FIELD IS STILL UNIMPRESSIVE. MID LVL LAPSE
RATES LEAVE A LOT TO BE DESIRED...AROUND 4.8C/KM(H7-H5)...VT OF
22-23C...AND SHOWALTERS RIGHT AROUND 0C TO NAME A FEW. THAT SAID THE
KINEMATIC FIELD IS IMPRESSIVE ESPECIALLY IN THE LL. I WOULD LIKE TO
SEE SLIGHTLY STRONGER MID LVL FLOW BUT H7 WINDS OF 50KTS AND H5
WINDS OF 50-60KTS ARE SUFFICIENT. THERE IS ONE THING I WILL MENTION
ABOUT THESE MID LVL WINDS...THE WINDS INCREASE TO THESE SPEEDS OVER
A LARGE AREA AND B/C OF THAT THERE IS NO REAL FOCUS UNLIKE IF WE
WERE TO SEE A LARGE AREA OF LIGHTER WINDS WITH A PUNCH OF THESE
STRONGER WINDS. OVERALL THE SYNOPTIC PATTERN IS FAVORABLE PUTTING
THE AREA UNDER THE FAVORABLE H5 HGHTS OF 576DM WHILE SFC PRESSURES
LOOK TO BE AROUND 1006-1008. ONE UNFAVORABLE THING IS WE WILL NOT BE
IN THE BEST QUADRANT OF THE UPPER JET(BASICALLY IN THE RFQ) BUT
THERE WILL BE BROAD DIVERGENCE ALOFT AND I DO MEAN BROAD. ONE MORE
THING WILL BE THE ADDED FORCING OF THE COLD FRONT WHICH SHOULD START
TO MOVE THROUGH THE AREA LATE TUE NIGHT. WITH ALL OF THAT SAID THERE
SEEMS TO BE MORE THAN ENOUGH SUPPORT TO GET STRONG AND EVEN A FEW
SEVERE STORMS. I WILL CONTINUE TO MENTION THIS RISK. AT THIS TIME I
REALLY CAN'T DEFINE AN AREA OF GREATEST RISK MAINLY DUE TO THE LACK
OF SOMETHING SIGNIFICANT TO FOCUS ON UNTIL THE FRONT STARTS TO MOVE
THROUGH. AT THAT TIME THE BEST CHANCE FOR STRONG/SVR STORMS WILL BE
ALONG THE FRONT LATE TUE NIGHT. /CAB/
LONG TERM...OVERALL THE MEDIUM RANGE MDLS ARE IN DECENT AGREEMENT.
A DEEP UPPER LOW WILL MOVE EAST ACROSS SCNTRL AND THEN SERN CANADA
WITH BASICALLY THE NRN HALF OF THE CONUS UNDER A VERY BROAD TROUGH.
THE TROUGH FLATTENS OUT ACROSS THE SRN CONUS KEEPING US UNDER ZONAL
FLOW. DUE TO THE DECENT AGREEMENT IN THE MDLS I HAVE STUCK CLOSE TO
THE 00Z MEX GUI.
WED NIGHT AND INTO THE WEEKEND...THINGS WILL BE QUIET DURING MUCH OF
THIS TIME FRAME. IN THE MID LVLS WE WILL MOSTLY REMAIN UNDER FAST
ZONAL FLOW BUT AS WE MOVE TWRDS THE END OF THE WEEK A DISTURBANCE
WILL MOVE EAST OUT OF CA ACROSS THE FOUR CORNERS AND INTO THE SRN
PLAINS. THIS LOOKS LIKE IT WILL BRING US OUR NEXT CHANCE OF
RAIN...POSSIBLY BEGINNING AS EARLY AS FRI NIGHT. HIGH PRESSURE WILL
BUILD ACROSS THE SRN CONUS BEHIND OUR COLD FRONT. THIS SHOULD BRING
IN A COOL DRY AIRMASS BACK INTO THE REGION. IF THE MID LVL TROUGH IS
DEEPER THEN THE SFC HIGH COULD PUSH A LITTLE FURTHER SOUTH WHICH
WOULD MAKE US A LITTLE COOLER THAN WHAT I CURRENTLY HAVE IN THE
FCST. AS HIGH PRESSURE WILL SLOWLY SLIDES EAST TWRDS THE ATLANTIC
STATES FRI RETURN FLOW START TO SET BACK UP ALLOWING MOISTURE TO
RETURN ONCE AGAIN. /CAB/
AVIATION...
HIGH PRESSURE SHOULD EAST PRODUCING A LIGHT EAST FLOW AT EACH TAF
SITE LATER TODAY. FLOW ALOFT IS BRINGING IN MOISTURE AND CEILINGS AT
15FKT THIS MORNING. THIS SHOULD REMAIN THE CASE THROUGH MUCH OF THE
DAY. SOME 6KFT CIELINGS WILL BEGIN TO MOVE INTO THE WESTERN 2/3RDS
OF THE AREA AROUND 00Z. SOME CONCERN TO FOG AND LOWERED CIELINGS FOR
TONIGHT AS WINDS COME AROUND TO MORE OF A SE DIR BRINGING ENOUGH
MOISTURE BACK OVER A COOL SFC. WILL SHOW SOME REDUCED VIS FOR THIS
LATE TONIGHT AS WELL AS SOME TEMPO CEILINGS AROUND OVC001.
COASTAL...
HIGH PRESSURE SHIFTS EAST TODAY...WEAK RETURN FLOW WILL DEVELOP WITH
AN INCREASE OF MOISTURE BEGINNING OVER THE REGION. A WEAK SYSTEM
WILL AFFECT THE NORTHERN GULF MONDAY WITH MAILY SHOWER ACTIVITY.
THIS SYSTEM WILL BRING BACK SOME WARMER MORE MOIST AIR OVER THE COOL
SHELF WATERS NEAR THE COAST. THIS MAY CAUSE SOME FOG TO DEVELOP LATE
TONIGHT AND MONDAY MORNING. A SHARP DISTURBANCE WILL MOVE NE OVER
THE WESTERN WATERS MON NIGHT AND TUE MORNING MOVING PERPENDICULAR TO
A WARM FRONTAL BOUNDARY. THIS WILL HELP CAUSE ADDITIONAL LIFT AS THE
AREA MOVES INTO THE COASTAL WATERS. WINDS SHOULD ACCELERATE AND
STRONG TS SHOULD ALSO BREAK OUT MONDAY NIGHT INTO TUESDAY MORNING. A
COLD FRONT THEN MOVES THROUGH ON WED CAUSING WINDS TO INCREASE FROM
THE NW. WINDS STAY STRONG AND VEER TO THE EAST THROUGH FRI AS TEH
NEXT SYSTEM WILL BEGIN TO DEVELOP NEAR THE TX COASTL BEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 51 49 63 56 / 10 40 60 70
BTR 55 54 66 58 / 10 50 60 80
MSY 58 55 69 62 / 10 30 50 70
GPT 56 52 66 59 / 0 20 40 60
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
