603
FXUS64 KLIX 170243
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
943 PM CDT SAT OCT 16 2021
EVENING UPDATE
STRONG GRADIENT FLOW WILL PERSIST OVER THE
COASTAL WATERS TONIGHT, AND THE SMALL CRAFT ADVISORY WILL REMAIN
IN EFFECT FOR ALL OF THE WATERS THROUGH THE OVERNIGHT HOURS. BASED
ON RECENT OBSERVATIONS, WINDS ARE RUNNING SLIGHTLY HIGHER THAN THE
FORECAST, AND HAVE INCREASED WIND SPEEDS OVER THE MARINE ZONES BY
2 TO 3 KNOTS ON AVERAGE. OUTSIDE OF THE STRONGER WINDS OVER THE
WATERS, ALL OF THE FORECAST PARAMETERS ARE ON TRACK THIS EVENING.
PG
PREV DISCUSSION
/ISSUED 613 PM CDT SAT OCT 16 2021/
AVIATION (06Z TAF DISCUSSION)...VFR CONDITIONS WILL REMAIN IN
PLACE AT ALL OF THE TERMINALS THROUGH TOMORROW EVENING DUE TO
CONTINUED DEEP LAYER RIDGING OVER THE GULF SOUTH. WINDS WILL
REMAIN GUSTY FROM THE NORTH AT KNEW, KMSY, KHUM, AND KGPT THROUGH
TOMORROW MORNING WITH SOME GUSTS OF 20 TO 25 KNOTS POSSIBLE AT
KNEW AND KMSY. PG
PREV DISCUSSION... /ISSUED 322 PM CDT SAT OCT 16 2021/
SYNOPSIS...
UPPER TROUGH CROSSING THE APPALACHIAN MOUNTAINS THIS AFTERNOON
WITH RIDGING BUILDING OVER THE ROCKIES. AT THE SURFACE, LOW
PRESSURE OVER QUEBEC CANADA HAS A COLD FRONT THROUGH PENNSYLVANIA
TO THE WESTERN CAROLINAS TO OUR FAR SOUTHEASTERN COASTAL WATERS.
HIGH PRESSURE WAS CENTERED OVER WESTERN OKLAHOMA. NO PRECIPITATION
NOTED ON RADAR, AND REALLY THE ONLY CLOUDS TO SPEAK OF ARE SOME
CIRRUS TO THE SOUTH OF INTERSTATE 10. MID AFTERNOON TEMPERATURES
WERE GENERALLY IN THE LOWER AND MID 70S, WITH DEW POINTS RANGING
FROM NEAR 40 NORTHWEST TO LOWER 50S SOUTHEAST.
SHORT TERM (THROUGH TUESDAY)...
THE OKLAHOMA HIGH PRESSURE WILL MOVE SLOWLY EASTWARD OVER THE NEXT
3 DAYS, ALONG WITH THE UPPER RIDGE. LOW LEVEL FLOW MAINTAINS AN
OFFSHORE COMPONENT THROUGH TUESDAY, SO NO SIGNIFICANT INCREASE IN
MOISTURE. A WEAK SOUTHERN STREAM SHORTWAVE RIDING OVER THE RIDGE
MOVES ACROSS THE AREA DURING THE DAY MONDAY, BUT ISN'T EXPECTED TO
PRODUCE ANY MORE THAN HIGH CLOUDS.
DON'T REALLY SEE ANY REASON TO MAKE SIGNIFICANT ADJUSTMENTS TO
HIGH TEMPERATURES IN THE SHORT RANGE PORTION OF THE FORECAST. NOT
A LOT OF SPREAD IN THE HIGH TEMPERATURE NUMBERS, AND NBM EDGES
TOWARD THE WARMER END OF THE ENVELOPE WHERE DIFFERENCES OCCUR.
OVERNIGHT LOWS ARE A BIT OF A DIFFERENT STORY. NBM NUMBERS THE
NEXT COUPLE OF NIGHTS ARE SIGNIFICANTLY WARMER THAN THOSE FROM THE
GFS/ECMWF. CURRENT DEW POINTS WOULD CERTAINLY SUPPORT LOWS SUNDAY
MORNING CLOSER TO THE GFS/ECMWF NUMBERS, BUT THERE'S SOME QUESTION
WHETHER WINDS WILL DECOUPLE LONG ENOUGH TO RADIATE DOWN TO THOSE
LEVELS. PLAN TO DRIFT A DEGREE OR TWO BELOW THE NBM DETERMINISTIC
NUMBER, BUT NOT NEARLY AS LOW AS THE OPS GUIDANCE. TOMORROW NIGHT,
THE ISSUE ISN'T EXPECTED TO BE WIND, BUT CLOUD COVER. GUIDANCE HAS
BEEN HIGHLIGHTING FOR A COUPLE OF DAYS A LAYER OF MOISTURE BETWEEN
200-300 MB THAT WOULD RESULT IN A FAIRLY DENSE CIRRUS SHIELD IN
ADVANCE OF THE SHORTWAVE THAT MOVES ACROSS THE AREA MONDAY. AGAIN
PLAN ON GOING WARMER THAN THE GFS/ECMWF NUMBERS, BUT A SHADE BELOW
NBM DETERMINISTIC. NUMBERS ARE A BIT CLOSER MONDAY NIGHT, SO NO
BIG ADJUSTMENTS NEEDED. 35
LONG TERM (TUESDAY NIGHT AND BEYOND)...
MAIN TROUGHING REMAINS IN THE NORTHERN STREAM FOR MUCH OF NEXT
WEEK. WITH THE DEPARTURE OF MONDAY'S SHORTWAVE, THE SOUTHERN
STREAM JET SHIFTS A BIT OFFSHORE FOR WEDNESDAY AND THURSDAY. A
NORTHERN STREAM SHORTWAVE MOVING THROUGH THE GREAT LAKES WILL PUSH
A COLD FRONT INTO THE AREA THURSDAY NIGHT OR FRIDAY, BUT UNTIL
THEN, SHORTWAVES MOVING THROUGH THE SOUTHERN STREAM AREN'T GOING
TO HAVE MUCH MOISTURE TO WORK WITH.
CERTAINLY CAN'T RULE OUT SOME RAIN SHOWERS DURING THE DAYTIME
HOURS WEDNESDAY AND THURSDAY, BUT AMOUNTS WILL BE LIGHT, AND BEST
RAIN CHANCES (30-50%) WOULD BE ACROSS SOUTHERN PORTIONS OF THE
AREA. IF THE JET SHIFTS A LITTLE FURTHER SOUTH THAN ANTICIPATED,
MOST OR ALL OF THE AREA COULD REMAIN DRY NEXT WEEK. IN FACT, DON'T
SEE ANY REAL WEATHER MAKERS THROUGH NEXT WEEKEND.
DON'T PLAN ON MAKING SIGNIFICANT CHANGES TO LONGER TERM
TEMPERATURE GUIDANCE. NBM VALUES ALREADY SHADE TOWARD THE WARMER
ECMWF NUMBERS. 35
AVIATION...
FRONT HAS MOVED WELL OFF THE COAST, AS HAVE ANY LOWER CLOUDS.
CEILINGS AND VISIBILITIES EXPECTED TO REMAIN VFR THROUGH THE
FORECAST PERIOD. ONLY REAL CONCERN IS WINDS. NORTHERLY GUSTS TO 25
KNOTS POSSIBLE AT ALL TERMINALS UNTIL CLOSER TO SUNSET, WHICH WILL
PRODUCE CROSSWIND PROBLEMS ON EAST-WEST RUNWAY CONFIGURATIONS.
BEYOND 00Z, WINDS SHOULD DROP BELOW 10 KNOTS AT MOST SITES, WITH
THE EXCEPTION OF THE NEW ORLEANS TERMINALS DOWNWIND OF LAKE
PONTCHARTRAIN (KNEW/KMSY). WIND GUSTS ABOVE 20 KNOTS LIKELY TO
CONTINUE MOST OR ALL NIGHT AT KNEW BEFORE DROPPING OFF. 35
MARINE...
DO NOT PLAN TO MAKE ANY CHANGES TO SMALL CRAFT ADVISORY PARAMETERS
AT THIS TIME. WILL GO WITH SMALL CRAFT EXERCISE CAUTION HEADLINE
FOR THE TIDAL LAKES AND MISSISSIPPI SOUND AFTER THEIR ADVISORY
EXPIRES AT 03Z. EVENING SHIFT MAY OPT TO EXTEND THE ADVISORY, BUT
WILL LEAVE THAT TO THEIR CALL. THE OPEN WATERS WILL PROBABLY NEED
A HEADLINE BEYOND THEIR ADVISORY EXPIRATION AT 15Z TOMORROW, AS
WELL. ONCE CONDITIONS RELAX BELOW 15 KNOTS SUNDAY NIGHT OR MONDAY,
THE OPEN WATERS ARE LIKELY TO STILL HAVE 10 TO 15 KNOT WINDS FOR
MUCH OF THE TIME INTO AT LEAST MID-WEEK. 35
PRELIMINARY POINT TEMPS/POPS
MCB 46 73 48 75 / 0 0 0 0
BTR 47 73 49 76 / 0 0 0 0
ASD 47 75 50 76 / 0 0 0 0
MSY 58 74 59 76 / 0 0 0 0
GPT 50 75 52 75 / 0 0 0 0
PQL 48 73 51 75 / 0 0 0 0
LIX WATCHES/WARNINGS/ADVISORIES
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR GMZ530-532-534-
536-538-550-552-555-557-570-572-575-577.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR GMZ532-534-536-
538-550-552-555-557-570-572-575-577.
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