678
FXUS63 KLMK 202303
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
603 PM EST WED FEB 20 2019
..UPDATED AVIATION DISCUSSION
FORECAST UPDATE
ISSUED 500 PM EST WED FEB 20 2019
THE FLOOD WATCH HAS BEEN CANCELLED A LITTLE AHEAD OF SCHEDULE AS THE
HEAVIEST RAINS HAVE PUSHED WELL EAST OF THE AREA, AND CALLS TO
SEVERAL COUNTIES HAVE REVEALED SOME IMPROVING CONDITIONS IN REGARDS
TO FLOODED ROADWAYS. WATER LEVELS WILL STILL REMAIN HIGH ALONG
CREEKS, STREAMS, AND RIVERS THROUGH THE END OF THE WEEK.
SHORT TERM
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 227 PM EST WED FEB 20 2019
THE SURFACE BOUNDARY THAT ENTERED WESTERN KENTUCKY THIS AFTERNOON
WILL CONTINUE TO MOVE EASTWARD ACROSS CENTRAL KENTUCKY AND SOUTHERN
INDIANA THIS EVENING, PUSHING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS AHEAD OF IT. THE REGION SHOULD BE FREE OF RAIN BY
MIDNIGHT. CLOUDS WILL LIKELY LINGER THROUGH THE NIGHT, THOUGH, AS
MOISTURE GETS TRAPPED UNDER A SHARP INVERSION. A FEW PATCHES OF
DRIZZLE AREN'T OUT OF THE QUESTION, ESPECIALLY IN THE BLUE GRASS.
LOW TEMPERATURES WILL MOSTLY BE IN THE MIDDLE 30S, BUT A FEW SPOTS
IN SOUTHERN INDIANA MAY DIP INTO THE LOWER 30S, ESPECIALLY IF THE
CLOUDS BREAK UP SOONER THAN EXPECTED.
THOUGH RAINFALL AMOUNTS WILL BE RELATIVELY LIGHT THIS EVENING, THERE
ARE MANY SPOTS AROUND THE AREA THAT ARE STILL WAITING FOR EARLIER
MINOR FLOODING TO RECEDE, SO WILL HOLD ON TO THE FLOOD WATCH WHILE
THE RAIN IS STILL FALLING. THE WATCH WILL BE CLEARED EARLY FROM WEST
TO EAST AS THE FRONT PASSES THROUGH.
TOMORROW HIGH PRESSURE NOSING IN FROM THE MIDWEST WILL GIVE US A
MUCH WELCOME BREAK FROM THE WET AND UNSETTLED WEATHER. WE SHOULD
ACTUALLY SEE SOME PARTIAL SUNSHINE WITH A LIGHT BREEZE AND
SEASONABLE HIGHS IN THE UPPER 40S AND LOWER 50S.
LONG TERM
(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 PM EST WED FEB 20 2019
..ADDITIONAL HEAVY RAINFALL AND THUNDERSTORMS THIS WEEKEND
THURSDAY'S DRY WEATHER WILL BE SHORT-LIVED AS RAIN MOVES BACK INTO
SOUTHERN KENTUCKY THURSDAY EVENING, THEN DRIFTS NORTH TOWARD THE
OHIO RIVER BY FRIDAY MORNING. THIS IS IN RESPONSE TO RIPPLES MOVING
THROUGH THE SOUTHWEST FLOW ALOFT, AND AMOUNTS WILL BE LIGHT DUE TO
LOW LEVEL NORTHEAST FLOW AROUND A SURFACE HIGH DRIFTING EASTWARD
ACROSS THE GREAT LAKES REGION.
HOWEVER, HOT ON THE HEELS OF THIS WEAK SYSTEM, A VIGOROUS TROF OVER
THE SOUTHWEST U.S. WILL MAKE ITS PRESENCE KNOWN FOR THE WEEKEND. AS
A SURFACE LOW DEVELOPS OVER THE SOUTHERN PLAINS AHEAD OF THE DIGGING
UPPER TROF, THE GULF OPENS BACK UP, PRIMING THE LOWER ATMOSPHERE
WITH MOISTURE TO COMBINE WITH MID AND UPPER MOISTURE AND ENERGY
MOVING IN AS THE UPPER SYSTEM MOVES INTO THE MISSISSIPPI VALLEY
SATURDAY. THIS TIGHTLY WOUND SYSTEM WILL BRING STRONG SOUTHERLY
WINDS TO THE AREA THAT WILL NOT ONLY SEND TEMPERATURES INTO THE 60S
ACROSS THE AREA, BUT DEW POINTS INTO THE 50S AND LOWER 60S AS WELL.
WITH THE AIRMASS SATURATED FROM THE SURFACE THROUGH 40K FEET,
RAINFALL RATES WILL BE HIGH AT TIMES, BUT THE THICK CLOUDS WILL ALSO
WORK TO LIMIT INSTABILITY SOMEWHAT, PREVENTING ANY INSOLATION TO
HEAT THE SURFACE. CURRENT GUIDANCE SHOWS A WEAK THERMAL CAP AT
850MB, WHICH COULD SUPPRESS THUNDER DEVELOPMENT SOMEWHAT, BUT WITH
THE STRONG LOW LEVEL JET IN PLACE - AND A 140KT JET ALOFT, SYNOPTIC
FORCING COULD OVERCOME THIS CAP. IF THAT HAPPENS, NOT ONLY WILL
THERE BE THE THREAT FOR TORRENTIAL RAINFALL, BUT FOR SEVERE
THUNDERSTORMS SATURDAY AS 60KT WINDS LOOK TO BE JUST A FEW THOUSAND
FEET ABOVE THE SURFACE, AND ANY MIXING DOWN WOULD WREAK HAVOC ON
TREES ALREADY STRUGGLING TO STAND IN THE QUICKSAND-LIKE TOPSOIL
ACROSS THE AREA. FORTUNATELY, WITH NO LEAVES YET ON THE TREES, THEY
WON'T HAVE THAT ADDED WEIGHT AND WIND RESISTANCE TO WORSEN THE
SITUATION.
THE CENTER OF BOTH THE SURFACE AND UPPER LOW WILL MOVE INTO THE
GREAT LAKES BY SUNDAY MORNING, AND RAIN WILL END ACROSS THE AREA
WITH A TRAILING COLD FRONT MOVING THROUGH WITH IT. A RARE SET OF DRY
DAYS FOLLOW WITH NEARLY ZONAL UPPER LEVEL FLOW BEFORE THE NEXT
CHANCE OF RAIN RETURNS WEDNESDAY. THIS FAR OUT, HOWEVER, IT REMAINS
TO BE SEEN EXACTLY HOW SIGNIFICANT THIS WILL BE, WITH THE MAJOR MID-
LONG RANGE MODELS ALL DOING THEIR OWN THINGS BY THEN.
TEMPERATURE-WISE THROUGH THE PERIOD, HIGHS WILL BE IN THE 50S FRIDAY
BEFORE WARMING INTO THE 60S SATURDAY, THEN DROP BACK INTO THE 50S
SUNDAY AND THE 40S MONDAY BEFORE REBOUNDING. LOW TEMPERATURES WILL
BE IN THE 30S TO LOWER 40S THURSDAY NIGHT, THEN STAY ABOVE 40
THROUGH SUNDAY NIGHT, WHEN THEY WILL DROP BACK INTO THE 20S BEFORE
RETURNING TO THE 30S FOR THE REMAINDER OF THE PERIOD.
AVIATION
(00Z TAF ISSUANCE)
UPDATED AT 600 PM EST WED FEB 20 2019
SHOWERS AHEAD OF A FRONT ARE BEGINNING TO PUSH EAST OF THE I-65
CORRIDOR, AND SHOULD PUSH PAST THE I-75 CORRIDOR OVER THE THE NEXT
SEVERAL HOURS. POST-FRONTAL STRATUS WILL LINGER THROUGH THE
OVERNIGHT HOURS, WITH GRADUAL CLEARING OCCURRING FROM WEST TO EAST.
AREAS NEAR THE I-75 CORRIDOR MAY NOT SEE CLEARING UNTIL AFTER
SUNRISE TOMORROW.
ONE LOW-CONFIDENCE CONCERN FOR TONIGHT IS THE FOG POTENTIAL WEST OF
I-65. MOST GUIDANCE DOES NOT DEVELOP FOG, BUT SOME (LIKE THE NAM)
HIT DENSE FOG REALLY HARD OVERNIGHT IN AREAS THAT SEE CLEARING.
THINK WINDS WILL STAY UP ENOUGH OVERNIGHT BEHIND THE FRONT TO KEEP
THE LOWER BOUNDARY LAYER MIXED ENOUGH TO KEEP FOG FROM BEING TOO
MUCH OF AN ISSUE. THIS WILL BE MONITORED IN SUBSEQUENT FORECAST
UPDATES.
LMK WATCHES/WARNINGS/ADVISORIES
IN...NONE.
KY...NONE.
UPDATE...DM
SHORT TERM...13
LONG TERM...JBS
AVIATION...DM
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