FXUS61 KCLE 270420
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
1120 PM EST THU NOV 26 2009
.SYNOPSIS...
LOW PRESSURE OVER NORTHERN LAKE HURON WILL SLOWLY MOVE OFF TO THE
EAST THROUGH FRIDAY PULLING A REINFORCING COLD FRONT ACROSS OUR AREA
TONIGHT. WEAK HIGH PRESSURE WILL MOVE UP THE OHIO VALLEY SATURDAY.
ANOTHER SERIES OF COLD FRONTS WILL MOVE THROUGH THE REGION SUNDAY
NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
NO BIG CHANGES MADE TO THE PREVIOUS FORECAST...MAINLY FRESHENED UP
THE WORDING. STILL SHOWED A MIXTURE RAIN AND SNOW CHANGING TO
MAINLY SNOW SHOWERS OVERNIGHT...EXCEPT NEAR THE LAKESHORE.
PREVIOUS DISCUSSION...A REINFORCING COLD FRONT CROSSING THE AREA
TONIGHT WILL PROVIDE A FOCUS TO CONVERGE MOISTURE AND CREATE LIFT
TO INDUCE PRECIPITATION DEVELOPMENT. COLDER AIR MOVING IN WITH THE
FRONT SHOULD CHANGE MOST OR ALL OF THE PRECIP FROM RAIN TO SNOW.
ADDED INSTABILITY FROM THE PRESENCE OF THE MID AND UPPER LOW OVER
LAKE ERIE WILL ADD INSTABILITY AND HELP TO GENERATE LAKE ENHANCED
SHSN FOR THE SNOWBELT. THE WARMER TEMPS LEADING INTO THE EVENT
SHOULD LIMIT SNOW ACCUMULATION AS TEMPS WILL STRUGGLE TO DROP TO
OR BELOW THE FREEZING POINT IN THE SNOWBELT TONIGHT. THIS WILL
ALLOW MOST OF THE SNOW TO MELT ON THE ROADWAYS EXCEPT WHEN HEAVIER
BURSTS OF SNOW OCCUR AT A RATE THAT IS BRIEFLY FASTER THAN THE
SNOW CAN MELT. IT SEEMS REASONABLE THAT UP TO AN INCH OF WET SNOW
MAY ACCUMULATE IN GRASSY AREAS OVER A GOOD PART OF THE CWA WITH
LOCALLY HIGHER AMOUNTS IN THE SNOWBELT. WARMER TEMPS ALONG THE
IMMEDIATE LAKESHORE WILL AFFECT PRECIP TYPE AND REDUCE OR
ELIMINATE ANY ACCUMULATION THERE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MOST OF THE SHSN SHOULD SHIFT INTO THE NE PART OF THE CWA FOR FRI
INTO FRI NIGHT WITH A TAPERING OF THE COVERAGE AND INTENSITY OF THE
SHSN BY LATER FRI NIGHT. THE LAST OF THE SHSN SHOULD BE ENDING SAT
MORNING AS THE MOISTURE IS SHOVED OFF TO THE EAST AS HIGH PRESSURE
RIDGING BUILDS INTO THE SNOWBELT BY MIDDAY. ACCUMULATION WILL
REMAIN QUESTIONABLE DUE TO TEMPS FRI ABOVE FREEZING ALONG WITH
PRECIP TYPE QUESTIONS. STILL SHOULD SEE SOME FAVORED HIGHER TERRAIN
AREAS SEE UP TO 3 INCHES LOCALLY OF ACCUMULATION ON GRASSY AREAS.
BELOW NORMAL TEMPS ON FRIDAY...WILL RECOVER TO BE CLOSER TO NORMAL
FOR SATURDAY FOR ALL BUT THE EASTERN PART OF THE SNOWBELT WHERE
READINGS MAY NOT GET OUT OF THE 30S.
HIGH PRESSURE WILL PROVIDE DRY WEATHER LATER SAT INTO SUN MORNING.
A FAST MOVING MID AND UPPER FLOW WILL QUICKLY BRING INCREASED
MOISTURE AND CLOUDS BACK FOR SUNDAY FROM WEST TO EAST. CHANCES FOR
RAIN WILL INCREASE SUN INTO SUNDAY NIGHT WITH THE PASSAGE OF A COLD
FRONT PROVIDING INCREASED CONVERGENCE AND LIFT. TEMPS PROBABLY WILL
GET COLD ENOUGH LATE SUNDAY NIGHT FOR CHANGE TO SNOW.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
COLD POOL EXPECTED TO SLIDE SOUTHEAST INTO THE AREA IN THE WAKE OF
THE COLD FRONT. LEFTOVER LAKE EFFECT SHOWERS EXPECTED TO CONTINUE
ON MONDAY BUT THEN CHANCES DROP OFF TO SLIGHT CHANCE THAT WILL
CONTINUE INTO TUESDAY. HIGH PRESSURE SLIDES IN FROM THE SOUTHWEST
AND FLOW MAY TAKE A WHILE TO PUSH LEFTOVER MOISTURE OUT OF THE AREA.
HIGH PRESSURE DOMINATES THE REGION ON WEDNESDAY.
MODELS ARE IN AGREEMENT WITH DEVELOPING A LOW PRESSURE SYSTEM OVER
THE GULF COAST REGION AND MOVING THE STORM SYSTEM UP THE COAST. THE
DIFFERENCE IS THE INTENSITY OF THE LOW AND EXTENT IT REACHES BACK TO
THE WEST. GFS KEEPS THE LOW EXCLUSIVELY ALONG THE COAST SPILLING
BACK SOME CLOUDS FROM THE WEST. EUROPEAN HAS A HISTORY OF TRACKING
LOW EAST ACROSS THE GREAT LAKES AND THEN BECOME ABSORBED IN THE
COASTAL STORM. EUROPEAN ALSO HAS THE LOW TRACK MUCH FURTHER WEST.
I DECIDED TO SPLIT THE DIFFERENCE AND STILL KEEP A MENTION OF
PRECIPITATION GOING IN THE LATTER PERIODS OF THE FORECAST. MODELS
DO INDICATE AIR WITH THIS SYSTEM SHOULD BE WARM ENOUGH ALOFT TO KEEP
PRECIPITATION FOR THE MOST PART RAIN.
GRADUAL DROP IN TEMPERATURES THROUGH THE COURSE OF THE EXTENDED
PERIODS AS SLIGHTLY COLDER AIR BEGINS TO WORK EAST ACROSS THE
REGION.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
COLD FRONT ON TOP OF MFD...WILL MOVE ACROSS THE ENTIRE FORECAST AREA
BY DAYBREAK. PRECIPITATION IS STILL PREDOMINATELY RAIN...DO NOT
EXPECT MUCH IN THE WAY OF SNOW BEFORE 09Z. BEST CHANCE FOR SNOW
WILL BE IN THE SNOW BELT EAST OF CLEVELAND AS 850 MB TEMPS DROP TO
MINUS 6C TO MINUS 8C BY 12Z AND LAKE EFFECT BEGINS TO SET UP.
ALTHOUGH CEILINGS RANGE FROM IFR TO VFR ACROSS THE AREA EXPECT
PREDOMINATLEY MVFR CIGS OVERNIGHT.
.OUTLOOK...EXPECT MVFR CIGS TO LINGER INTO THE AFTERNOON HOURS
FRIDAY. CLOUDS WILL BEGIN TO ERODE AND IMPROVE TO VFR FROM THE
WEST TOMORROW NIGHT. EXPECT VFR CONDITIONS TO CONTINUE SATURDAY
AND SATURDAY NIGHT. NEXT COLD FRONT EXPECTED THROUGH SUNDAY
AFTERNOON OR EVENING. PRECIPITATION WILL START AS ALL RAIN...AND
EVENTUALLY TRANSITION TO SNOW SUNDAY NIGHT OR MONDAY. MODELS STILL
NOT IN GOOD AGREEMENT ON THE TIMING OF THE COLDER AIR AT THIS
TIME.
&&
.MARINE...
WILL NEED TO ISSUE A SMALL CRAFT ADVISORY WITH THIS FORECAST GIVEN
THE EXPECTED INCREASE IN THE SURFACE PRESSURE GRADIENT AND COOLING
ALOFT WHICH WILL ALLOW STRONGER WINDS TO MIX TO THE SURFACE AS A
WEAK COLD FRONT MOVES ACROSS THE LAKE THIS EVENING. MODERATE
NORTHWEST FLOW OF 15 TO 25 KNOTS WILL DEVELOP AFTER FRONTAL PASSAGE
AND PERSIST UNTIL EARLY SATURDAY WHEN HIGH PRESSURE WILL BUILD INTO
THE REGION. WINDS WILL LIKELY REMAIN BELOW SCA CRITERIA FROM LATE
SATURDAY UNTIL SUNRISE TUESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST SATURDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS/RANDEL
SHORT TERM...ADAMS
LONG TERM...LOMBARDY
AVIATION...DJB
MARINE...REL
