Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 01/28/07

.SYNOPSIS...UPPER LEVEL LOW PRESSURE AND ONSHORE FLOW WILL BRING COOLER DAYS. COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS...EXTENDING LOCALLY INLAND. THE UPPER LOW COULD CAUSE A FEW LIGHT SHOWERS IN ORANGE AND SAN BERNARDINO COUNTIES SATURDAY NIGHT INTO SUNDAY MORNING. PARTLY CLOUDY EARLY NEXT WEEK. DRIER NORTHWEST FLOW ALOFT TOWARD THE END OF NEXT WEEK FOR LESS CLOUDINESS AND A LITTLE WARMER DAYS.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

.SHORT TERM (TODAY-MON)...THERE WERE AREAS OF STRATUS IN THE COASTAL WATERS BEGINNING TO MOVE ONSHORE THIS AFTERNOON. MOSTLY CLEAR SKIES ELSEWHERE. ACARS SOUNDINGS INDICATED A WEAK INVERSION BASED NEAR 1200 FT. WEAK ONSHORE GRADIENTS AND ONSHORE TRENDS.

A CLOSED UPPER LOW OFF THE NORTHERN CA COAST WILL HAVE VERY LITTLE SRN PROGRESSION AND WILL EVENTUALLY BE ABSORBED BY A LARGER TROUGH TO THE NW. THIS WILL MAINTAIN WEAK CYCLONIC FLOW OVER SRN CA THROUGH SAT WITH WEAK RIDGING SUN AND THEN FLAT WLY FLOW MON. MOISTURE CIRCULATING AROUND THIS LOW COULD BRING A FEW LIGHT SHOWERS TO ORANGE AND SAN BERNARDINO COUNTIES SAT NIGHT INTO SUN MORNING. THE SYNOPTIC SCALE GRADIENTS WILL REMAIN WEAKLY OFFSHORE BUT LOCAL ONSHORE GRADIENTS TO THE E WILL INCREASE THROUGH SAT AND THEN WEAKEN A LITTLE SUN AND MON. THERE WILL ALSO BE AN EDDY TONIGHT. THIS WILL CAUSE MORE COASTAL LOW CLOUDS AND FOG THIS AFTERNOON THROUGH SAT MORNING. THERE COULD BE LOCAL DENSE FOG AS THE STRATUS PUSHES INLAND. THE MARINE LAYER SHOULD DECREASE A BIT SAT NIGHT AND SUN NIGHT...HOWEVER THERE WILL BE MORE MID AND HIGH CLOUDS IN SW FLOW ALOFT FOR PARTLY CLOUDY SKIES. COOLER DAYS IN MOST AREAS...ESPECIALLY SAT AND MON. MORE CLOUDS AND HIGHER HUMIDITIES WILL MODERATE MIN TEMPS.

.LONG TERM (TUE-FRI)...A LITTLE STRONGER TROUGH MAY MOVE THROUGH TUE OR WED. PARTLY CLOUDY SKIES WITH NEAR OR A LITTLE BELOW SEASONAL MAX TEMPS DURING THIS PERIOD. THERE WILL ALSO BE SMALL CHANCES OF PRECIP BUT TOO LOW TO MENTION IN THE EXTENDED PERIOD. DRIER N TO NW FLOW ALOFT AND INCREASING HEIGHTS FOR LESS CLOUDS AND A LITTLE WARMER DAYS.

&&

.AVIATION... THE COASTAL EDDY WILL LIKELY PERSIST INTO SATURDAY. THE STRATUS HAS BURNED OFF OVER LAND BUT SOME AREAS REMAIN OVER THE COASTAL WATERS. CEILINGS ARE EXPECTED TO RETURN TO THE COASTAL TAF SITES LATE THIS AFTERNOON AND MOVE INLAND IN SOME AREAS OVERNIGHT. CEILINGS WILL INITIALLY BE 500-1200 FEET BETWEEN 23-02Z. VISBYS WILL BE 3-5SM AT THE LOWEST. EXPECT LOW CLOUDS ALL NIGHT AND A RISE IN CEILINGS AND VISBYS BY SAT MORNING. THE CEILINGS ARE EXPECTED TO SCATTER OUT AROUND 17-19Z SATURDAY. ABOVE THE MARINE LAYER...VFR CONDITIONS CONTINUE.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...DVA AVIATION...MM/PG

.EVENING UPDATE...

SNOW SHOWERS HAVING A HARD TIME MATERIALIZING IN THE WESTERN COUNTIES THIS EVENING. HAVE BACKED OFF THE POPS OVERNIGHT AND DON`T EXPECT MUCH ACCUMULATING SNOW TIL AFTER DAYBREAK ALONG THE ALLEG FRONT. ELSEWHERE HAVE INDICATED A FEW RAIN SHOWERS OVERNIGHT BUT NO MORE THAN A FEW HUNDREDTHS ON AN INCH EAST OF THE BLUE RIDGE. HAVE ALSO BUMPED OVERNIGHT TEMPS UP A FEW DEGS...PARTIALLY AS DAYTIME TEMPS WERE NEAR 60 AND ALSO THE COLD AIR WILL BE SLOW TO WORK INTO THE EASTERN COUNTIES.

LOCATIONS WEST OF THE I-95 CORRIDOR COULD SEE A FEW WET FLAKES MIXED IN OVERNIGHT BUT AGAIN NO ACCUM EXPECTED THERE.

UPSLOPE ENHANCED SNOW EVENT STILL ON TARGET FOR OUR WESTERN COUNTIES...BEGINNING SUNDAY AND CONTINUING INTO MONDAY. LOOKS LIKE MORE INTENSE SNOW ARRIVES LATE DURING THE DAYTIME THEREFORE WILL ALLOW THE MID CREW TO HOIST WHAT WOULD BE A LATE FIRST PERIOD SNOW ADVISORY IF NECESSARY. OUR CURRENT FCST CONTINUES TO INDICATE A HIGHEND ADVISORY EVENT IN THE FAR WEST...WHICH COULD BREAK INTO WARNING CRITERIA AND WILL NEED TO BE RE-EVALUATED FOR THAT POTENTIAL.

STILL EXPECT LIGHT WINDS ON THE WATERS OVERNIGHT. SCA WINDS DEVELOPING ON SUNDAY AS NW FLOW DEVELOPS... A SCA REMAINS IN PLACE ON SUNDAY FOR THIS REASON.

JB

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/... WATER VAPOR LOOP SHOWS AN UPPER LOW LIFTING THROUGH THE PLAINS AS THE SOUTHERN BRANCH JET PUNCHES INTO THE GULF STATES (WITH COPIOUS MOISTURE ALOFT). THIS IS AHEAD OF THE NORTHERN STREAM WAVE DIGGING INTO THE UPPER MIDWEST. A RIDGE IS OVER THE EASTERN CONUS. ACARS 400-250MB WIND OBSERVATIONS REVEAL SOUTHWESTERLY 100-120KT JET FROM THE MIDWEST THROUGH NEW ENGLAND. A 120-160KT SOUTHWESTERLY JET EXTENDED FROM MEXICO THROUGH THE GULF STATES. 11Z SURFACE ANALYSIS PLACED A 990MB OCCLUDED CYCLONE ACROSS THE UPPER GREAT LAKES...WITH THE OCCLUDED FRONTAL BOUNDARY STRETCHED SOUTHEAST TO NEAR DETROIT...THEN SOUTHWEST AS A COLD FRONT THROUGH THE PLAINS. A STATIONARY BOUNDARY EXTENDED EAST FROM THE TRIPLE POINT ACROSS SOUTHERN NEW ENGLAND (WITH A 1014MB ARCTIC HIGH ACROSS QUEBEC). A FRONTAL BOUNDARY WHICH DEVELOPED OVERNIGHT IS MOVING NORTHEAST AS A WARM FRONT FROM ERIE PENNSYLVANIA SOUTHEAST TO NEAR CHARLOTTESVILLE...THEN EAST ACROSS THE DELMARVA. A TROUGH WAS NOTED IN THE LEE OF THE APPALACHIANS.

EXPECT STRATO-CU TO BUILD SOUTH AS WARM ADVECTION CONTINUES WITH COOLING ATOP THE BOUNDARY LAYER AFTER SUNSET. MEANWHILE...MID LEVEL MOISTURE CONTINUES TO STREAM NORTHEAST TOWARD THE MID ATLANTIC AS THE UPPER LEVEL RIDGE AMPLIFIES IN ADVANCE OF THE NEXT NORTHERN STREAM WAVE. THIS IS CAUSING THE UPPER LOW ACROSS THE PLAINS TO WEAKEN AND ERODE INTO PIECES DOWNSTREAM.

BULK OF PRECIPITATION SEEN ON NATIONAL RADAR LOOP WILL REMAIN SOUTH OF THE SOUTHERN STREAM JET...ACROSS THE GULF STATES AND SOUTH CAROLINA. OUR PRECIPITATION CHANCES REST ON THE SHEAR AXIS DEVELOPED AHEAD OF THE NORTHERN STREAM WAVE...CURRENTLY PRODUCING LIGHT PRECIPITATION (T OR .01 VIA METARS) FROM SOUTHERN ILLINOIS INTO OHIO VALLEY. BELIEVE THE GFS (AND GFS MOS) IS OVERPLAYING CHANCES OF SEEING PRECIPITATION...AND LEANED TOWARD THE DRIER NGM/NAM/LWX WRF-NMM. THERMAL PROFILES WOULD ORIGINALLY FAVOR RAIN...BUT WITH COOLING BEFORE SUNRISE...COULD SUPPORT SNOW EAST INTO THE METRO AREA. GIVEN THE LOW PROBABILITY OF ANY PRECIPITATION...LOW QPF...AND MARGINAL THERMAL PROFILES...AM NOT TOO CONCERNED ABOUT SNOW ACCUMULATION EAST OF THE HIGHER TERRAIN OF THE ALLEGHENY FRONT.

ALONG AND WEST OF THE ALLEGHENY FRONT IS A DIFFERENT STORY. UPSLOPE PRECIPITATION COULD ACCUMULATE AS SNOW AS COLD ADVECTION BEGINS LATER TONIGHT BEHIND THE COLD FRONTAL PASSAGE. 09Z SHORT RANGE ENSEMBLES INDICATE BETWEEN 0.15-0.30" OF LIQUID EQUIVALENT THROUGH SUNDAY. HAVE PLACED 1-2" OF SNOW IN THE FORECAST FOR UPSLOPE REGION (WITH GOOD AGREEMENT FROM NEIGHBORS AND HPC AS WELL). AN ADVISORY WOULD LIKELY BE NEEDED SUNDAY BEFORE THE SNOW INTENSIFIES SUNDAY EVENING. WINDS WILL CONTINUE TO GUST 25-30 MPH.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... A BUSY EXTENDED FORECAST ON TAP.

BY 00Z MONDAY...LONGWAVE TROUGH AND ASSOCIATED STRONG SHORTWAVE ENERGY COMING THROUGH THE CWFA. THE TROUGH SHOULD BE EAST OF THE CWFA BY EARLY MONDAY. ZONAL FLOW RETURNS TO THE AREA LATE ON MONDAY. A SECOND STRONG SHORTWAVE COMES THROUGH ON TUESDAY. ZONAL FLOW WILL BE THE RULE UNTIL FRIDAY WHEN THE FLOW TURNS MORE SOUTHWEST AS A TROUGH DIGS OVER THE MIDDLE PART OF THE COUNTRY.

SURFACE LOW PRESSURE IS OFF THE COAST BY SUNDAY NIGHT WITH UPSLOPE FLOW OCCURRING OVER THE WESTERN RIDGES. IN ADDITION...THE GFS IS HINTING AT SOME BANDING OVER NORTHEAST MD AGAIN ON THE BACKSIDE OF THE LOW CENTER. THE UPSLOPE SNOW SHOWERS SHOULD CUT OFF EARLY ON MONDAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTH. A FROPA IS EXPECTED ON TUESDAY. THE GFS IS STILL KEEPING MOST OF THE PRECIP OVER THE WESTERN THIRD OF THE CWFA. HIGH PRESSURE ONCE AGAIN BUILDS IN FROM THE SOUTH ON WEDNESDAY THROUGH THURSDAY. BY LATE FRIDAY INTO SATURDAY...ANOTHER COLD FRONT IS EXPECTED. IN ADDITION...A COASTAL LOW IS PROGGED TO DEVELOP OFF THE MID ATLANTIC COAST.

THE MOST ACTIVE PERIOD IN THE LONG TERM IS EXPECTED TO BE SUNDAY NIGHT AS THE STRONG SHORTWAVE DIVES DOWN FROM CANADA. BOTH THE GFS AND NAM ARE PROGGING GOOD QPF ALONG THE WESTERN RIDGES WITH THIS SYSTEM. HAVE UPPED THE POPS TO LIKELY IN THIS AREA...WITH SNOWFALL ACCUMULATIONS AROUND FOUR INCHES FOR SUNDAY NIGHT PROGGED BY BOTH THE NAM AND GFS. IN ADDITION...THE GFS IS HINTING AT SOME BANDING OF PRECIP OVER THE NE MARYLAND FOR OVERNIGHT SUNDAY. HAVE GONE AHEAD AND PUT SOME HIGHER POPS/QPF IN THIS REGION. SINCE THE BANDING WILL BE HARD TO NAIL DOWN...ESPECIALLY THIS FAR OUT...WILL ONLY ADD SOME SLIGHTLY HIGHER QPF THAN PROGGED.

WINDS WILL ALSO BE GUSTY LATE SUNDAY NIGHT INTO MONDAY ON THE BACKSIDE OF THE SURFACE LOW. BUFKIT SOUNDINGS KEEP THE GUSTS BLO WIND ADVISORY CRITERIA FOR NOW...BUT MODELS CAN UNDERESTIMATE THE WINDS.

PRETTY MUCH FOLLOWED GUIDANCE THROUGH SATURDAY. THIS DIDN`T CAUSE MUCH OF A CHANGE FOR THE REMAINDER OF THE EXTENDED.

&&

.AVIATION... SOUTHWESTERLY WINDS SLACKEN WITH SUNSET AS STRATO CU INVADES FROM THE NORTH AND NORTHWEST...AND MID LEVEL MOISTURE ADVECTS IN FROM THE SOUTHWEST. LEFT MENTION OF PRECIPITATION OUT OF TERMINALS AS PROBABILITY OF MEASUREMENT AND VISIBILITY RESTRICTION IS LOW.

&&

.MARINE... SMALL CRAFT ADVISORY IN EFFECT TODAY. OBSERVED WIND GUSTS IN THE MOUNTAINS ARE BETWEEN 25-31KTS. OBSERVED WINDS BETWEEN 900-950MB ARE 25-30KTS ON THE 12Z KIAD RAOB AND MORNING ACARS SOUNDINGS. EXPECT MOST OF THIS MOMENTUM WILL BE ABLE TO BREAK THE MARINE INVERSION (WATER TEMPERATURES ARE 39F...AIR TEMPERATURES OVER THE WATERS EXPECTED IN THE MID 40S). DEEPER MIXING IS EXPECTED TO REACH THE NORTHERN BAY BEFORE SUNSET.

12Z ETA/MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS SLACKEN TO LESS THAN 10KT OVERNIGHT...BEFORE INCREASING TO 10-13KTS TOMORROW. 12Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS SHOW ADDITIONAL MOMENTUM TRANSFER OF 18-20KTS POSSIBLE SUNDAY.

SMALL CRAFT CONDITIONS...MAINLY FOR GUSTS...WILL BE ONGOING FOR SUNDAY NIGHT. AS THE GRADIENT TIGHTENS THE WIND SPEED AND GUSTS WILL INCREASE RAPIDLY LATE SUNDAY NIGHT. A GALE WARNING WILL BE LIKELY LATE SUNDAY NIGHT INTO MONDAY. SINCE THIS IS VERY LATE THIRD PERIOD...WILL GO AHEAD AND HAVE HIGH END SCA GUSTS IN FOR THIS TIME FRAME.

&&

.TIDES... WATER LEVELS ARE CURRENTLY A HALF FOOT ABOVE ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING (70% FULL). WATER LEVELS HAVE RECOVERED FROM A RECENT BLOWOUT.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES REMAIN AT CURRENT DEPARTURES OR GRADUALLY RETURN TO ASTRONOMIC PREDICTIONS THROUGH TONIGHT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE... SMALL CRAFT ADVISORY FROM 9 AM SUNDAY TO 6 AM EST MONDAY FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/TIDES...ROGOWSKI LONG TERM...LISTEMAA MARINE...ROGOWSKI/LISTEMAA

.SHORT TERM /TONIGHT THROUGH SATURDAY/... WATER VAPOR LOOP SHOWS A TROUGH MOVING INTO THE ATLANTIC. THE NEXT NORTHERN STREAM WAVE IS DIVING SOUTHEAST INTO THE LAKE WINNIPEG REGION OF SOUTH CENTRAL CANADA...WHILE AN UPPER LOW BEGINS TO LIFT NORTHEAST INTO THE FOUR CORNERS REGION OF THE SOUTHWEST CONUS. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-140KT NORTHWESTERLY JET DIVES SOUTHEAST FROM THE CENTRAL GREAT LAKES THROUGH THE MID ATLANTIC. 12Z SURFACE ANALYSIS PLACED A WARM FRONTAL BOUNDARY FROM A 1000MB CYCLONE NORTH OF MINNESOTA SOUTHEAST ACROSS THE GREAT LAKES WHERE IT BECAME STATIONARY...AND FURTHER EAST THROUGH LOWER NEW ENGLAND WHERE IT REMAINED A COLD FRONT. A TROUGH WAS LOCATED IN THE LEE OF THE APPALACHIANS...WITH A 1026MB ANTICYCLONE ACROSS THE GULF STATES.

ACARS OBSERVATIONS DURING THE DAY INDICATE THE NORTHWESTERLY UPPER LEVEL JET CONTINUES TO LIFT NORTHEAST INTO NEW ENGLAND AS RIDGING OCCURS ALOFT. THIS WILL SUPPORT WARM ADVECTION MID LEVEL CLOUDS TO ADVECT IN ON THE JET AXIS THROUGH THE EVENING. LINEAR EXTRAPOLATION AND MODEL GUIDANCE SUGGEST THESE CLOUDS WILL LIFT NORTHEAST OF THE FORECAST AREA WITH THE JET AXIS BY MIDNIGHT. WITH DRY DEW POINTS...CLEARING SKIES AND DECOUPLING...HAVE UNDERCUT MOS GUIDANCE FOR LOW TEMPERATURES...ESPECIALLY ACROSS CENTRAL VIRGINIA WHERE CLEARING OCCURS FIRST. WARM ADVECTION ALOFT SHOULD SUPPORT MID 20S ACROSS THE HIGHER TERRAIN ABOVE 2500FT (WHERE TEMPERATURES WILL BE STEADY OR SLOWLY WARM).

CURRENTLY PLENTY OF CLEAR SKIES TO THE SOUTH AND WEST...AND AM EXPECTING A SUNNY START TO SATURDAY. AS THE UPPER LOW CONTINUES TO WEAKEN AND THEN LIFT THROUGH THE PLAINS TOMORROW...ANTICIPATE CLOUDINESS BEING ADVECTED DOWNSTREAM. IN ADDITION...FORCING WILL BE INCREASING ACROSS THE OHIO VALLEY DURING THE AFTERNOON IN ADVANCE OF THE NORTHERN STREAM SYSTEM TRAVERSING THE GREAT LAKES. WITH CONTINUED WARM ADVECTION...TEMPERATURES WILL REBOUND INTO THE 40S AND 50S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... FAIRLY ACTIVE MID LEVELS AT THE BEGINNING OF THE EXTENDED PERIOD. SEVERAL SHORTWAVES MOVING EAST IN THE FLOW. 1) A SOUTHERN STREAM SHORTWAVE PROGGED TO MOVE JUST SOUTH OF THE CWFA. 2) A SHORTWAVE OVER THE SOUTHERN GREAT LAKES THAT IS EXPECTED TO SHEAR OUT AS IS MOVES NORTHEAST. 3) LASTLY...A STRONG SHORTWAVE THAT WILL DIG A TROUGH OVER THE MID MISSISSIPPI VALLEY THAT IS EXPECTED TO CROSS THE CWFA SUNDAY NIGHT. EVEN AFTER SUNDAY NIGHT...THE FAST ZONAL FLOW WILL BRING SEVERAL HARD TO TIME SHORTWAVES EAST IN THE FLOW THROUGH TUESDAY. BY WEDNESDAY A SECOND LONGWAVE TROUGH WILL BEGIN TO MOVE OVER THE CWFA...FOLLOWED BY A THIRD TOWARDS THE END OF THE WEEK.

BY 00Z SUNDAY...A FRONTAL BOUNDARY IS MOVING EAST ACROSS THE CWFA. THIS FEATURE SHOULD BE EAST OF THE ARE BY EARLY SUNDAY. THE GFS PAINTS QPF ACROSS MOST OF THE CWFA...AND WILL BE COLD ENOUGH FOR ALL SNOW. HAVE RAISED THE POPS AROUND 10 PERCENT ACROSS THE BOARD. UPSLOPE SNOW SHOWERS ARE ONCE AGAIN EXPECTED ACROSS THE WESTERN RIDGES THROUGH MOST OF SUNDAY...AND WILL BE AIDED BY THE STRONG SHORTWAVE ENERGY. AS SECOND BOUNDARY IS EXPECTED MID-WEEK WITH MOST OF THE PRECIP CONFINED TO THE WESTERN HALF OF THE CWFA. GFS HAS A COASTAL LOW MOVING UP THE EASTERN SEABOARD LATE-WEEK.

&&

.AVIATION... RIDGING ALOFT WILL SHUNT MID LEVEL CLOUDS TO THE NORTHEAST AS WINDS DECOUPLE OVERNIGHT.

&&

.MARINE... THE SMALL CRAFT ADVISORY CONTINUES ACROSS THE MARYLAND CHESAPEAKE BAY. WITH GRADIENT RELAXING FROM THE WEST...WINDS ACROSS THE POTOMAC HAVE LOST THEIR GUSTINESS. THIS TREND WILL CONTINUE ACROSS THE BAY DURING THE LATE AFTERNOON.

12Z ETA/MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS DIMINISH DURING THE EVENING...BEFORE INCREASING TO ABOUT 10KT WITH A SOUTHERLY WIND COMPONENT. 12Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS ADDITIONAL MOMENTUM TRANSFER OF UP TO 20KTS SATURDAY FROM MID MORNING ONWARD.

SMALL CRAFT CONDITIONS ARE LIKELY ON THE WATERS SUNDAY NIGHT AND MONDAY BEHIND A FROPA.

&& WATER LEVELS ARE CURRENTLY A FOOT BELOW ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING (60% FULL). BLOWOUT CONDITIONS OCCURRED LAST NIGHT.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES RECOVER TO OR SLIGHTLY ABOVE ASTRONOMIC PERDITIONS THIS EVENING AND TONIGHT.

&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ530>534.

SMALL CRAFT ADVISORY FROM 10 AM TO 5 PM EST SATURDAY FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI LONG TERM/MARINE...LISTEMAA

.SHORT TERM... WATER VAPOR LOOP SHOWS A TROUGH MOVING INTO THE ATLANTIC. THE NEXT NORTHERN STREAM WAVE IS DIVING SOUTHEAST INTO THE LAKE WINNIPEG REGION OF SOUTH CENTRAL CANADA...WHILE AN UPPER LOW BEGINS TO LIFT NORTHEAST INTO THE FOUR CORNERS REGION OF THE SOUTHWEST CONUS. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-140KT NORTHWESTERLY JET DIVES SOUTHEAST FROM THE CENTRAL GREAT LAKES THROUGH THE MID ATLANTIC. 12Z SURFACE ANALYSIS PLACED A WARM FRONTAL BOUNDARY FROM A 1000MB CYCLONE NORTH OF MINNESOTA SOUTHEAST ACROSS THE GREAT LAKES WHERE IT BECAME STATIONARY...AND FURTHER EAST THROUGH LOWER NEW ENGLAND WHERE IT REMAINED A COLD FRONT. A TROUGH WAS LOCATED IN THE LEE OF THE APPALACHIANS...WITH A 1026MB ANTICYCLONE ACROSS THE GULF STATES.

RISING HEIGHTS WILL ENCOURAGE THE NORTHWESTERLY JET ALOFT TO PUSH INTO NEW ENGLAND. THIS WILL ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE REGION AND INITIATE WARM ADVECTION OFF THE SURFACE. THE RESULT WILL BE AN INCREASING MID LEVEL CLOUD DECK FROM NORTHWEST TO SOUTHEAST ALONG THE JET AXIS...PRODOMINTELY AFFECTING THE NORTHERN AND EASTERN FORECAST AREA THIS AFTERNOON AND EVENING.

MIXING A WARMING AIRMASS NEAR 900MB TO THE SURFACE SHOULD ALLOW SURFACE TEMPERATURES TO WARM THROUGH THE 20S...POSSIBLY NEARING FREEZING ACROSS THE SOUTHERN ZONES. WINDS GUSTING AT TIMES TO 20 MPH WILL KEEP WIND CHILLS NEAR 20F ACROSS MOST LOCATIONS THIS AFTERNOON.

&&

.AVIATION... WINDS GUSTS SLACKEN WITH THE DIMINISHING PRESSURE GRADIENT LATE THIS MORNING. EXPECT MID LEVEL MOISTURE ON NORTHWEST FLOW ALOFT TO ENTER THE REGION THIS AFTERNOON AS WARM ADVECTION BEGINS ALOFT.

&&

.MARINE... HAVE ALLOWED THE GALE WARNING TO EXPIRE...THE SMALL CRAFT ADVISORY CONTINUES.

00Z ETA/06Z MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS FALL FROM 17KT EARLY THIS MORNING TO ABOUT 10KT THIS EVENING. 06Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS ADDITIONAL MOMENTUM TRANSFER OF UP TO 25KTS THIS MORNING...AND 20KT THIS AFTERNOON.

&&

.TIDES... WATER LEVELS ARE CURRENTLY A FOOT BELOW ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING (57% FULL). BLOWOUT CONDITIONS OCCURRED LAST NIGHT.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES RECOVER TO OR SLIGHTLY ABOVE ASTRONOMIC PERDITIONS THIS EVENING AND TONIGHT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI

.UPDATE... RADAR INDICATED TRANSITION TO NE-SW ORIENTED MULTIPLE WIND PARALLEL BANDS OVER N CNTRL UPR MI IN THE WAKE OF THE SFC TROF THAT HAS SAGGED INTO SRN UPR MI. THIS HAS SHIFTED THE FOCUS OF THE HIGHER LES INTENSITY INTO THE HIGHER TERRAIN WEST AND S OF MARQUETTE AIDED BY MORE DIRECT UPSLOPE FLOW WHILE THE SNOW HAD DIMINISHED SUBSTANTIALLY IN MARQUETTE. 02Z KSAW TAMDAR SNDGS INDICATED A VERY FAVORABLE LES SNDG...NEARLY MOIST PROFILE TO 11K FT WITH TEMP OF -19C AT THE TOP OF A 6K FT INVERSION. MDLS HAVE BEEN CONSISTENT WITH DEPARTING DEEP MOISTURE AS THE ERN MN WRN WI SHRTWV SLIDES TO THE SE. SO...SNOWFALL RATES SHOULD TAPER OFF OVERNIGHT BUT COULD STILL BE ENOUGH FOR AN ADDITIONAL 2-4 INCHES IN FAVORED LOCATIONS IN THE HIGHER TERRAIN FROM WRN ALGER INTO W MARQUETTE COUNTY.

OVER THE WEST...THE SNOW HAS ALSO DIMINISHED SINCE EARLIER THIS EVENING. HOWEVER...WITH STORM TOTAL REPORT OF 6 INCHES AT IRONWOOD AND 3-6 INCHES IN THE KEWEENAW...GOING WARNING AND ADVISORY HEADLINES WILL REMAIN IN PLACE. SINCE THE DEEP MOISTURE EXITS A BIT EARLIER OVER THE KEWEENAW...ADDITIONAL OVERNIGHT SNOWFALL AMOUNTS SHOULD MAINLY BE IN THE 1-3 INCH RANGE WHILE 2-4 INCH AMOUNTS ARE EXPECTED NEAR IRONWOOD.

&&

.PREV DISCUSSION...ISSUED 355 PM EST SAT JAN 27 2007 .SYNOPSIS...

LATEST WATER VAPOR IMGRY ALONG WITH 400MB RUC HEIGHT ANALYSIS SHOWS A LOW PRESSURE TROUGH EXTENDING FROM JAMES BAY ACROSS THE UPPER GREAT LAKES AND INTO THE CENTRAL PLAINS. AT THE SFC THIS FEATURE IS REFLECTED AS A LOW PRESSURE TROUGH SITUATED OVER THE GREAT LAKES. ELSEWHERE ACROSS THE CONUS...UPPER LEVEL RIDGING IS NOTED IN THE NW UNITED STATES...FURTHER SOUTH...AN UPPER LEVEL LOW SITS JUST OFF THE COAST OF CALIFORNIA AND ZONAL FLOW DOMINATES THE EASTERN CONUS. BEHIND THE GREAT LAKES TROUGH...TEMPERATURES ARE COLD. AFTN TEMPERATURES ACROSS THE NORTHERN PLAINS ARE HOVERING JUST ABOVE ZERO WITH BELOW ZERO READINGS AT A FEW SPOTS...-3 AT GFK...6 AT 8D3...0 AT FAR. THESE TEMPS ALONG WITH MODEST NWRLY SFC WINDS HAS YIELDED WIND CHILL ADVISORIES FOR MUCH OF THIS AREA. CLOSER TO HOME TEMPS ARE MUCH WARMER WITH READINGS GETTING TO NEAR NORMAL TODAY OR SLIGHTLY ABOVE...25 AT ERY...19 AT NWS MQT...21 AT P59 AND 27 AT ISQ. LATEST RADAR TRENDS/SURFACE OBS SHOW LAKE EFFECT GOING STRONG ACROSS THE LAKE SUPERIOR/LAKE MICHIGAN NORTHERLY WIND SNOW BELTS. 12Z NAM BUFKIT SHOWS INVERSION HEIGHTS ON THE RISE...7000FT AT MQT...8000FT AT CMX THIS ALONG WITH 850MB TEMPS ARE AROUND -16 TO -20 GOOD LAKE EFFECT CONDITIONS. RADAR TRENDS SHOW THAT SNOW BANDS HAVE BEEN MAINLY MULTI-PARALLEL OFF OF THE WESTERN LAKE WITH SOUTHWARD PROPIGATING DOMINATE BANDING OCCURRING ACROSS THE EASTERN LAKE. CYCLONIC FLOW OVER THE EASTERN LAKE ASSOCIATED WITH THE DEPARTING TROUGH HAVE ALLOWED DOMINATE LES BANDS TO PROPAGATE SOUTHWESTLY AT ABOUT 10 KNOTS.

.SHORT TERM (TONIGHT AND SUNDAY)...

THE MAIN FORECAST CONCERN FOR THIS TIME PERIOD CONTINUES TO BE THE LAKE EFFECT SNOW THROUGH SUNDAY.

WILL NOT ADJUST THE END TIMES OF THE WARNINGS OR ADVISORIES AT THIS TIME...SIDING TO WAIT UNTIL LATER THIS EVENING OR TOMORROW TO MAKE THIS DECISION. THERE SEEMS TO CONTINUE TO BE EVIDENCE TO DO SO...AS WINDS BECOME MORE WESTERLY (310 TO 270) AFTER 18Z SUNDAY ACROSS THE WESTERN THIRD OF LAKE SUPERIOR. INVERSION HEIGHTS SHOULD ALSO BEGINS TO SLOWLY CRASH TO 5KFT BY 12Z SUNDAY...AND THEN CLOSER TO 2.5KFT BY 21Z...PUTTING AN END TO HEAVY SNOW. THE CENTRAL AND EASTERN GROUP OF WARNINGS AND ADVISORIES STILL MAY WORK TIME WISE...AS THE FOCUS JUST CONTINUES TO SHIFT SLOWLY EASTWARD...WITH SLIGHTLY MORE MOISTURE TO WORK WITH AND A LONGER FETCH ACROSS LAKE SUPERIOR. THIS WOULD CUT OFF BARAGA COUNTY FROM RECEIVING MUCH MORE SNOW...BUT ALGER AND NORTHERN SCHOOLCRAFT SHOULD STILL BE RECEIVING SOME ADDITIONAL SNOW ACCUMULATIONS THROUGH SUNDAY AFTERNOON. WILL ALSO NEED TO KEEP AN EYE ON HOW STRONG AND HOW FAST THE QUICK MOVING SURFACE HIGH PRESSURE SYSTEM...SLIDES SOUTH-SOUTHEASTWARD FROM NORTH DAKOTA LATE TODAY AND INTO THE SOUTHERN PLAINS SUNDAY AFTERNOON...DRYING OUT OUR AIRMASS.

OVERALL...WINDS HAVE BEEN SLOWER TO BECOME NORTHERLY THIS AFTERNOON...BUT ARE NOW STARTING TO COME AROUND...LEADING TO CONVERGENT SNOW BANDS ACROSS EASTERN MARQUETTE INTO ALGER COUNTY LATE THIS AFTERNOON. IN GENERAL...STUCK FAIRLY CLOSE TO THE RUC13 FOR WINDS...WHICH WAS FAIRLY CLOSE TO THE LOCAL WRF AND NAM. FOR COMPARISON THE GFS WAS TOO QUICK TO BRING DOWN THE NORTHERLY WINDS...SO HAVE RELIED HEAVILY ON NON-GFS MODELS FOR THIS FORECAST ISSUANCE FOR TONIGHT AND SUNDAY.

HESITATE TO RAISE FORECAST TEMPS MUCH OVERNIGHT...EVEN WITH OUR CURRENT FORECAST BRING A COUPLE OF DEGREES BELOW GUIDANCE VALUES. GIVEN PLENTY OF COLD AIR UPSTREAM...WITH SINGLE DIGIT READINGS BELOW AND ABOVE ZERO ACROSS MUCH OF NORTHERN MINNESOTA...WE SHOULD BE ABLE TO MAKE IT INTO THE SINGLE DIGITS ABOVE ZERO.

.LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...

.SUNDAY NIGHT...LES SHOULD BE GREATLY DIMINISHED AS RDGG/SUBSIDENCE BUILDS IN FROM THE W AND FLOW BECOMES INCREASING ANTICYCLONIC. DEVELOPING LAND BREEZES COULD HELP LOW-LVL CONVERGENCE AND FOCUS SOME BETTER LES BANDS OVER ALGER-LUCE-NRN SCHOOLCRAFT COUNTIES WHERE I HAVE MAINTAINED LIKELY POPS. ELSEWHERE ALONG LAKE SUPERIOR RDGG AND DRY AIR SHOULD DIMINISH LES TO LIGHT SNOW SHOWERS OR FLURRIES. CLEARING OVER THE WESTERN INTERIOR WILL ALLOW TEMPS TO PLUMMET TO AROUND -10F OVER SOME FAVORED COLD DRAINAGE LOCATIONS.

MONDAY AND MONDAY NIGHT...MODELS HAVE ANOTHER WEAK SHORTWAVE MOVING THROUGH BY AFTERNOON WHICH WILL SHIFT WEAK WIND FLOW BACK TO N AND BRING SOME LIGHT LES ONSHORE AGAIN SO KEPT CHC POPS OF 30/40 ALONG LAKE SUPERIOR ZONES.

TUE INTO WED...MODELS INDICATE FLOW WILL BACK MORE WNW IN ADVANCE OF NEXT CLIPPER SYSTEM AS 850 MB TEMPS REMAIN IN -16 TO -18C RANGE OVER LAKE SUPERIOR. THIS WNW FLOW WILL TEND TO SHIFT LES BANDS BACK ALONG THE LAKE SUPERIOR SHORELINE SO HAVE CONFINED CHC POPS FOR SNOW OVER THESE LOCATIONS WITH SLIGHT CHC POPS OR DRY CONDITIONS FARTHER INLAND.

FOLLOWED MORE CONSISTENT ECMWF WHICH SHOWS NEXT SIGNIFICANT CLIPPER SYSTEM TO MOVE IN ON THU SO INCLUDED CHC POPS FOR ENTIRE CWA AT THIS TIME. ECMWF INDICATES VERY COLD ARCTIC AIR (850 MB TEMPS OF AROUND -25C) WILL FOLLOW IN THE WAKE OF THIS CLIPPER SYSTEM. FORECAST BECOMES A BIT MORE UNCERTAIN BY NEXT FRI INTO SAT AS MODELS VARY ON TIMING OF CLIPPERS. THE GFS SHOWS ONE CLIPPER SYSTEM MOVING THROUGH ON FRI WITH ANOTHER TO FOLLOW ON SAT BRINGING REINFORCING SHOTS OF BITTER COLD ARCTIC AIR. THE 12Z ECMWF SHOWS A POLAR VORTEX DESCENDING FM HUDSON BAY WITH ANOTHER CLIPPER MOVING THROUGH THE AREA ON SAT WITH -30C AIR IN ITS WAKE. ECMWF SOLN SEEMS TO AGREE BETTER WITH GFS ENSEMBLE MEAN SO WOULD TEND TO FAVOR ECMWF SOLN MORE THAN OPERATIONAL GFS AT THIS POINT. ANYWAY...DESPITE TIMING DIFFERENCES...MODELS ARE IN AGREEMENT THAT NEXT WEEKEND WILL LIKELY BE BITTERLY COLD.

&&

.MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST SUN MIZ002-009. LAKE EFFECT SNOW WARNING 1 PM TODAY TO 1 AM EST MON MIZ004>006. LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST SUN MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUN MIZ084. LAKE EFFECT SNOW ADVISORY 1 PM TODAY UNTIL 1 AM EST MON MIZ013-085. HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR.

&&

$$

.UPDATE...JLB .SYNOPSIS...DJP .SHORT TERM...KF .LONG TERM...JV

.UPDATE...01Z MESOANALYSIS SHOWS WHAT IS ESSENTIALLY A BACK DOOR COLD FRONT EXTENDING ACROSS NORTHERN LAKE HURON AND THE STRAITS (BOUNDARY THROUGH MCD/SLH/PZQ)...BACK NORTHWEST INTO SOUTHERN LAKE SUPERIOR. WATER VAPOR IMAGERY SHOWING SEVERAL VORTICITY CENTERS IN THE VICINITY...ONE EAST OF LAKE SUPERIOR THAT ENHANCED EARLIER SNOWFALL ACROSS EASTERN UPPER...ANOTHER MOVING ACROSS THE THUMB AND WHICH BROUGHT LAKE ENHANCED SNOWFALL TO NORTHERN LOWER DURING THE DAY...AND ANOTHER WAVE OVER EASTERN MN DROPPING SOUTHEASTWARD. NO APX SOUNDING THIS EVENING DUE TO EQUIPMENT ISSUES...AIRCRAFT SOUNDING OUT OF PLN RIGHT AROUND 00Z PLACED INVERSION AROUND 750MB...850MB TEMPERATURES AT -12C...AND A MOIST LAYER EXTENDING JUST ABOVE 600MB. KAPX VWP SHOWING NORTHWEST WINDS (320-330) THROUGH 6K FEET AGL...KMQT VWP INDICATING NORTH WINDS OFF LAKE SUPERIOR AND LES BANDS ARE SHOWING A DECIDED SHIFT TOWARD THE NORTHEAST. THIS IS PULLING CONVECTION AWAY FROM WHITEFISH BAY... WITH JUST SOME RESIDUAL LIGHT SNOW/FLURRIES ALONG BAROCLINIC ZONE ASSOCIATED WITH BACKDOOR FRONT. WINDS ACROSS EASTERN UPPER ARE EXPECTED TO REMAIN TOO EASTERLY TO SUPPORT LES...ESPECIALLY WITH CONTRIBUTION FROM LAND BREEZE CIRCULATION. DOWNSLOPE FLOW AND DRY AIR ADVECTION MAY ALLOW FOR SOME CLEARING ACROSS EASTERN UPPER LATE. ACROSS NORTHWEST LOWER...TWO MAIN BANDS OF HIGHER REFLECTIVITY ACROSS NEWLY EXPANDED WARNING AREA FROM KALKASKA UP TO CHARLEVOIX...WITH A NARROW BAND OF HEAVIER SNOWFALL FROM NEAR CVX-GLR. SOME HEAVIER SNOWFALL OCCURRING BETWEEN FKS-CAD...ALL WITHIN NORTHWEST FLOW. WINDS WILL REMAIN FROM THE NORTHWEST THROUGH MIDNIGHT BEFORE SHIFTING TO THE NORTH BEHIND BACKDOOR FRONT...CONVERGENCE ALONG THIS FEATURE SHOULD ALSO PROVIDE FOR SOME ENHANCEMENT TO CONVECTION OVER NORTHERN LAKE MICHIGAN. AT THIS POINT DON`T SEE A NEED TO MAKE ANY OTHER HEADLINE ADJUSTMENTS TO WHAT HAS ALREADY BEEN DONE THIS EVENING. COULD SEE ANOTHER 2-4 INCHES ALONG US-131 NORTH OF MANTON DEPENDING ON HOW LONG IT TAKES WINDS TO SHIFT AND PUSH HEAVIER SNOWFALL TO THE SOUTH. MEANWHILE...SKIES HAVE CLEARED ACROSS SOUTHEAST PORTIONS OF THE FORECAST AREA IN WAKE OF SHORT WAVE TROUGH PASSAGE AND LIKELY HELPED BY DOWNSLOPING NORTHWEST FLOW. THIS IS PROBABLY SHORT LIVED...WOULD EXPECT CLOUD COVER AND SOME ADDITIONAL LIGHT SNOW/ FLURRIES TO ACCOMPANY BACKDOOR FRONT AS IT DROPS TOWARD THE M-55 CORRIDOR LATE TONIGHT.

JPB

&&

.PREV DISCUSSION... /ISSUED 816 PM EST SAT JAN 27 2007/

UNFORTUNATELY HAVE TO KEEP STAIR-STEPPING THE FORECAST UPWARD AS ADDITIONAL REPORTS OF 6 INCH/12 HOUR SNOWFALL AMOUNTS COMING IN FROM KALKASKA AND CHARLEVOIX COUNTIES. SO WILL THROW THEM INTO THE EARLIER ANTRIM COUNTY WARNING. IN ADDITION...TRIMMED BACK THE EFFECTIVE TIME OF THE REMAINING ADVISORY FOR OTSEGO/CRAWFORD TO END IT AT 10Z (5 AM)...SAME AS THE WARNING FOR THE US-131 COUNTIES.

JPB

/ISSUED 654 PM EST SAT JAN 27 2007/

LOOKS LIKE WILL NEED TO ADD ANTRIM COUNTY TO CURRENT WARNING WITH REPORTS OF 6 INCHES AROUND BELLAIRE. APPEARS INITIAL PUSH OF SYNOPTIC FORCING IS WANING...BUT NORTHWEST FLOW OFF LAKE MICHIGAN WILL PERSIST THROUGH AT LEAST MIDNIGHT...WHICH WILL KEEP THE THREAT FOR ADDITIONAL SNOW ACCUMULATIONS GOING. WINDS WILL SWITCH AFTER MIDNIGHT TO THE NORTH- NORTHEAST BEHIND SURFACE TROUGH CURRENTLY LYING ACROSS EASTERN UPPER...ANOTHER BURST OF SNOW ANTICIPATED ALONG THIS CONVERGENCE AXIS AFTER MIDNIGHT BUT ANTICIPATE ACCUMULATION POTENTIAL ACROSS ANTRIM COUNTY TO END ONCE WINDS SHIFT LATER TONIGHT. SO WARNING FOR ANTRIM COUNTY WILL ONLY RUN THROUGH THE OVERNIGHT HOURS (WILL HAVE IT EXPIRE AT 10Z TO COINCIDE WITH EARLY MORNING FORECAST ISSUES). NO OTHER CHANGES AT THIS TIME.

JPB

/ISSUED 417 PM EST SAT JAN 27 2007/

DISCUSSION...MID LEVEL SHORTWAVES...COMBINED WITH LAKE ENHANCED SURFACE TROUGH...CREATING A VERY CHALLENGING FORECAST FOR THE NEAR TERM. MID AFTERNOON SURFACE/SATELLITE/RUC/AND REGIONAL RADAR ANALYSIS SHOWS SHOWS FIRST OF TWO SHORTWAVES TO INFLUENCE NORTHERN MICHIGAN WEATHER RACING SOUTHEAST ACROSS NORTHERN LAKE MICHIGAN WITH THE SECOND DROPPING INTO NORTHERN MINNESOTA. AT THE SURFACE...ELONGATED SURFACE TROUGH EXTENDS NORTHWEST FROM LOW PRESSURE OVER SOUTHERN GEORGIAN BAY TO SOUTH CENTRAL LAKE SUPERIOR. LAKE INDUCED MESOLOW LOCATED OVER CHIPPEWA COUNTY MOVING SLOWLY SOUTHEAST ALONG SURFACE TROUGH IN RESPONSE TO FIRST SHORTWAVE. OVER WATER INSTABILITY ON THE INCREASE ACROSS THE NORTHERN LAKES AS CAA CONTINUES TO DROP 850MB TEMPERATURES... WITH 20Z RUC40 ANALYSIS SHOWING TEMPERATURES OF -13C OVER NORTHERN LAKE MICHIGAN AND EASTERN LAKE SUPERIOR. WEST NORTHWEST FLOW LAKE ENHANCED SNOW SHOWERS...SOME VERY INTENSE WITH SNOWFALL RATES AT AN INCH PER HOUR (EVEN HAD THUNDERSNOW REPORTED WITH THE 20Z HOUGHTON LAKE OBSERVATION) CONTINUE TO CUT ACROSS MUCH OF NORTHERN LOWER MICHIGAN. FARTHER NORTH...KMQT AND MONTREAL RIVER RADARS SHOWING INTENSE BANDS OVER CENTRAL AND EASTERN LAKE SUPERIOR BECOMING INCREASINGLY INFLUENCED BY MESOLOW CIRCULATION WITH NORTHWEST TO SOUTHEAST ORIENTED BANDS ON BACKSIDE OF CIRCULATION INTERSECTING THE LAKE SUPERIOR SHORELINE WILL WEST OF CHIPPEWA COUNTY. FORECAST CONCERN TONIGHT AND SUNDAY CENTERS ON AMOUNT AND LOCATION OF LAKE EFFECT SNOWS.

TONIGHT...SHORTWAVE OVER NORTHERN LAKE MICHIGAN CLEARS THE FORECAST AREA BY EARLY THIS EVENING AS EASTERN UPPER MICHIGAN SURFACE TROUGH SAGS SOUTH...REACHING A POSITION FROM NEAR ALPENA TO THE TIP OF THE LEELANAU COUNTY BY 06Z. SIDING WITH THE SLOWER NAM-WRF AND LATEST RUC IN THIS REGARD WITH MUCH BETTER INITIALIZATION OF SURFACE FEATURES. FLOW OVER NORTHERN LOWER SLOWLY VEERS FROM WEST NORTHWEST EARLY THIS EVENING TO MORE NORTHWEST BY MIDNIGHT. THERMODYNAMICALLY SPEAKING...LAKE EFFECT PARAMETERS OVER NORTHERN LAKE MICHIGAN REMAIN IMPRESSIVE THIS EVENING WITH NAM-WRF AND BUFKIT ANALYSIS SHOWING 850MB-700MB >80 PERCENT...DELTA T/S INCREASING TO 17C...LAKE INDUCED CAPE OF 370J/KG AND A LAKE INDUCED EQUILIBRIUM LEVEL OF 8.5KFT. GOOD CYCLONIC LOW LEVEL FLOW ALSO REMAINS OVER NORTHERN LOWER MICHIGAN THIS EVENING WITH ADDITIONAL ENHANCED CONVERGENCE AS TROUGH APPROACHES. HOWEVER...SOME KEY NEGATIVES TO MENTION. BANDS WILL BE SOMEWHAT TRANSITORY AS WINDS SLOWLY VEER AND LARGE SCALE SUBSIDENCE SETS IN BEHIND DEPARTING SHORTWAVE. THUS...NOT EXPECTING THINGS TO GET TOO OUT OF HAND THIS EVENING OVER NORTHWEST MICHIGAN WITH A GENERAL 2 TO 5 INCHES OF ACCUMULATION EXPECTED OVER FAVORED AREAS...WITH MOST OF THAT FALLING LATE THIS AFTERNOON THROUGH EARLY EVENING. HAVE GONE AHEAD AND ISSUED A LAKE SNOW ADVISORY TARGETING WHAT IS TYPICALLY KNOW AS THE BIG FIVE COUNTIES IN NORTHWEST MICHIGAN. OVER THE EASTERN UPPER...WINDS QUICKLY COME AROUND TO NORTH AND EVENTUALLY NORTHEAST...PUTTING THEM OUT OF PLAY FOR ANY SIGNIFICANT LAKE EFFECT. THINGS GET MORE INTERESTING LATER TONIGHT AS WINDS VEER TO NORTHERLY AND INSTABILITY INCREASES OVER NORTHERN LAKE MICHIGAN. AREA ALSO GETS CLIPPED BY NORTHERN FRINGES OF LARGE SCALE SYNOPTIC SUPPORT AS MINNESOTA SHORTWAVE DIVES INTO NORTHERN ILLINOIS. LAKE SNOW PARAMETERS REMAIN IMPRESSIVE WITH LAKE INDUCED CAPE AT NEARLY 500J/KG...EQUILIBRIUM LEVELS TO 10KFT...UNIDIRECTIONAL FLOW THROUGH THE CBL...AND OMEGA CENTERED IN THE PRIMARY DENDRITIC GROWTH ZONE FOR SEVERAL HOURS AFTER 06Z. PRIMARY CONCERN IS WINDS AS THEY LOOK TO SWING AROUND TO SLIGHTLY NORTHEAST LATE TONIGHT. IF THIS OCCURS..SNOW BANDS MAY REMAIN OFFSHORE. ALSO...BEST SYNOPTIC SUPPORT DOES PASS WELL SOUTH...REDUCING ENHANCEMENT POTENTIAL. STILL...COULD SEE A COUPLE HOURS OF INCH PER HOUR RATES OVER LEELANAU...BENZIE... GRAND TRAVERSE COUNTIES. OVER LAND TRAJECTORY SHOULD LIMIT RATES SOMEWHAT FOR MANISTEE COUNTY. NOT FORGETTING THE NORTHEAST LOWER...AS WINDS COME AROUND NORTHEAST COULD SEE A COUPLE INCHES ALONG THE LAKE HURON SHORELINE.

SUNDAY...SYNOPTIC SUPPORT PASSES OFF TO THE EAST DURING THE MORNING WITH RAPID MID LEVEL DRYING OVERSPREADING NORTHERN MICHIGAN DURING THE AFTERNOON. HOWEVER...IMPRESSIVE NORTH FLOW LAKE EFFECT LOOKS TO CONTINUE FOR SEVERAL HOURS UNTIL THIS OCCURS WITH LAKE INDUCED CAPE INCREASING TO 550J/KG AND EQUILIBRIUM LEVELS INCREASING TO 11KFT. EXPECT SEVERAL MORE INCHES OVER AFOREMENTIONED AREAS CENTERED NEAR AND WEST OF GRAND TRAVERSE BAY. THUS...FEEL WARNINGS ARE WARRANTED FOR BENZIE...LEELANAU...AND GRAND TRAVERSE COUNTIES WITH 24 HOUR AMOUNTS EXPECTED TO APPROACH LOW END WARNING CRITERIA WITH ADVISORY CRITERIA BEING MET IN MANISTEE COUNTY. LATER IN THE DAY...WINDS BACK AROUND NORTHWEST AND FLOW GOES ANTICYCLONIC AS SURFACE RIDGE BEGINS TO BUILD IN. SNOW SHOWERS WILL ONCE AGAIN BEGIN TO SPREAD FARTHER INLAND...ALBEIT SIGNIFICANTLY WEAKER.

MSB

LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)...COLD WEATHER WILL PREVAIL THROUGH THE ENTIRE PERIOD...AS BLOCKING WEST RIDGE PATTERN UP THE WESTERN NORTH AMERICA COAST WILL KEEP LONG WAVE TROUGHING ACROSS THE EASTERN TWO-THIRDS OF THE COUNTRY. THIS WILL RESULT IN A SERIES OF SHORTWAVE TROUGHS THAT WILL MOVE THROUGH THE GREAT LAKES REGION...AND PERIODS/BOUTS OF LAKE EFFECT AND LAKE ENHANCED SNOW SHOWERS. TIMING OF THESE DIFFERENT SNOW EVENTS WILL BE DEFINED WITH MORE PRECISION AS EACH EVENT NEARS. THIS TYPE OF PATTERN COULD LEAD TO BETTER/GROWING SNOWPACK FOR NRN MICHIGAN.

SUNDAY NIGHT...MAIN SHORTWAVE TROUGH AND SFC LOW WILL BE SE OF THE REGION SUNDAY NIGHT...WHICH WILL HAVE DRUG SFC TROUGHING THROUGH THE AREA.. LEFT BEHIND WILL BE A DRIER NW 1000-850MB WIND REGIME...WHICH WILL CONTINUE TO BACK WEST AS SFC HIGH PRESSURE AND MORE ANTI- CYCLONIC FLOW MOVES IN. LAKE INDUCED TROUGHING IS SUGGESTED BY BOTH GFS/NAM TO REDEVELOP FROM EASTERN LAKE SUPERIOR TO NRN LAKE HURON FOR THE OVERNIGHT HOURS. THIS SEEMS REASONABLE SEEING THAT THE LAND/WATER TEMPERATURE CONTRAST WILL BE INCREASING...AS H8 TEMPS DROP TO -20C. NOT A WHOLE LOT OF SNOW EXPECTED. UNDER THIS SYNOPTIC PATTERN EVOLUTION...SNOWFLAKES WILL BE GETTING PROGRESSIVELY SMALLER WITH COOLING TEMPS ALOFT...PLUS THE LOW LEVEL MOISTURE PROFILES ARE UNIMPRESSIVE...AND WE WILL BE LOSING THE ADDITIONAL CRYSTAL GROWTH IN THE LOWER LEVELS DUE TO THE COLDER TEMPERATURES. THIS EXPECTED EVEN THOUGH INVERSION HEIGHTS WILL BE DECENT FOR A PORTION OF THE EVENING AT 5500 FEET. MAY BE A BIT TRICKY ACROSS CHIPPEWA IF THE LAKE INDUCED TROUGHING ENHANCES LOW LEVEL CONVERGENCE OVER ANY ONE AREA...BUT THESE DETAILS ARE BEST DISCERNED CLOSER TO THE EVENT. WILL GO WITH A 1-1.5 INCH FORECAST. WINDS WILL BE SHIFTING MORE SO IN NRN LOWER AND WIND SPEEDS WILL BE DECREASING FROM 10-15 KNOTS TO AROUND 10KTS LATE. BEST SNOWS COULD BE FROM THE IMMEDIATE HIGHER TERRAIN TO ALONG THE COASTS.

MONDAY AND MONDAY NIGHT...NEXT CLIPPER ARRIVES FROM THE NC PLAINS... BUT TRAVERSES TO OUR SW ACROSS NRN IL...SPREADING BEST ISENTROPIC/WAA SNOWS ACROSS SW LOWER MICHIGAN. REALLY TOUGH TO SAY HOW MUCH SYNOPTIC SNOWS WILL AFFECT OUR SRN MOST AREAS...BUT AT LEAST SOME LIGHT SNOWS SHOULD SPREAD INTO AREAS SOUTH OF GRAND TRAVERSE BAY. ALL OTHER AREAS SHOW A PROMINENT DRY LAYER BETWEEN 650-850MB. ALSO...LIGHT LAKE EFFECT SNOWS WILL LIKELY BE ONGOING IN NW FLOW REGIMES...BUT WINDS WILL BE LIGHT (AROUND 10KTS OR EVEN LESS)...SO INLAND PENETRATION MAY BE MINIMAL. ALL-IN-ALL...WILL KEEP 40% CHANCE OF SNOW SHOWERS WILL REMAIN THE BEST WAY TO GO...UNTIL THIS SYSTEMS DETAILS CAN COME TOGETHER. BEST CHANCES AREA SOUTH OF M-72 AND WEST OF I-75. WILL TENTATIVELY PUT IN AROUND AN INCH FOR MONDAY. LOTS OF UNCERTAINTY REVOLVES AROUND THE 1000-850MB WIND DIRECTION FOR MONDAY AFTERNOON AND NIGHT...WHERE PREVIOUS THOUGHTS WERE FOR A SHIFT TO WSW/SW. THIS NOT SO THE CASE WITH LATEST DEVELOPMENTS...BUT FEEL AS THOSE THESE DETAILS ARE LIKE MOST OTHERS AT THIS TIME PERIOD OUT...BEST LEFT FOR WHEN THE EVENT COMES CLOSER TO CURRENT TIME. WILL KEEP 40% CHANCES IN SAME AREAS ALL OF MONDAY NIGHT.

TUESDAY...A GENERAL WNW/WEST FLOW TO BE AROUND AS SHORTWAVE TROUGH AXIS AND PERIOD OF SYNOPTIC SNOW LOOKS TO ROLL THROUGH THE REGION. THIS FEATURE DOES NOT LOOK ALL THAT IMPRESSIVE...WITH THE TEMP PROFILES DO SUGGEST THAT SLIGHT WARMING AND H8 TEMPS RISING INTO THE -16C RANGE MAY POSSIBLY LEAD TO BETTER FLAKES. NO WAY TO DETERMINE THESE SORT OF DETAILS...AND CHANCE OF SNOW SHOWER WILL SUFFICE. THE WINDS WILL AGAIN BE HARD TO DETERMINE...BUT AT LEAST SOME BACKING SHOULD LEAD TO BETTER SNOWS FOR AREAS WEST OF I-75 AND SOUTH OF M-68.

TUESDAY NIGHT THROUGH FRIDAY...AS RIDGING BUILDS ACROSS THE WESTERN NORTH AMERICAN COAST...BETTER AND BETTER POSSIBILITIES RESIDE WITH SEEING COLDER TEMPERATURES...ALTHOUGH THE COLDEST AIR WILL BE ENTRENCHED ACROSS THE NC PLAINS. A SERIES OF SHORTWAVES (SAME PATTERN) WILL IMPACT THE AREA...POSSIBLY RESULTING IN MORE SW FLOW EVENTS AS UPPER LEVEL WINDS GO FROM NW TO SW BY LATE IN THE WORK WEEK. THIS WOULD IMPACT THE LAKE MICHIGAN SHORELINE...AS WELL AS FAR NRN LAKE HURON. MODELS SEEM RATHER AGREEABLE ON THIS EVOLUTION ATTM. RIGHT NOW...TIMING IS FOR A COLD FRONT TO ARRIVE TUESDAY...AND AGAIN FRIDAY NIGHT WITH ASSOCIATED SYNOPTIC SUPPORT FOR LAKE ENHANCED SNOW. TEMPS ARE COLD ENOUGH...TO WHERE SUFFICIENT WIND SPEEDS IN THE 10-15MPH RANGE WOULD RESULT IN LAKE EFFECT SNOWS TO CONTINUE IN PORTIONS OF THE SW TO NW FLOW REGIMES OF NRN MICHIGAN THROUGH THIS ENTIRE TIME. SMD

&&

.APX WATCHES/WARNINGS/ADVISORIES...LAKE EFFECT SNOW WARNING... TONIGHT...MIZ019-021-027. LAKE EFFECT SNOW WARNING...TONIGHT THROUGH SUNDAY...MIZ020-025-026. LAKE EFFECT SNOW ADVISORY...TONIGHT THROUGH SUNDAY...MIZ031. LAKE EFFECT SNOW ADVISORY...TONIGHT...MIZ022-028.

&&

$$

.UPDATE...

MID-LVL DRYING IN ADVANCE OF CLIPPER SHORTWAVE MOVING DOWN FROM MANITOBA HAS EXTENDED A BIT FARTHER E OVER THE FCST AREA AS NOTED ON 12Z NAM AND RUC SNDGS AND CONFIRMED BY LOCAL TAMDAR SNDGS. THUS...HAVE TRIMMED BACK POPS TO LOW CHC OVER MUCH OF THE ERN FCST AREA AND ALSO SPREAD POTENTIAL FOR FLURRIES/FZDZ MIX INTO THESE COUNTIES AS WELL. SNDG PROFILE SUGGEST POTENTIAL FOR POSSIBLE FZDZ GIVEN MID-LVL DRYING AND LOW-LVL MOISTURE BARELY REACHING TOWARD -10C ISOTHERM.

WRESTLED A BIT WITH IDEA OF TAKING SNOW ADVISORY DOWN FOR SRN SCHOOLCRAFT COUNTY GIVEN DEGREE OF MID-LVL DRYING AND MARGINALLY COLD TEMPS FOR DECENT LAKE ENHANCEMENT. HOWEVER...RUC AND NAM MODELS STILL INDICATE GOOD LOW-LVL CONVERGENCE FOCUSED OVER SRN SCHOOLCRAFT COUNTY THIS AFTERNOON SO IN THE END DECIDED TO KEEP THE ADVISORY HEADLINE GOING AND MENTIONED ADDITIONAL SNOW ACCUMS OF 1-3".

&&

.PREV DISCUSSION... THERE ARE TWO BIG FCST CONCERNS EARLY THIS MORNING. FIRST IS LAKE ENHANCEMENT POTENTIAL IN SRLY FLOW OFF LAKE MICHIGAN. SECOND CONCERN REVOLVES AROUND UPCOMING HEADLINE LAKE EFFECT EVENT SAT/SUN.

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP VORTEX DESCENDING OVER NEW ENGLAND. NW FLOW AROUND THE WRN SIDE OF THIS VORTEX IS DOMINATING THE GREAT LAKES REGION EARLY THIS MORNING. MEANWHILE... UPSTREAM A FAIRLY IMPRESSIVE LOOKING SHORTWAVE IS HEADING SE THRU SASKATCHEWAN. 00Z SOUNDING FROM CWEG IN ALBERTA SHOWED A RESPECTABLE 12HR 500MB HEIGHT FALL OF 140M WITH THIS SYSTEM. AHEAD OF THE SHORTWAVE...POOL OF VERY WARM AIR DUE MOSTLY TO DOWNSLOPING OFF THE ROCKIES HAS PUSHED OUT OVER THE NRN PLAINS. 00Z RAOBS SHOWED 850MB TEMPS ALL THE WAY UP TO 11C AT KBIS AND 14C AT KUNR. THIS WAA HAS LED TO A BAND OF MID CLOUDS ACROSS THE UPPER MIDWEST/WRN GREAT LAKES REGION...AND SATELLITE AND REGIONAL RADAR IMAGERY SHOW CONVECTIVE ELEMENTS IN THE CLOUD BAND. 00Z KINL SOUNDING DID SHOW DRY-ADIABATIC LAPSE RATE BTWN 650 AND 550MB. SO FAR...ONLY SPOTTY -SN/FLURRIES HAVE BEEN NOTED. LACK OF PCPN IS DUE TO DRY AIRMASS PER 00Z KINL/KGRB SOUNDINGS. DRY AIR IS NOT TOO SUBSTANTIAL THOUGH AND WOULD EXPECT PCPN COVERAGE TO GRADUALLY INCREASE WITH TIME.

MODELS ARE IN GOOD AGREEMENT TAKING SHORTWAVE OVER SASKATCHEWAN TO JUST NW OF LAKE SUPERIOR BY 00Z SAT. ON THIS TRACK...IMPRESSIVE DEEP LAYER FORCING INDICATED BY NAM/GFS 850/500MB QVECTOR CONVERGENCE WILL PASS JUST NE OF UPPER MI THIS EVENING. EVEN SO...NW-SE ORIENTED MODEST DEEP LAYER FORCING WILL CONTINUE ALL DAY ACROSS MOST OF THE FCST AREA. AS THE SHORTWAVE APPROACHES...BROAD/ELONGATED SFC LOW PRES CURRENTLY OVER MANITOBA WILL SLIDE ESE TO CNTRL UPPER MI/NW LAKE SUPERIOR. GIVEN FORCING AND LOCATION OF STRENGTHENING LOW-LEVEL CONVERGENCE ACROSS CNTRL UPPER MI ALONG SFC TROF/WARM FRONT EXTENDING SE FROM APPROACHING LOW PRES...EXPECT MORE PERSISTENT -SN TO TAKE SHAPE OVER ROUGHLY THE E HALF OF FCST AREA TODAY. STRONG ISENTROPIC ASCENT (290K SFC OR ROUGHLY 700-750MB) IS SET FOR THE MORNING HRS THOUGH...SO HEAVIER SNOW SHOULD OCCUR THIS MORNING. THIS BRINGS UP THE PROSPECT FOR LAKE ENHANCEMENT OVER THE SE FCST AREA AS 850MB TEMPS WILL STILL BE ON THE ORDER OF -9 TO -12C OVER NRN LAKE MICHIGAN THIS MORNING AT THE TIME OF BEST FORCING. AT FIRST GLANCE...THERE WOULD APPEAR TO BE SOME CONCERN THAT THE STRONG WAA WOULD CUT OFF LAKE ENHANCEMENT POTENTIAL (00Z KMPX SOUNDING SHOWED 850MB TEMP OF ONLY -2C). HOWEVER...COOLING THRU UPWARD MOTION IN INTIAL DRY AIRMASS AND EVAPORATIVE COOLING SHOULD TEND TO SLOW THE ACTUAL WARMING AS MODELS INDICATE. AT THE LOW-LEVELS SRLY FLOW BECOMES CONVERGENT INTO SCHOOLCRAFT COUNTY AS SFC TROF DEVELOPS TOWARD NRN LAKE MICHIGAN. HAVE THUS OPTED TO ISSUE A SNOW ADVY (2-4 INCHES) FOR SRN SCHOOLCRAFT COUNTY WHERE BEST FETCH ACROSS THE LAKE TAKES AIM. CONSIDERED DELTA COUNTY...BUT WITH SHARP CONVERGENCE TO SET UP JUST E OF THERE...EXPECT LIGHTER SNOW ACCUMULATIONS. NONETHELESS...WILL NEED TO KEEP AN EYE ON THE FAR ERN PART OF DELTA COUNTY IN CASE SRLY FLOW BACKS MORE THAN EXPECTED BEFORE BEST FORCING DEPARTS. WILL BUFFER THE ADVY AREA WITH ROUGHLY 1-3 INCHES OF SNOW FROM ERN DELTA INTO ALGER/LUCE. GIVEN THE CONVECTIVE LOOK TO CLOUDS UPSTREAM...WILL NEED TO WATCH FOR SOME BURSTS OF HEAVIER SNOW AS STEEP MIDLEVEL LAPSE RATES SPREAD OVER THE AREA THIS MORNING. AFTER SOME MORNING -SN/FLURRIES WEST...POTENTIAL FOR FZDZ DEVELOPS AS MIDLEVEL MOISTURE EXITS LEAVING MOIST LAYER EXTENDING TO NEAR THE -10C ISOTHERM. SW HALF OF FCST AREA APPEARS MOST AT THREAT FOR SPOTTY -FZDZ WITH WARMER MOIST LAYER TEMPS...AND WILL INCLUDE MENTION THERE.

SHORTWAVE TRACKS ACROSS LAKE SUPERIOR TONIGHT...KEEPING BEST FORCING TO THE NE OF HERE. IN FACT...MODELS ACTUALLY SHOW STRONG SUBSIDENCE OVER MUCH OF THE FCST AREA FOR A GOOD PORTION OF TONIGHT. SO...AFTER SOME EVENING -SN OVER THE FAR E...THERE MAY NOT BE MUCH IF ANY PCPN AGAIN UNTIL LATE. THIS BRING US TO THE UPCOMING LAKE EFFECT EVENT. BROAD SFC LOW PRES OVER CNTRL UPPER MI/NW LAKE SUPERIOR THIS EVENING WILL SHIFT TO LAKE HURON/ERN LAKE SUPERIOR BY 12Z SAT. ANOTHER SHORTWAVE DROPPING SE WILL THEN SEND SFC LOW/TROF S ACROSS UPPER MI SAT. THE EXACT DETAILS OF HOW THIS WILL PLAY OUT IS UNCERTAIN. GFS INDICATES SHARP SFC TROF REACHING THE KEWEENAW AROUND 12Z...THEN CLEARING NRN UPPER MI BY 18Z SAT. NAM IS ABOUT 6HRS SLOWER. RUC13 AND REGIONAL CANADIAN MODEL ARE NEARLY IDENTICAL IN SHOWING EVEN SHARPER SFC TROFFING AND HINT AT MESOLOW OVER CNTRL LAKE SUPERIOR AT 12Z N OF STANNARD ROCK. MESOLOW THEN DROPS TO NEAR MUNISING BY 18Z. SO...TIMING IS ESSENTIALLY BTWN THE GFS AND NAM. SINCE THE REGIONAL CANADIAN OFTEN DID A MUCH BETTER JOB HANDLING WIND FIELDS OVER THE LAKE IN PAST EVENTS THIS SEASON WHEN THERE WERE SHARP CONVERGENCE ZONES OVER LAKE SUPERIOR (SEVERAL IN EARLY DEC)...WILL FAVOR ITS SOLUTION WITH REGARD TO DETAILS OF WIND FIELDS. OF COURSE...PAST PERFORMANCE IS NO GUARANTEE OF FUTURE PERFORMANCE...BUT IT DOES HAVE STRONG SUPPORT FROM THE RUC13. THIS SOLUTION RESULTS IN NW FLOW INTO WRN UPPER MI OVERNIGHT AS CAA GETS UNDERWAY...BUT IT WILL PROBABLY BE AFTER 12Z BEFORE LAKE ENHANCEMENT BEGINS IN ASSOCIATION WITH NEXT APPROACHING SHORTWAVE. WILL BRING IN -SHSN OVER THE W AND N OVERNIGHT AS 850MB TEMPS DROP TO -14C OR SO BY 12Z.

AS MESOLOW/SFC TROF DROP S INTO NRN UPPER MI DURING THE LATE MORNING INTO AFTN...EXPECT WIND SHIFT TO BE ACCOMPANIED BY A BAND OF HVY SNOW AS FCST SOUNDINGS INDICATING DEEP MOISTURE TO 10KFT OR MORE AND NO INVERSION. SNOW COULD BE QUITE INTENSE OVER NCNTRL UPPER MI IF MESOLOW DOES FORM ON SFC TROF. IN THE WAKE OF WIND SHIFT... CONDITIONS LOOK FAVORABLE FOR MDT/HVY LAKE ENHANCED SNOW TRANSITIONING TO PURE LES FOR N WIND FAVORED SNOWBELTS SAT AFTN THRU SAT NIGHT BEFORE SHARP DRYING AND CRASHING OF INVERSION TO 4-5KFT OCCURS EARLY SUN. WILL LEAVE GOING WATCHES AS IS (GOGEBIC/ONTONAGON/MARQUETTE/ALGER) GIVEN UNCERTAINTY ON INITIAL WIND FIELDS AND ON START TIME OF HVY SNOW...BUT IT DOES LOOK LIKE WATCHES WILL BE ABLE TO TRANSITION TO WARNINGS BASED ON VERY FAVORABLE LOOK OF FCST SOUNDINGS. ONE CHANGE WILL BE TO ADD BARAGA COUNTY TO WATCH AS N WIND DURING LAKE ENHANCEMENT PERIOD WILL FAVOR THAT AREA FOR HVY SNOW AS WELL. HOUGHTON/KEWEENAW/LUCE WILL LIKELY NEED ADVYS FOR THIS EVENT. ADVY TYPE SNOW MAY ALSO SPREAD AS FAR S AS DELTA COUNTY SAT NIGHT UNDER NRLY FLOW.

&&

.MQT WATCHES/WARNINGS/ADVISORIES... SNOW ADVY TODAY MIZ014. LAKE EFFECT SNOW WATCH LATE TONIGHT THRU SUN MORNING MIZ002-009. LAKE EFFECT SNOW WATCH SAT MORNING THRU SUN MORNING MIZ004. LAKE EFFECT SNOW WATCH SAT MORNING THRU SUN AFTN MIZ005-006.

&&

$$

VOSS (UPDATE) ROLFSON (PREV DISCUSSION)

.SHORT TERM /REST OF TODAY/...

MINOR CHANGES TO FORECAST THIS MORNING. TEMPERATURES HAVE BEEN SLOW TO REBOUND FROM OUR "ARCTIC BLAST"...AND WITH INCREASED CLOUD COVERAGE ACROSS THE AREA...EXPECT THAT TEMPS WILL HAVE TROUBLE WARMING.

TREND FOR SNOWFALL AND CLOUD COVER UPSTREAM WARRANTS AN INCREASED DURATION OF LIGHT SNOW ACROSS THE WESTERN MOUNTIANS.

&&

.PREV DISCUSSION... /ISSUED 708 AM EST FRI JAN 26 2007/

AVIATION /12Z-12Z/... HURON CONNECTION INTO THE LAURELS HAS DISSIPATED AND LAKE EFFECT SNOW SHOWERS OFF OF LAKE ERIE ARE WEAKENING AND BCMG DISORGANIZED GIVEN INCREASING BLYR DIRECTIONAL SHEAR AND SFC RIDGING POKING NEWD INTO NW PA. MVFR/VFR STRATOCU WILL LINGER OVER THE WESTERN AND CENTRAL MTN SITES WITH AC INCREASING FROM THE WEST AHEAD OF A SFC WARM FRONT. WARM ADVECTION LIGHT SNOW WILL BREAK OUT ACROSS THE WESTERN TERMINALS LATE THIS MORNING AND SHOULD CONTINUE THROUGH MUCH OF THE DAY. MVFR/IFR CONDS EXPECTED HERE...WITH VFR CONDS PREVAILING ELSEWHERE.

PREV DISCUSSION... /ISSUED 355 AM EST FRI JAN 26 2007/

SHORT TERM /TODAY THROUGH TONIGHT/...

HIGHLY SHEARED AND RATHER LIGHT LLVL FLOW WILL CONTINUE TO BACK TO THE SOUTHWEST THIS MORNING WITH LAYERED...WARM ADVECTION CLOUDS IN THE FORM OF STRATO/ALTO CU SPREADING SE INTO THE REGION FROM THE UPPER MIDWEST.

WILL CANCEL THE LES WARNINGS/ADVISORIES FOR NWRN PENN AND THE SNOW/BLOWING SNOW ADVISORY ADVIS FOR THE LAUREL HIGHLANDS.

HOWEVER...SINCE THE LACK OF WIDESPREAD CLOUDS AND SHSN HAS LED TO TEMPS OF ZERO TO -10F ACROSS THE NW MTNS...AND NEAR ZERO ACROSS THE LAUREL HIGHLANDS...WILL MAINTAIN THE WIND CHILL ADVIS THROUGH THIS MORNING...AS IT ONLY REQUIRES A 5-10 MPH BREEZE TO KNOCK THE WIND CHILL TO -15 TO -20F IN THESE AREAS.

THICKENING CLOUDS THIS AFTERNOON/EVENING WILL PRECEDE A FEW PERIODS OF LIGHT SNOW...MAINLY ACROSS THE NW HALF OF OUR CWA. THERE COULD BE ANOTHER FEW INCHES OF TOTAL SNOW ACCUMULATION ACROSS THE NW LATER TODAY AND TONIGHT...WITH GENERALLY A COATING TO ONE INCH POSSIBLE ACROSS THE LAUREL HIGHLANDS AND THE CENTRAL MTNS...NEAR AND TO THE NORTH OF INTERSTATE 80.

TEMPS LATER TONIGHT IN THE CLOUD BEARING LAYER WILL WARM TO THE SINGLE DIGITS BELOW ZERO...AND OUT OF THE MAIN DENDRITIC CRYSTAL GROWTH REGION AS DRY AIR ALOFT PENETRATES DOWN TO 5-7 KFT AGL. THIS WILL ALSO MINIMIZE THE CHC FOR ICE CRYSTAL SEEDING FROM A MID CLOUD LAYER. CONCUR WITH SURROUNDING WFOS TO THE NORTH THAT FZDZ MAIN BE THE PRIMARY PRECIP FORM LATE TONIGHT...BEFORE COLDER AIR MOVES IN ON A VEERING BOUNDARY LAYER FLOW SATURDAY AFTERNOON CHANGING THE PRECIP BACK TO SCATTERED SHSN.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...

ANOTHER...RATHER STRONG UPPER SHORT WAVE DIVES SE ACROSS THE GREAT LAKES SATURDAY NIGHT/SUNDAY BRINGING AN INCREASING CHC FOR SNOW SHOWERS AND THE POTENTIAL FOR MDT SNOW ACCUM FROM LAKE EFFECT/OROGRAPHIC LIFT ACROSS THE NW MTNS AND LAUREL HIGHLANDS SUNDAY AFTERNOON AND NIGHT.

COLDER AIR...SIMILAR TO THAT OF YESTERDAY...WILL FOLLOW FOR MONDAY THROUGH WEDNESDAY WITH SCATTERED MAINLY MTN SNOW SHOWERS.

AVIATION /09Z-06Z/...

07Z SFC ANALYSIS PLACES ARCTIC FRONTAL BNDRY ACROSS SRN VA WITH +3MB PRES RISES ALONG THE MID-ATLANTIC SEABOARD. GIVEN THE WEAKENING GRADIENT OVER CENTRAL PA...SFC WNDS HAVE RELAXED TO 8-12KTS. LES BAND WITH HURON CONNECTION CONTINUES TO AFFECT THE LAUREL MTNS WITH KJST DOWN TO IFR /VIS/ FOR THE LAST FEW HOURS BUT APPERS TO BE BCMG DISORGANIZED WITH BACKING FETCH. ELSEWHERE...VFR CONDS PREVAILING WITH SKC-SCT040 COURTESY OF WEAK HIGH PRESSURE/SUBSIDENCE IN BETWEEN THE AFOREMENTIONED ARCTIC BNDRY AND AN UPSTREAM S/W DISTURBANCE CURRENTLY MOVG ACROSS LAKE WINNIPEG IN CENTRAL MANITOBA. A SFC REFLECTION ASSOC WITH THIS FEATURE WAS ANALYZED ALONG THE MN/CANADA BORDER WITH AN ATTENDANT WARM FRONT DRAPED FROM LAKE HURON ESEWD INTO THE CENTRAL LP OF MI. IR SAT IMAGERY SHOWING MID LVL CLOUDS ADVANCING SEWD ACROSS THE CENTRAL GREAT LAKES AND INTO ERN OH ACCOMPANYING THE WARM FRONT. XPECT THESE CLOUDS TO OVERSPREAD THE CENTRAL PA AIRFIELDS FROM MID/LATE MORNING IN THE WEST TO EARLY THIS AFT IN THE EAST. LOWERING INVERSION HEIGHTS /AOB 5KFT BY 12Z/ AND AN INCREASINGLY LESS FAVORABLE BLYR FETCH SHOULD DIMINISH ANY LINGERING LES ACTIVITY AS HIGH PRES NUDGES NEWD FM THE TN VLY. LOOK FOR MVFR CONDS TO HANG ON FOR A WHILE AT KBFD/KJST WITH VFR FLYING FURTHER EAST. MID LVL DECK WILL GRADUALLY LWR THU THE DAY WITH SOME AREAS OF LIGHT WAA/UPSLOPE SNOW PSBL. SFC WNDS ALREADY BACKING TO MORE WRLY ATTM...AND WILL COME AROUND TO THE WSW BY LATER TDY AS THE WARM FRONT LIFTS NEWD ACROSS THE COMMONWEALTH.

LATER IN THE PD ACROSS THE NW MTNS...FCAST SOUNDINGS INDICATE NO ICE INTRODUCTION ALOFT WITH SATURATION AOB 10KFT. WITH THERMAL PROFILES BLW FZG...FZDZ A POSSIBILITY WITH SUPERCOOLED WATER IN THE CLOUD LYR. THIS MAY ALSO LEAD TO LGT TO MOD RIME ICING FOR AIRCRAFT FLYING THROUGH THIS REGION.

&&

.CTP WATCHES/WARNINGS/ADVISORIES... NONE.

&&

$$

SHORT TERM...CONNELY/DANGELO

.AVIATION /12Z-12Z/... HURON CONNECTION INTO THE LAURELS HAS DISSIPATED AND LAKE EFFECT SNOW SHOWERS OFF OF LAKE ERIE ARE WEAKENING AND BCMG DISORGANIZED GIVEN INCREASING BLYR DIRECTIONAL SHEAR AND SFC RIDGING POKING NEWD INTO NW PA. MVFR/VFR STRATOCU WILL LINGER OVER THE WESTERN AND CENTRAL MTN SITES WITH AC INCREASING FROM THE WEST AHEAD OF A SFC WARM FRONT. WARM ADVECTION LIGHT SNOW WILL BREAK OUT ACROSS THE WESTERN TERMINALS LATE THIS MORNING AND SHOULD CONTINUE THROUGH MUCH OF THE DAY. MVFR/IFR CONDS EXPECTED HERE...WITH VFR CONDS PREVAILING ELSEWHERE.

&&

.PREV DISCUSSION... /ISSUED 355 AM EST FRI JAN 26 2007/

SHORT TERM /TODAY THROUGH TONIGHT/...

HIGHLY SHEARED AND RATHER LIGHT LLVL FLOW WILL CONTINUE TO BACK TO THE SOUTHWEST THIS MORNING WITH LAYERED...WARM ADVECTION CLOUDS IN THE FORM OF STRATO/ALTO CU SPREADING SE INTO THE REGION FROM THE UPPER MIDWEST.

WILL CANCEL THE LES WARNINGS/ADVISORIES FOR NWRN PENN AND THE SNOW/BLOWING SNOW ADVISORY ADVIS FOR THE LAUREL HIGHLANDS.

HOWEVER...SINCE THE LACK OF WIDESPREAD CLOUDS AND SHSN HAS LED TO TEMPS OF ZERO TO -10F ACROSS THE NW MTNS...AND NEAR ZERO ACROSS THE LAUREL HIGHLANDS...WILL MAINTAIN THE WIND CHILL ADVIS THROUGH THIS MORNING...AS IT ONLY REQUIRES A 5-10 MPH BREEZE TO KNOCK THE WIND CHILL TO -15 TO -20F IN THESE AREAS.

THICKENING CLOUDS THIS AFTERNOON/EVENING WILL PRECEDE A FEW PERIODS OF LIGHT SNOW...MAINLY ACROSS THE NW HALF OF OUR CWA. THERE COULD BE ANOTHER FEW INCHES OF TOTAL SNOW ACCUMULATION ACROSS THE NW LATER TODAY AND TONIGHT...WITH GENERALLY A COATING TO ONE INCH POSSIBLE ACROSS THE LAUREL HIGHLANDS AND THE CENTRAL MTNS...NEAR AND TO THE NORTH OF INTERSTATE 80.

TEMPS LATER TONIGHT IN THE CLOUD BEARING LAYER WILL WARM TO THE SINGLE DIGITS BELOW ZERO...AND OUT OF THE MAIN DENDRITIC CRYSTAL GROWTH REGION AS DRY AIR ALOFT PENETRATES DOWN TO 5-7 KFT AGL. THIS WILL ALSO MINIMIZE THE CHC FOR ICE CRYSTAL SEEDING FROM A MID CLOUD LAYER. CONCUR WITH SURROUNDING WFOS TO THE NORTH THAT FZDZ MAIN BE THE PRIMARY PRECIP FORM LATE TONIGHT...BEFORE COLDER AIR MOVES IN ON A VEERING BOUNDARY LAYER FLOW SATURDAY AFTERNOON CHANGING THE PRECIP BACK TO SCATTERED SHSN.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...

ANOTHER...RATHER STRONG UPPER SHORT WAVE DIVES SE ACROSS THE GREAT LAKES SATURDAY NIGHT/SUNDAY BRINGING AN INCREASING CHC FOR SNOW SHOWERS AND THE POTENTIAL FOR MDT SNOW ACCUM FROM LAKE EFFECT/OROGRAPHIC LIFT ACROSS THE NW MTNS AND LAUREL HIGHLANDS SUNDAY AFTERNOON AND NIGHT.

COLDER AIR...SIMILAR TO THAT OF YESTERDAY...WILL FOLLOW FOR MONDAY THROUGH WEDNESDAY WITH SCATTERED MAINLY MTN SNOW SHOWERS.

AVIATION /09Z-06Z/...

07Z SFC ANALYSIS PLACES ARCTIC FRONTAL BNDRY ACROSS SRN VA WITH +3MB PRES RISES ALONG THE MID-ATLANTIC SEABOARD. GIVEN THE WEAKENING GRADIENT OVER CENTRAL PA...SFC WNDS HAVE RELAXED TO 8-12KTS. LES BAND WITH HURON CONNECTION CONTINUES TO AFFECT THE LAUREL MTNS WITH KJST DOWN TO IFR /VIS/ FOR THE LAST FEW HOURS BUT APPERS TO BE BCMG DISORGANIZED WITH BACKING FETCH. ELSEWHERE...VFR CONDS PREVAILING WITH SKC-SCT040 COURTESY OF WEAK HIGH PRESSURE/SUBSIDENCE IN BETWEEN THE AFOREMENTIONED ARCTIC BNDRY AND AN UPSTREAM S/W DISTURBANCE CURRENTLY MOVG ACROSS LAKE WINNIPEG IN CENTRAL MANITOBA. A SFC REFLECTION ASSOC WITH THIS FEATURE WAS ANALYZED ALONG THE MN/CANADA BORDER WITH AN ATTENDANT WARM FRONT DRAPED FROM LAKE HURON ESEWD INTO THE CENTRAL LP OF MI. IR SAT IMAGERY SHOWING MID LVL CLOUDS ADVANCING SEWD ACROSS THE CENTRAL GREAT LAKES AND INTO ERN OH ACCOMPANYING THE WARM FRONT. XPECT THESE CLOUDS TO OVERSPREAD THE CENTRAL PA AIRFIELDS FROM MID/LATE MORNING IN THE WEST TO EARLY THIS AFT IN THE EAST. LOWERING INVERSION HEIGHTS /AOB 5KFT BY 12Z/ AND AN INCREASINGLY LESS FAVORABLE BLYR FETCH SHOULD DIMINISH ANY LINGERING LES ACTIVITY AS HIGH PRES NUDGES NEWD FM THE TN VLY. LOOK FOR MVFR CONDS TO HANG ON FOR A WHILE AT KBFD/KJST WITH VFR FLYING FURTHER EAST. MID LVL DECK WILL GRADUALLY LWR THU THE DAY WITH SOME AREAS OF LIGHT WAA/UPSLOPE SNOW PSBL. SFC WNDS ALREADY BACKING TO MORE WRLY ATTM...AND WILL COME AROUND TO THE WSW BY LATER TDY AS THE WARM FRONT LIFTS NEWD ACROSS THE COMMONWEALTH.

LATER IN THE PD ACROSS THE NW MTNS...FCAST SOUNDINGS INDICATE NO ICE INTRODUCTION ALOFT WITH SATURATION AOB 10KFT. WITH THERMAL PROFILES BLW FZG...FZDZ A POSSIBILITY WITH SUPERCOOLED WATER IN THE CLOUD LYR. THIS MAY ALSO LEAD TO LGT TO MOD RIME ICING FOR AIRCRAFT FLYING THROUGH THIS REGION.

&&

.CTP WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR PAZ004>006- 010>012-017-018-024-033-037-041-042.

&&

$$

AVIATION...STEINBUGL

.SHORT TERM /TODAY THROUGH TONIGHT/...

HIGHLY SHEARED AND RATHER LIGHT LLVL FLOW WILL CONTINUE TO BACK TO THE SOUTHWEST THIS MORNING WITH LAYERED...WARM ADVECTION CLOUDS IN THE FORM OF STRATO/ALTO CU SPREADING SE INTO THE REGION FROM THE UPPER MIDWEST.

WILL CANCEL THE LES WARNINGS/ADVISORIES FOR NWRN PENN AND THE SNOW/BLOWING SNOW ADVISORY ADVIS FOR THE LAUREL HIGHLANDS.

HOWEVER...SINCE THE LACK OF WIDESPREAD CLOUDS AND SHSN HAS LED TO TEMPS OF ZERO TO -10F ACROSS THE NW MTNS...AND NEAR ZERO ACROSS THE LAUREL HIGHLANDS...WILL MAINTAIN THE WIND CHILL ADVIS THROUGH THIS MORNING...AS IT ONLY REQUIRES A 5-10 MPH BREEZE TO KNOCK THE WIND CHILL TO -15 TO -20F IN THESE AREAS.

THICKENING CLOUDS THIS AFTERNOON/EVENING WILL PRECEDE A FEW PERIODS OF LIGHT SNOW...MAINLY ACROSS THE NW HALF OF OUR CWA. THERE COULD BE ANOTHER FEW INCHES OF TOTAL SNOW ACCUMULATION ACROSS THE NW LATER TODAY AND TONIGHT...WITH GENERALLY A COATING TO ONE INCH POSSIBLE ACROSS THE LAUREL HIGHLANDS AND THE CENTRAL MTNS...NEAR AND TO THE NORTH OF INTERSTATE 80.

TEMPS LATER TONIGHT IN THE CLOUD BEARING LAYER WILL WARM TO THE SINGLE DIGITS BELOW ZERO...AND OUT OF THE MAIN DENDRITIC CRYSTAL GROWTH REGION AS DRY AIR ALOFT PENETRATES DOWN TO 5-7 KFT AGL. THIS WILL ALSO MINIMIZE THE CHC FOR ICE CRYSTAL SEEDING FROM A MID CLOUD LAYER. CONCUR WITH SURROUNDING WFOS TO THE NORTH THAT FZDZ MAIN BE THE PRIMARY PRECIP FORM LATE TONIGHT...BEFORE COLDER AIR MOVES IN ON A VEERING BOUNDARY LAYER FLOW SATURDAY AFTERNOON CHANGING THE PRECIP BACK TO SCATTERED SHSN.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...

ANOTHER...RATHER STRONG UPPER SHORT WAVE DIVES SE ACROSS THE GREAT LAKES SATURDAY NIGHT/SUNDAY BRINGING AN INCREASING CHC FOR SNOW SHOWERS AND THE POTENTIAL FOR MDT SNOW ACCUM FROM LAKE EFFECT/OROGRAPHIC LIFT ACROSS THE NW MTNS AND LAUREL HIGHLANDS SUNDAY AFTERNOON AND NIGHT.

COLDER AIR...SIMILAR TO THAT OF YESTERDAY...WILL FOLLOW FOR MONDAY THROUGH WEDNESDAY WITH SCATTERED MAINLY MTN SNOW SHOWERS.

&&

.AVIATION /09Z-06Z/...

07Z SFC ANALYSIS PLACES ARCTIC FRONTAL BNDRY ACROSS SRN VA WITH +3MB PRES RISES ALONG THE MID-ATLANTIC SEABOARD. GIVEN THE WEAKENING GRADIENT OVER CENTRAL PA...SFC WNDS HAVE RELAXED TO 8-12KTS. LES BAND WITH HURON CONNECTION CONTINUES TO AFFECT THE LAUREL MTNS WITH KJST DOWN TO IFR /VIS/ FOR THE LAST FEW HOURS BUT APPERS TO BE BCMG DISORGANIZED WITH BACKING FETCH. ELSEWHERE...VFR CONDS PREVAILING WITH SKC-SCT040 COURTESY OF WEAK HIGH PRESSURE/SUBSIDENCE IN BETWEEN THE AFOREMENTIONED ARCTIC BNDRY AND AN UPSTREAM S/W DISTURBANCE CURRENTLY MOVG ACROSS LAKE WINNIPEG IN CENTRAL MANITOBA. A SFC REFLECTION ASSOC WITH THIS FEATURE WAS ANALYZED ALONG THE MN/CANADA BORDER WITH AN ATTENDANT WARM FRONT DRAPED FROM LAKE HURON ESEWD INTO THE CENTRAL LP OF MI. IR SAT IMAGERY SHOWING MID LVL CLOUDS ADVANCING SEWD ACROSS THE CENTRAL GREAT LAKES AND INTO ERN OH ACCOMPANYING THE WARM FRONT. XPECT THESE CLOUDS TO OVERSPREAD THE CENTRAL PA AIRFIELDS FROM MID/LATE MORNING IN THE WEST TO EARLY THIS AFT IN THE EAST. LOWERING INVERSION HEIGHTS /AOB 5KFT BY 12Z/ AND AN INCREASINGLY LESS FAVORABLE BLYR FETCH SHOULD DIMINISH ANY LINGERING LES ACTIVITY AS HIGH PRES NUDGES NEWD FM THE TN VLY. LOOK FOR MVFR CONDS TO HANG ON FOR A WHILE AT KBFD/KJST WITH VFR FLYING FURTHER EAST. MID LVL DECK WILL GRADUALLY LWR THU THE DAY WITH SOME AREAS OF LIGHT WAA/UPSLOPE SNOW PSBL. SFC WNDS ALREADY BACKING TO MORE WRLY ATTM...AND WILL COME AROUND TO THE WSW BY LATER TDY AS THE WARM FRONT LIFTS NEWD ACROSS THE COMMONWEALTH.

LATER IN THE PD ACROSS THE NW MTNS...FCAST SOUNDINGS INDICATE NO ICE INTRODUCTION ALOFT WITH SATURATION AOB 10KFT. WITH THERMAL PROFILES BLW FZG...FZDZ A POSSIBILITY WITH SUPERCOOLED WATER IN THE CLOUD LYR. THIS MAY ALSO LEAD TO LGT TO MOD RIME ICING FOR AIRCRAFT FLYING THROUGH THIS REGION.

&&

.CTP WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR PAZ004>006- 010>012-017-018-024-033-037-041-042.

&&

$$

SHORT TERM...LAMBERT LONG TERM...LAMBERT AVIATION...STEINBUGL

.SYNOPSIS...THE PACIFIC NORTHWEST WILL REMAIN UNDER A STRONG RIDGE OF HIGH PRESSURE FOR THE NEXT WEEK. THE RIDGE WILL PRODUCE DRY WEATHER...SUNSHINE...AND SLIGHTLY WARMER THAN NORMAL DAYTIME TEMPERATURES.

&&

.SHORT TERM...SATELLITE IMAGERY A COUPLE OF PATCHES OF STRATUS STILL LEFT OVER THE SOUTHWEST INTERIOR OTHERWISE SKIES ARE CLEAR ACROSS THE CWA THIS AFTERNOON. WITH THE OFFSHORE SURFACE GRADIENTS CASCADE FOOTHILLS ARE THE WARM SPOT THIS AFTERNOON WITH TEMPERATURES IN THE MID 50S. ACARS SOUNDINGS SHOW NOT MUCH LEFT OF THE INVERSION THAT WAS PRESENT EARLIER TODAY. LOW LEVEL INVERSION WILL REFORM DURING THE OVERNIGHT HOURS THROUGH TUESDAY MORNING BUT MODEL SOUNDINGS SHOW THE INVERSIONS BREAKING DURING THE AFTERNOON HOURS. THIS COMBINED WITH THE OFFSHORE FLOW WILL HELP WITH POSSIBLE AIR QUALITY ISSUES. PERSISTENCE LOOKS LIKE A GOOD FORECAST THROUGH THE SHORT TERM. LITTLE CHANGE IN THE UPPER LEVEL PATTERN WITH THE UPPER LEVEL RIDGE REMAINING OFFSHORE EXTENDING INTO BRITISH COLUMBIA WITH AN UPPER LEVEL LOW NEAR THE CENTRAL/SOUTHERN CALIFORNIA COAST. SURFACE HIGH PRESSURE WILL CONTINUE EAST OF THE CASCADES WITH THE RESULTING LOW LEVEL OFFSHORE FLOW CONTINUING THROUGH TUESDAY. WARM SPOTS WILL CONTINUE TO BE THE CASCADE FOOTHILLS AS WELL AS THE COAST. MOST LOCATIONS WILL BE A FEW DEGREES ABOVE NORMAL FOR HIGHS THROUGH THE SHORT TERM.

.LONG TERM...EXTENDED MODELS IN GOOD AGREEMENT FOR THE EARLY PORTION OF THE LONG TERM WITH THE BLOCKING UPPER LEVEL PATTERN REMAINING IN PLACE. GFS CARVES THE UPPER LEVEL TROUGH OVER THE MIDDLE PORTION OF THE COUNTY FURTHER WEST AND RETROGRADES THE UPPER LEVEL RIDGE BEGINNING FRIDAY WHICH WOULD OPEN THE DOOR TO SOME COLDER AIR REACHING THE AREA. BOTH THE CANADIAN AND EURO MODEL KEEP THE COLDER AMS TO THE EAST OF THE AREA THROUGH THE EXTENDED PERIOD. GIVEN THE STABLE UPPER LEVEL PATTERN AND THE TENDENCY OF THE GFS TO SPILL THE COLD AIR TOO FAR WEST WILL STAY WITH THE EURO AND CANADIAN SOLUTION FOR NOW AND JUST SHOW A SLIGHT DROP IN THE DAYTIME TEMPS WITH THE WEAKENING OF THE LOW LEVEL OFFSHORE FLOW. GFS ALSO BRINGS A FRONT THROUGH THE UPPER LEVEL RIDGE POSITION FOR NEXT WEEKEND. THIS FEATURE LOOKS TO BE OVERDONE AT THIS POINT. WILL KEEP THE FORECAST DRY IN THE LONG TERM. FELTON

&&

.AVIATION...DRY AND STABLE OFFSHORE FLOW WILL CONTINUE FOR NEXT 24 HOURS...THOUGH THE STRENGTH OF THE OFFSHORE FLOW WILL WEAKEN SOME. COULD GET SOME SHALLOW FOG BRIEFLY SLOP INTO SEA-TAC FROM THE KENT VALLEY AROUND SUNRISE ON SUNDAY. OTHERWISE CLEAR WITH LIGHT NORTHEAST FLOW.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...NONE.

$$

WEATHER.GOV/SEATTLE

.SHORT TERM...THROUGH SUNDAY NIGHT

FORECAST CONCERNS WERE PRIMARILY FOCUSED ON PRECIPITATION TYPE/CHANCE TODAY...THEN TEMPERATURES...WIND CHILLS AND SNOWFALL DURING THE WEEKEND.

EARLY MORNING SURFACE ANALYSIS HAD LOW PRESSURE NEAR LAKE WINNIPEG... WITH STRONG WARM AIR ADVECTION ACROSS THE UPPER MISSISSIPPI VALLEY. IN FACT...00Z 26JAN07 UPPER AIR SOUNDINGS INDICATED 850MB TEMPERATURES AS WARM AS 7C AT KABR AND 11C AT KBIS. 11-3.9 MICRON SATELLITE IMAGERY HAD LOW CLOUDS ADVANCING ACROSS THE FORECAST AREA...WITH FLURRIES REPORTED AT AWOS/ASOS SITES IN SOUTHERN MN AND NORTHERN IOWA. LAPS SOUNDINGS SUPPORTED SHALLOW CLOUD DECK...AS CORROBORATED BY 05Z TAMDAR FROM KMSP. WATER VAPOR IMAGERY SHOWED VIGOROUS WAVE TRANSITING SOUTHEASTWARD ACROSS MANITOBA.

00Z 26JAN07 MODELS WERE IN GOOD AGREEMENT ON WELL ADVERTISED TROUGH...WHICH IS EXPECTED TO CARVE OUT OVER THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY. EVEN POSITION AND STRENGTH OF VARIOUS SHORT WAVES ANTICIPATED TO CIRCULATE IN THE CYCLONIC FLOW DURING THE WEEKEND WERE IN FAIRLY GOOD AGREEMENT. THUS...FORECAST CONFIDENCE WAS HIGH WITH REGARD DETAILS OF CURRENT DATA BASE... ESPECIALLY WITH RESPECT TO COLD TEMPERATURES...AS LARGE MASS OF ARCTIC AIR SETTLES OVER THE REGION FOR THE WEEKEND AND BEYOND.

TODAY...LOW CLOUDS ANTICIPATED TO CONTINUE PUSHING ACROSS THE FORECAST AREA IN STRONG LOW LEVEL WESTERLY FLOW. THIS FLOW BECOMES MORE NORTHWESTERLY AS UPPER LEVEL AND SURFACE WAVE TRACKS TO OUR NORTH AND EAST. BUFKIT SOUNDINGS SUPPORT A VERY SHALLOW LOW LEVEL RELATIVE HUMIDITY SIGNATURE...TOPPED BY VERY DRY AIR AND CONSIDERABLE UPWARD VERTICAL MOTIONS THIS MORNING DUE TO STRONG WARM AIR ADVECTION.

BASED ON FORCING SIGNALS MANIFESTED IN WARM AIR ADVECTION THIS MORNING...THEN PASSAGE OF COLD FRONT THIS AFTERNOON...CANNOT RULE OUT THE POSSIBILITY FOR FREEZING DRIZZLE AS IN CURRENT DATA BASE. OF SPECIAL NOTE...MAINTAINED MAXIMUM TEMPERATURES BELOW MOS GUIDANCE PER EXISTING SNOW COVER AND CLOUDS...WHICH SHOULD TEMPER READINGS...IN SPITE OF 850MB TEMPERATURES REACHING NEARLY 10C.

TONIGHT THROUGH SUNDAY NIGHT...COLD AIR FILTERS SOUTHWARD IN EARNEST...AS 850MB TEMPERATURES DIP TO MINUS 16C TO MINUS 20C BY 00Z 28JAN07...THEN REMAIN THERE THROUGH 12Z 29JAN07. Q-G CONVERGENCE SUGGESTS A COUPLE DECENT FORCING SIGNALS DURING THE WEEKEND. THIS SIGNAL WAS GENERALLY IN THE MID/UPPER LEVELS...ALONG WITH STEEP MID LEVEL LAPSE RATES OF UP TO 6C/KM.

AS A RESULT...THERE SHOULD NOT BE TOO MUCH PROBLEM PRODUCING SNOW SHOWERS OR FLURRIES IN THE UNSTABLE COLD CYCLONIC FLOW. CURRENT SNOW PROBABILITIES MAY NEED TO BE INCREASED ONCE MORE DETAIL CAN BE ATTAINED WITH SUBSEQUENT MODEL AND OBSERVATIONAL DATA.

WIND CHILL COULD BECOME A FACTOR SATURDAY NIGHT INTO SUNDAY... MAINLY ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. SHOULD MINIMUM AND MAXIMUM TEMPERATURES NEED TO BE LOWERED...WHICH MAY CERTAINLY BE THE CASE BEFORE ALL IS SAID AND DONE...THE AFOREMENTIONED AREAS COULD BE APPROACHING WIND CHILL ADVISORY CRITERIA.

.LONG TERM...MONDAY THROUGH THURSDAY

00Z 26JAN07 MEDIUM RANGE MODELS CONTINUED TO ADVERTISE A RATHER COLD SPELL. THEREFORE...FORECAST CONFIDENCE WAS FAIRLY HIGH BASED ON CONSISTENT SIGNAL OF 850MB TEMPERATURES IN THE GFS AND ECMWF REMAINING IN THE MINUS TEENS C TO EVEN MINUS LOWER 20S C READINGS.

A COUPLE OF UPPER LEVEL AND SURFACE WAVES TRANSIT THE UPPER MISSISSIPPI VALLEY EARLY IN THE WEEK AND AGAIN AT MID WEEK. THIS SCENARIO HAS ALREADY BEEN ADDRESSED IN THE CURRENT DATA BASE...WITH LOW-END SNOW PROBABILITIES IN THESE TIME FRAMES. NO CHANGES WERE MADE TO THE EXTENDED OUTLOOK.

&&

.ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. &&

$$

THOMPSON

.DISCUSSION... 09Z SFC ANALYSIS SHOWS A STNRY BNDRY DRAPED ALONG THE LEE OF THE CENTRAL MTN CHAIN WITH AN EXPANSIVE AREA OF LOW CLOUDS TO THE EAST OF THE FRONT. LATEST WV IMAGERY SHOWS AN UPPER LOW CENTERED NEAR SAN FRANCISCO ELONGATING EAST TO WEST BETWEEN AN ARCTIC SYSTEM DIVING SOUTH OVER WESTERN CANADA AND A TROPICAL PLUME MOVING NORTHEAST OVER THE E PACIFIC. LATEST 400-200MB AIRCRAFT WINDS SHOWS A 80-110 KNOT JET STREAKING ACROSS THE DESERT SW IN THE BASE OF THE CALIFORNIA UPPER LOW.

00Z MREF/03Z SREF IN FAIRLY GOOD AGREEMENT WITH EVOLN OF THE H5 PATTERN THRU THE SHORT TERM. 00Z GFS/NAM/ECMWF/UKMET ALSO ON BOARD IN THE SHORT TERM THAT WEAK SHORT WAVE RIDGING WILL CONTINUE TO DEVELOP TO THE WEST OF NM THRU MON NIGHT. THIS SPELLS PERIODS OF HIGH CLOUDINESS FOR NM SUNDAY AND MONDAY AND WEAK LEE TROUGHING IN THE E PLAINS. EXPECT LOW CLOUDS TO DISSIPATE TODAY ACROSS THE EAST AS LEE TROUGHING DEVELOPS SW WINDS. TEMPS WILL RISE INTO LOW TO MID 40S IN MOST AREAS...STILL 5 TO 10 DEG BELOW NORMAL. MODELS THEN INDICATE A COLD FRONT TO SWING SW THRU THE NE PLAINS AND CONTINUE WEST INTO THE CENTRAL VALLEYS TUESDAY MORNING. EXPECTING EAST CANYON WINDS TO DEVELOP USHERING IN SLIGHTLY COOLER TEMPS FOR TUESDAY FROM CENTRAL VALLEYS EASTWARD. RAISED POPS ACROSS THE EAST BEHIND THE FRONT TO CHANCE AS LOW LEVEL EASTERLY FLOW UNDERCUTS MOISTENING 700-500MB SW WINDS THUS ENHANCING ISENTROPIC LIFT. FRONT THEN EXPECTED TO WASH OUT LATE TUES INTO WED AS AN AREA OF LOW PRESSURE DEVELOPS OVER THE PLAINS STATES.

MODELS SHOW MORE UNCERTAINTY WITH THE EVOLN OF THE STORM SYSTEM SLATED FOR WED AND THURS. TREND HAS BEEN FOR NORTHERN STREAM ENERGY TO DIVE MORE TO THE EAST OVER THE PLAINS STATES AND ALLOW THE SOUTHERN ENERGY TO DRAW MORE MOISTURE NORTH INTO NM THURS. THIS BRINGS US INTO THE NEXT PERIOD OF ENHANCED POPS WED OR THURS. UNDERCUT MET/MAV GUIDANCE SINCE UNCERTAINTY IS STILL HIGH WITH THIS SYSTEM. IF NORTHERN STREAM ENERGY PHASES WITH SOUTHERN STREAM WILL BE TALKING ABOUT ANOTHER SNOW STORM ACROSS NM HOWEVER IF NORTHERN STREAM CONTINUES TO TREND TO THE EAST WILL HAVE MORE RAIN/SNOW SHOWER ACTIVITY. IN ANY EVENT...MODELS SHOW UNSETTLED PATTERN WILL CONTINUE INTO THE WEEKEND STATEWIDE.

&&

.PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 46 22 44 23 / 0 0 0 5 GALLUP.......................... 43 15 41 19 / 0 0 0 5 GRANTS.......................... 46 14 44 19 / 0 0 0 10 GLENWOOD........................ 55 29 53 31 / 0 0 0 0 CHAMA........................... 39 0 35 7 / 5 0 0 20 LOS ALAMOS...................... 41 14 39 13 / 5 0 0 20 RED RIVER....................... 35 5 32 9 / 5 0 0 20 TAOS............................ 40 9 39 12 / 5 0 0 20 SANTA FE........................ 41 19 40 21 / 0 0 0 20 SANTA FE AIRPORT................ 41 20 38 22 / 0 0 0 20 ESPANOLA........................ 46 19 44 21 / 0 0 0 20 ALBUQUERQUE HEIGHTS............. 48 26 46 29 / 0 0 0 5 ALBUQUERQUE VALLEY.............. 50 22 48 28 / 0 0 0 10 ALBUQUERQUE FOOTHILLS........... 45 25 44 28 / 0 0 0 10 ALBUQUERQUE WEST MESA........... 47 25 47 29 / 0 0 0 10 SOCORRO......................... 52 27 51 28 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 40 20 41 22 / 0 0 0 20 MORIARTY/ESTANCIA............... 43 22 43 24 / 0 0 0 20 CARRIZOZO....................... 49 23 50 28 / 0 0 0 5 RUIDOSO......................... 46 25 45 24 / 0 0 0 10 RATON........................... 40 13 39 16 / 0 0 0 20 LAS VEGAS....................... 40 18 40 19 / 0 0 0 20 ROY............................. 42 24 39 17 / 0 0 0 20 CLAYTON......................... 40 23 36 16 / 0 0 0 20 SANTA ROSA...................... 46 27 44 25 / 0 0 0 20 TUCUMCARI....................... 44 24 41 25 / 0 0 0 20 FORT SUMNER..................... 46 24 45 24 / 0 0 0 20 CLOVIS.......................... 43 26 43 25 / 0 0 0 20 PORTALES........................ 46 25 45 24 / 5 0 0 20 ROSWELL......................... 48 27 50 29 / 5 0 0 10

&&

.ABQ WATCHES/WARNINGS/ADVISORIES... NONE.

&&

$$

GUYER

.SHORT TERM... ...SIGNIFICANT UPSLOPE SNOW EVENT EXPECTED ACROSS THE MOUNTAINS... ...POSSIBLE LIGHT ACCUMULATIONS ACROSS THE METRO AREAS THIS EVENING AND EARLY TONIGHT...

WATER VAPOR LOOP SHOWS A SHORT WAVE MOVING EAST THROUGH THE CAROLINAS...WITH A SHEAR AXIS ACROSS THE FORECAST AREA. THE NEXT AND MORE VIGOROUS WAVE IS DROPPING SOUTHEAST THROUGH THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-120KT SOUTHWESTERLY JET FROM THE MIDWEST INTO NEW ENGLAND...AND A 130-150KT SOUTHWESTERLY JET FROM THE NORTHERN GULF OF MEXICO THROUGH THE CAROLINAS. 11Z SURFACE ANALYSIS PLACED A COLD FRONT FROM THE WESTERN GULF OF MEXICO TO NEAR CHARLOTTESVILLE...THEN EAST ACROSS THE DELMARVA. A 1029MB ANTICYCLONE WAS LOCATED ACROSS THE CENTRAL CONUS...WITH THE ARCTIC COLD FRONT STRETCHED FROM THE UPPER MIDWEST EAST ACROSS THE GREAT LAKES AND NORTH INTO NEW ENGLAND.

RAIN HAS DEVELOPED ON THE UPPER LEVEL SHEAR AXIS ACROSS THE CENTRAL FORECAST AREA...WHICH WILL CONTINUE TO PIVOT SOUTH AND EAST AFFECTING MAINLY LOWER SOUTHERN MARYLAND THIS AFTERNOON. A FEW HUNDREDTHS OF AN INCH OF RAIN WERE RECORDED THIS MORNING ACROSS THE WASHINGTON AND BALTIMORE METRO AREAS...WITH SIMILAR AMOUNTS EXPECTED FURTHER SOUTH.

A SIGNIFICANT UPSLOPE SNOW EVENT IS UNDERWAY ACROSS THE WESTERN MOUNTAINS. BAYARD AND MOUNT STORM CHECKED IN WITH 1-1.5" ALREADY EARLY THIS MORNING...WITH LIQUID EQUIVALENT AT MOUNT STORM OF 0.07" (20 TO 1 SNOW RATIO). THE NAM HAS BEEN VERY CONSISTENT WITH INDICATING ABOUT A HALF INCH OF LIQUID EQUIVALENT THROUGH 12Z MONDAY...AND THE SHORT RANGE ENSEMBLES ALSO HAVE BEEN CLUSTERED BETWEEN 0.5-0.7" FOR THE PAST FEW RUNS AT KEKN. THE DENDRITIC SNOW GROWTH LAYER IS ALSO WITHIN THE VERTICAL MOTION FORCED BY THE TERRAIN. WITH REPORTS OF HEAVY SNOW AND THE ARRIVAL OF UNSTABLE AIR LATE THIS AFTERNOON...HAVE UPGRADED TO A WINTER STORM WARNING ACROSS THE FAR NORTHWEST 3 COUNTIES...AND ISSUED A SNOW ADVISORY ACROSS HIGHLAND AND PENDLETON COUNTIES.

IN BETWEEN THE UPSLOPE SNOW AND SHEAR AXIS RAIN...NOT SEEING MUCH FORCING SO HAVE REMOVED POPS THIS AFTERNOON.

THIS EVENING AND EARLY TONIGHT APPEAR INTERESTING WITH THE ARRIVAL OF A VIGOROUS SHORT WAVE. INSTABILITY IS VERY APPARENT WITH 7-9C/KM LAPSE RATES FROM THE SURFACE TO ABOVE 700MB. EXPECT SNOW SHOWERS TO ARRIVE FROM THE NORTH AND WEST THIS EVENING WITH THE INSTABILITY. MODEL GUIDANCE AND MOS DO NOT PRESENT MUCH QPF OR PROBABILITY OF PRECIPITATION...HOWEVER THIS IS A CASE FOR GOING WELL ABOVE GUIDANCE. IT DOES NOT TAKE MUCH MOISTURE TO DEVELOP PRECIPITATION WITHIN AN UNSTABLE AIRMASS ALONG A VIGOROUS SHORT WAVE. HAVE INCREASED POPS TO 50 PERCENT FOR NOW AND WILL LOOK AT FURTHER OBSERVATIONS FOR POSSIBLY INCREASING THEM FURTHER AND INCLUDING LIGHT ACCUMULATIONS. IT COULD SNOW HEAVILY FOR A BIT IN SOME PLACES AS THE DENDRITIC SNOW GROWTH LAYER IS WITHIN THE UNSTABLE 900-700MB LAYER.

&&

.AVIATION... WINDS BACK FROM NORTHERLY TO NORTHWEST AS LOW PRESSURE DEVELOPS WELL OFF THE EAST COAST (AND MAY BEGIN TO GUST AS THE GRADIENT INCREASES). SHEAR AXIS SUPPORTING LIGHT RAIN AND MVFR CIGS/VFR VISBY WILL TRANSLATE TO THE SOUTHEAST OF THE METRO TERMINALS BY MIDDAY. EXPECT SCT-BKN040 TO PERSIST THROUGH THE AFTERNOON.

&&

.MARINE... SMALL CRAFT ADVISORY IN EFFECT. OBSERVED WIND GUSTS IN THE MOUNTAINS ARE BETWEEN 15-20KTS. OBSERVED WINDS JUST ABOVE THE MIX LAYER ARE 20KT ON THE 12Z KIAD RAOB.

00Z ETA/06Z MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS BETWEEN 8-12KTS TODAY. 06Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS SHOW ADDITIONAL MOMENTUM TRANSFER OF 15-20KTS. WITH STRENGTHENING GRADIENT THIS EVENING...WILL MAINTAIN THE SMALL CRAFT ADVISORY DURING THE DAY TODAY WITH 20KT WIND GUSTS.

&&

.TIDES... WATER LEVELS ARE CURRENTLY LESS THAN A HALF FOOT ABOVE ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING TOWARD A FULL MOON IN EARLY FEBRUARY.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES REMAIN AT CURRENT DEPARTURES OR GRADUALLY RETURN TO ASTRONOMIC PREDICTIONS THROUGH THIS TONIGHT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR MDZ501.

VA...SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR VAZ021.

WV...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR WVZ501-503.

SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR WVZ054.

MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST MONDAY FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI

.UPDATE...NORTHERN MICHIGAN THIS MORNING DOMINATED BY COLD NORTH TO NORTHEAST WINDS BETWEEN MID LEVEL TROUGH AXIS PASSING BY TO THE SOUTH AND SURFACE RIDGING BUILDING INTO THE WESTERN LAKES. IMPRESSIVE OVER WATER INSTABILITY (DELTA T VALUES ON THE ORDER OF 20C) AND REMNANT MID LEVEL MOISTURE KICKING OFF NORTHEAST TO SOUTHWEST ORIENTED LAKE SNOW SHOWERS OVER AREAS ALONG AND WEST OF GRAND TRAVERSE BAY AND ALONG THE LAKE HURON SHORELINE. RECENT CALLS TO SPOTTERS IN WARNING AND ADVISORY AREAS SHOWS ABOUT 5 INCHES OF NEW SNOW OVER PARTS OF LEELANAU COUNTY WITH MUCH LESSER AMOUNTS ELSEWHERE. SOME LIGHT SYNOPTIC SNOW ASSOCIATED WITH AFOREMENTIONED SHORTWAVE OVER SOUTHERN AREAS IS STEADILY DROPPING TO THE SOUTHEAST. ATTENTION THIS MORNING REMAINS CENTERED ON LAKE EFFECT SNOWS AND ASSOCIATED LAKE SNOW HEADLINES.

REST OF TODAY...SYNOPTIC SUPPORT AND MOISTURE QUICKLY ROTATES SOUTHEAST OUT OF THE AREA AS SOUTHERN LAKE MICHIGAN SHORTWAVE RACES EAST THROUGH SOUTHERN MICHIGAN. WESTERN LAKES SURFACE RIDGING CONTINUES TO BUILD INTO THE AREA BEHIND DEPARTING SYSTEM. SOME EVIDENCE OF THIS ALREADY OCCURRING WITH LAKE SUPERIOR BANDS ONCE AGAIN BECOMING ORIENTED NORTHWEST TO SOUTHEAST AS 1000MB-850MB WINDS BACK AROUND TO NORTHWESTERLY. INVERSION HEIGHTS ALSO SHOWING INFLUENCE OF INCREASED MID LEVEL SUBSIDENCE WITH MORNING ACARS SOUNDINGS OUT OF SAWYER IN THE CENTRAL U.P AND RHINELANDER IN NORTH CENTRAL WISCONSIN SHOWING INVERSION HEIGHTS AT ONLY 850MB (ABOUT 4.5KFT). EXPECT NORTHERN MICHIGAN WINDS TO SLOWLY BACK AROUND TO NORTHWEST DURING THE AFTERNOON...DIRECTING BANDS ONCE AGAIN FARTHER INLAND. OVERALL DIMINISHING TREND EXPECTED TO CONTINUE...DESPITE EXTREME OVER WATER INSTABILITY...WITH CRASHING INVERSION HEIGHTS AND 850MB-700MB MOISTURE DROPPING TO <40 PERCENT. BASED OFF CALLS AND EXPECTED TRANSIENT AND WEAKENING NATURE OF BANDS...WILL DROP MANISTEE COUNTY (ONLY HAD ABOUT AN INCH SO FAR) AND DOWNGRADE BENZIE AND GRAND TRAVERSE TO AN ADVISORY. COULD SEE LOCALIZED WARNING CRITERIA AMOUNT JUST WEST OF THE WEST ARM OF GRAND TRAVERSE BAY WHERE BETTER BANDING HAS SET UP THIS MORNING. HOWEVER...EXTREME LOCALIZED NATURE OF EVENT DOES NOT WARRANT A WARNING. WILL LEAVE LEELANAU COUNTY AS IS WITH RECENT 5 INCH REPORT AND SEVERAL BANDS YET TO TRAVERSE THE AREA. OTHERWISE...SNOW SHOWER THREAT WILL ONCE AGAIN INCREASE ALONG AND WEST OF INTERSTATE 75 OVER THE NORTHERN LOWER LATER THIS AFTERNOON AND EVENING AS REMNANT BANDS PROPAGATE FARTHER INLAND. ANY ACCUMULATIONS IN THIS AREA WILL BE MINIMAL. LAKE HURON BANDS WILL HANG ON A COUPLE HOURS MORE UNTIL THEY MOVE OFFSHORE WITH PERHAPS AN ADDITIONAL INCH OF ACCUMULATION. ACROSS EASTERN UPPER...COLD NORTHEAST DRAINAGE FLOW HAS KEPT BANDS WELL WEST OF CHIPPEWA COUNTY. MUCH LIKE THE NORTHERN LOWER...BANDS WILL MOVE BACK IN THIS AFTERNOON IN RESPONSE TO BACKING WINDS. COULD SEE UP TO AN INCH NEAR WHITEFISH POINT WITH LONGER LAKE SUPERIOR FETCH PARTIALLY OVERCOMING OTHER NEGATIVE PARAMETERS. AS FOR TEMPERATURES...DRAINAGE FLOW HAS SPREAD AS FAR SOUTH AS NORTHERN SECTIONS OF THE NORTHERN LOWER RESULTING IN TEMPERATURES A FEW DEGREES BELOW ZERO OVER EASTERN SECTION OF EASTERN UPPER MICHIGAN AND NEAR THE TIP OF THE MIT. HENCE...HAVE LOWERED HIGHS A COUPLE DEGREES IN THESE AREAS.

UPDATED WINTER WEATHER PRODUCTS/GRIDS/ZONES/NEARSHORES OUT SHORTLY.

MSB &&

.PREV DISCUSSION...ISSUED AT 410 AM EST SUN JAN 28 2007

IR/WATER VAPOR SATELLITE IMAGERY SHOWING SHORT WAVE CENTER AND AREA OF COOLER CLOUD TOPS PROGRESSING THROUGH SOUTHWEST WISCONSIN HEADING TOWARD ILLINOIS THIS MORNING. AT THE SFC... TROUGH/BACKDOOR COLD FRONT CONTINUES TO PROGRESS SOUTHWARD THROUGH NRN LOWER MICHIGAN NOW ROUGHLY ALONG THE M-55 CORRIDOR WHILE LAST BIT OF SYNOPTIC SNOWFALL ALSO SLIDING SOUTHWARD THROUGH NRN LOWER MICHIGAN. HEAVIEST LAKE EFFECT BANDING HAS SHIFTED INTO THE GRAND TRAVERSE BAY AREA AS THE LOW LEVEL FLOW BEHIND THE TROUGH SHIFTS TO THE NORTH. BUT INTERESTING TO NOTE THE MESO-LOW FEATURE THAT HAS DEVELOPED WITHIN THE SHARP TROUGH NOW SLIDING SOUTHWARD THROUGH GRAND TRAVERSE/KALKASKA COUNTIES. SOME ADDITIONAL LAKE BANDING NOTED COMING OFF LAKE HURON INTO PRESQUE ISLE COUNTY AND INTO THE HIGHER TERRAIN.

MAIN FORECAST CONCERN REVOLVES AROUND DISPOSITION OF ONGOING WARNINGS/ADVISORIES.

TODAY...FIRST OFF...WILL CONTINUE TO CARRY HIGHER POPS OVER MUCH OF NRN LOWER MICHIGAN THIS MORNING AS LAST BIT OF SYNOPTIC SNOWFALL (AND MESO-LOW FEATURE) SLIDES SOUTH WITH THE SHARP SFC TROUGH... COUPLED WITH NNE FLOW OFF LAKE HURON PRODUCING DECENT LIGHT SNOW COVERAGE ACROSS THE CENTRAL AND EASTERN COUNTIES. HOWEVER...BELIEVE SIGNIFICANT ACCUMULATING SNOW IS DONE FOR THE SO CALLED "BIG 5 COUNTIES" AND WILL ALLOW HEADLINES TO EXPIRE WITH MORNING FORECAST ISSUANCE. MAIN STORY WILL BE THE CONTINUING LAKE EFFECT EVENT AS MEAN 1000-850 MB FLOW TURNS ROUGHLY TO THE NORTH AND COLDER AIR SETTLES INTO NRN MICHIGAN. FROM A LAKE EFFECT STANDPOINT...CONDITIONS LOOKING GOOD FOR HEAVY LAKE EFFECT SNOWFALL THROUGH MID TO LATE AFTERNOON. LAKE-850 MB DELTA T/S AROUND 20C/WEAK OR NON EXISTENT INVERSIONS/ ABUNDANT LOW LEVEL MOISTURE AROUND THROUGH MID AFTERNOON. ONLY HINDRANCE WILL BE THE MEAN FLOW WHICH CURRENT LAPS DATA SHOWS IS VEERING BEHIND THE TROUGH TO ~020/030 DEGREES ON THE MICHIGAN SIDE THIS MORNING...AND SUGGESTS LEELANAU/BENZIE COUNTIES GET THE BULK OF HEAVIEST SNOWFALL. HOWEVER...FLOW IS FORECAST TO BACK TO ~360 DEGREES EARLY IN THE AFTERNOON PULLING SNOW BANDS BACK TOWARD GRAND TRAVERS COUNTY. AT THIS POINT WILL LET ONGOING WARNINGS/ADVISORY FOR GRAND TRAVERSE/LEELANAU/BENZIE/MANISTEE COUNTIES RIDE...AND LET THE EVENT PLAY OUT FOR AWHILE. AS FAR AS ACCUMULATIONS ARE CONCERNED: BASED ON THE PARAMETERS WE CERTAINLY SHOULD SEE INCH PER HOUR TYPE SNOW SHOWERS THIS MORNING THROUGH MID AFTERNOON PRODUCING OVERALL ACCUMULATIONS IN THE 3-6 INCH RANGE IN THE MOST FAVORED AREAS (AGAIN LEELANAU/BENZIE COUNTIES) AND LOCALIZED HIGHER AMOUNTS CERTAINLY A POSSIBILITY. WILL OPEN THE RANGE A BIT MORE FOR GRAND TRAVERSE COUNTY (2-6) GIVEN THE EARLY NNE FLOW TARGETING HIGHEST ACCUMS OVER WESTERN PORTION OF THE COUNTY. FOR MID TO LATE AFTERNOON...STRONG DRYING ALOFT STILL INDICATED WITH 850-700 MEAN RH LOWERING TO <50 PERCENT AS HIGH PRESSURE/ANTICYCLONIC FLOW NOSES INTO THE NRN MICHIGAN. LOW LEVEL FLOW LOOKING TO BACK TOWARD NNW OR NW BY EARLY EVENING WHICH WILL PULL REMAINING SNOW SHOWERS BACK TOWARD THE I-75 CORRIDOR LATE IN THE DAY. HOWEVER...DESPITE THE GREAT OVER LAKE INSTABILITY...THE OTHER MENTIONED FACTORS SHOULD TEMPER SNOW SHOWER INTENSITIES BY THAT POINT. THUS DO NOT FORESEE ANY ADDITIONAL HEADLINES BEYOND THE CURRENT ONES.

LAKE HURON SIDE...AS MENTIONED ABOVE NNE FLOW WILL CONTINUE TO PRODUCE ACCUMULATING LAKE SNOW SHOWERS INTO PRESQUE ISLE AND ALPENA COUNTIES EARLY ON...BUT EVENTUALLY SHIFTING TOWARD THE COAST (OR OFFSHORE) AS WINDS BACK MORE NORTHERLY. FURTHER BACKING OF THE WIND TOWARD IN THE AFTERNOON MAY ESTABLISH A LAKE SUPERIOR CONNECTION WITH SOME DECENT SNOW SHOWERS SKIRTING ALONG THE SHORELINE STRETCH OF PRESQUE ISLE COUNTY. BUT OVERALL...WITH THE SHIFTING WIND PATTERN WILL KEEP ACCUMULATIONS ON THE LIGHTER SIDE ACROSS NE LOWER MICHIGAN.

FINALLY...EASTERN UPPER MICHIGAN. NE FLOW PRETTY MUCH KEEPING EASTERN UPPER MICHIGAN OUT OF THE ACTION EARLY THIS MORNING. BUT FLOW IS EXPECTED TO BACK TOWARD NORTH WHICH WOULD PULL SOME SNOW SHOWERS BACK TOWARD WHITEFISH POINT...AND EVENTUALLY TO NW THIS AFTERNOON. BUT...DRYING ALOFT WILL ALREADY BE OVERSPREADING LAKE SUPERIOR THIS MORNING AND SHOULD KEEP OVERALL ACCUMULATIONS AT BAY (2 OR 3 INCHES AT BEST AROUND WHITEFISH POINT).

TONIGHT...FURTHER DRYING CONTINUES WHILE LOW LEVEL RIDGING SLIDES INTO THE WESTERN GREAT LAKES...AND LOW LEVEL FLOW BACKS FROM NW IN THE EVENING AROUND TO ROUGHLY WEST BY MONDAY MORNING. INTERESTING TO NOTE HOWEVER...LAKE INDUCED TROUGHING FORECAST TO REDEVELOP FROM EASTERN LAKE SUPERIOR DOWN ACROSS NRN LAKE HURON OVERNIGHT...WHICH IS REASONABLE GIVEN THE COLD AIRMASS ACROSS THE LAKES. SO ALTHOUGH LAKE EFFECT PARAMETERS NOT NECESSARILY CONDUCIVE TO HEAVY SNOW SHOWERS PRIMARILY DUE TO THE DRY AND COLD AIRMASS...LAKE TROUGHING MIGHT BE ENOUGH TO FOCUS SOME HEAVIER SNOW SHOWERS AND AN INCH OR TWO ACROSS CHIPPEWA COUNTY ESPECIALLY THE WHITEFISH POINT AREA. FOR NRN LOWER MICHIGAN...BACKING LOW LEVEL FLOW EXPECTED TO MIGRATE SNOW SHOWERS OFF THE LAKE INLAND AND NORTHWARD DURING THE NIGHT...WITH AN INCH OR TWO TOTAL ACCUMULATION IN THE MOST FAVORED AREAS.

MONDAY...NEXT IN A SERIES OF WAVES/CLIPPER SYSTEMS TRAVERSES THROUGH THE WESTERN GREAT LAKES LATE MONDAY THROUGH MONDAY NIGHT GENERATING SOME SYNOPTIC SNOWFALL ACROSS THE REGION. AT THIS POINT...NAM/GFS DISAGREE OVER TRACK OF THIS SYSTEM WITH THE NAM MUCH FARTHER SOUTH KEEPING ANY SYNOPTIC SNOWFALL OUT OF NRN MICHIGAN ALTOGETHER. GFS AS WELL AS THE ECMWF AND UKMET (WHICH IS EVEN FURTHER NORTH) SUGGEST SOME LIGHT SNOWFALL MOVING THROUGH NRN MICHIGAN WITH THIS SYSTEM LATE MONDAY AND MONDAY NIGHT. MEANWHILE...LIGHT LAKE EFFECT SNOW SHOWERS WILL MOST CERTAINLY BE ONGOING GIVEN THE OVER LAKE INSTABILITY...AND IF FURTHER NORTH TRACK OF UPCOMING SYSTEM IS CORRECT WOULD EXPECT SOME SORT OF UP TICK IN LAKE EFFECT INTENSITIES. WILL TREND FORECAST TOWARD THIS IDEA FOR NOW IF FOR NO OTHER REASON THAN MODEL CONSENSUS BUT STILL KEEP POPS IN THE CHANCY CATEGORY GIVEN THE UNCERTAINTY.

TUESDAY THROUGH THURSDAY...SOUNDING LIKE A BROKEN RECORD...BUT NO CHANGES IN THE ONGOING COLD PATTERN THROUGH THE WEEK. BLOCKING RIDGE PATTERN IN THE EASTERN PACIFIC ONLY STRENGTHENS...WHILE DOWNSTREAM LONG WAVE TROUGHING ACROSS CENTRAL AND EASTERN NAOM DEEPENS. WITHIN THE LONG WAVE TROUGH PATTERN...SERIES OF SHORT WAVES EXPECTED TO SLIDE THROUGH THE REGION DURING THIS TIME REINFORCING THE COLD AIR OVER THE GREAT LAKES AND BRINING PERIODS OF ENHANCED SNOW/LAKE EFFECT SNOW TO THE REGION. FIRST WAVE/SFC LOW SLATED TO ARRIVE LATE MONDAY INTO EARLY TUESDAY. AS IT STANDS...THIS SYSTEM IS EXPECTED TO BRING A ROUND OF SYNOPTIC SNOWFALL (PERHAPS A COUPLE OF INCHES) PRIMARILY TO LOWER MICHIGAN FOLLOWED BY LAKE EFFECT SNOW CONCERNS TUESDAY AND TUESDAY NIGHT. A BRIEF REPRIEVE AGAIN FOR WEDNESDAY (STILL LIGHT LAKE EFFECT) AS HIGH PRESSURE AND DRIER AIR PASS THROUGH. ANOTHER WAVE LATE WEDNESDAY INTO THURSDAY WHICH WILL BRING THE SAME CONCERNS AS TUESDAY. THIS GENERAL IDEA ALREADY PORTRAYED IN THE CURRENT FORECAST WITH FINER DETAILS TO BE WORKED OUT AS WE GET CLOSER TO THE EVENTS. THUS...NO SIGNIFICANT CHANGES ANTICIPATED AT THIS TIME.

ADAM

&&

.APX WATCHES/WARNINGS/ADVISORIES...LAKE EFFECT SNOW WARNING THROUGH THIS AFTERNOON...MIZ020. LAKE EFFECT SNOW ADVISORY THROUGH THIS AFTERNOON...MIZ025-026.

&&

$$

.UPDATED... AS OF 10 AM THE PRIMARY SNOW BAND HAS MOVED OFF SHORE FOR MOST OF THE GRR CWA. THERE IS A MESO-LOW JUST OFF SHORE OF HOLLAND MOVING DUE SOUTH. TAMDAR SOUNDINGS FROM WEST MICHIGAN SHOW WINDS OUT OF THE NORTHEAST OR EVEN EAST BELOW 10000 FT. THERE IS SHARP SURFACE TROUGH DROPPING SOUTH THROUGH LOWER MICHIGAN. AT 10 AM IT WAS NEAR INTERSTATE 96. OVERALL DUE TO THE NORTH NORTHEAST WINDS BEHIND THE TROUGH THROUGH 800 MB MOST OF TODAY... THE HEAVY SNOW BAND WILL REMAIN OFF SHORE. EXTREME EASTERN VAN BUREN COUNTY MAY SEE ANOTHER PERIOD OF MODERATE TO HEAVY SNOW AS THE MESO LOW NEAR HOLLAND MOVES THROUGH THE AREA. TIMING TOOLS SHOW THIS WOULD BE BETWEEN 11 AM AND NOON. AS A RESULT OF THE PRIMARY SNOW BAND STAYING OFF SHORE AND ONLY LIGHT SNOW SHOWERS INLAND ASSOCIATED WITH THE TROUGH... I PLAN ON DROPPING MOST OF OUR HEADLINES AROUND 11 AM. I MAY LEAVE VAN BUREN IN A WARNING TILL 1 PM...ENOUGH TIME TO ALLOW THE MESO LOW FEATURE TO MOVE THROUGH.

I DO EXPECT THE LAKE CONVERGENCE BAND TO MOVE ON SHORE THIS EVENING OVER MOST OF SOUTHWEST MICHIGAN BUT BY THEN THE INVERSION HEIGHTS WILL HAVE CRASHED AND THE FEATURE WILL BE FALLING APART. SO I SEE NO HEADLINE ISSUES THERE.

&& .GRR WATCHES/WARNINGS/ADVISORIES...LAKE EFFECT SNOW WARNING IN EFFECT THROUGH SUNDAY EVENING FOR OTTAWA...ALLEGAN...VAN BUREN... KALAMAZOO AND CALHOUN COUNTIES.

LAKE EFFECT SNOW ADVISORY MASON...OCEANA...AND MUSKEGON COUNTIES THROUGH SUNDAY EVENING.

SMALL CRAFT ADVISORY FOR THE NEARSHORE WATERS THROUGH SUNDAY NIGHT.

&&

$$

WDM

.SHORT TERM /TONIGHT THROUGH MONDAY/... ...SIGNIFICANT UPSLOPE SNOW EVENT EXPECTED ACROSS THE MOUNTAINS... ...POSSIBLE LIGHT ACCUMULATIONS ACROSS THE METRO AREAS THIS EVENING AND EARLY TONIGHT...

WATER VAPOR LOOP SHOWS A SHORT WAVE MOVING EAST THROUGH THE CAROLINAS...WITH A SHEAR AXIS ACROSS THE FORECAST AREA. THE NEXT AND MORE VIGOROUS WAVE IS DROPPING SOUTHEAST THROUGH THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-120KT SOUTHWESTERLY JET FROM THE MIDWEST INTO NEW ENGLAND...AND A 130-150KT SOUTHWESTERLY JET FROM THE NORTHERN GULF OF MEXICO THROUGH THE CAROLINAS. 11Z SURFACE ANALYSIS PLACED A COLD FRONT FROM THE WESTERN GULF OF MEXICO TO NEAR CHARLOTTESVILLE...THEN EAST ACROSS THE DELMARVA. A 1029MB ANTICYCLONE WAS LOCATED ACROSS THE CENTRAL CONUS...WITH THE ARCTIC COLD FRONT STRETCHED FROM THE UPPER MIDWEST EAST ACROSS THE GREAT LAKES AND NORTH INTO NEW ENGLAND.

A SIGNIFICANT UPSLOPE SNOW EVENT IS UNDERWAY ACROSS THE WESTERN MOUNTAINS. BAYARD AND MOUNT STORM CHECKED IN WITH 1-1.5" ALREADY EARLY THIS MORNING. THE NAM HAS BEEN VERY CONSISTENT WITH INDICATING ABOUT A HALF INCH OF LIQUID EQUIVALENT THROUGH 12Z MONDAY...AND THE SHORT RANGE ENSEMBLES ALSO HAVE BEEN CLUSTERED BETWEEN 0.5-0.7" FOR THE PAST FEW RUNS AT KEKN. THE DENDRITIC SNOW GROWTH LAYER IS ALSO WITHIN THE VERTICAL MOTION FORCED BY THE TERRAIN. WITH REPORTS OF HEAVY SNOW AND THE ARRIVAL OF UNSTABLE AIR LATE THIS AFTERNOON...HAVE A WINTER STORM WARNING ACROSS THE FAR NORTHWEST 3 COUNTIES...AND A SNOW ADVISORY ACROSS HIGHLAND AND PENDLETON COUNTIES.

THIS EVENING AND EARLY TONIGHT APPEAR INTERESTING WITH THE ARRIVAL OF A VIGOROUS SHORT WAVE. INSTABILITY IS VERY APPARENT WITH 7-9C/KM LAPSE RATES FROM THE SURFACE TO ABOVE 700MB. EXPECT SNOW SHOWERS TO ARRIVE FROM THE NORTH AND WEST THIS EVENING WITH THE INSTABILITY. MODEL GUIDANCE AND MOS DO NOT PRESENT MUCH QPF OR PROBABILITY OF PRECIPITATION...HOWEVER THIS IS A CASE FOR GOING WELL ABOVE GUIDANCE. IT DOES NOT TAKE MUCH MOISTURE TO DEVELOP PRECIPITATION WITHIN AN UNSTABLE AIRMASS ALONG A VIGOROUS SHORT WAVE. IT COULD SNOW HEAVILY FOR A BIT IN SOME PLACES AS THE DENDRITIC SNOW GROWTH LAYER IS WITHIN THE UNSTABLE 900-700MB LAYER.

APPEARS BEST CHANCES FOR ACCUMULATION ARE ALONG AND EAST OF INTERSTATE 95...WHERE THE INCOMING INSTABILITY WILL INTERSECT REMAINING SHEAR AXIS ALOFT. TO NARROW IT DOWN FURTHER...THE BALTIMORE METRO AREA HAS THE BEST CHANCES OF AN INCH OR GREATER. FOR NOW HAVE MENTIONED AN INCH OF SNOW...BUT EVENING SHIFT WILL HAVE TO MONITOR RADAR TRENDS FOR A POSSIBLE SNOW ADVISORY AS INSTABILITY COMES IN TO SEE HOW MUCH OF A PLAYER THE SHEAR AXIS IS FOR FOCUSING SNOW SHOWERS. HAVE ISSUED A SPECIAL WEATHER STATEMENT AS STRONG INSTABILITY SHOULD PROVIDE FOR HIGH IMPACT SUB ADVISORY CONDITIONS WITH BRIEF REDUCTION IN VISIBILITIES BELOW A HALF MILE.

WINDS INCREASE OVERNIGHT AS A CYCLONE QUICKLY DEVELOPS WELL OFFSHORE AND THE GRADIENT STRENGTHENS WITHIN STRONG COLD ADVECTION REGIME.

BUILDING HEIGHTS WILL ALLOW ANTICYCLONIC FLOW TO BUILD IN...CAUSING UPSLOPE SNOW SHOWERS TO DISSIPATE MONDAY. DOWNSLOPE FLOW...ALBEIT WEAKENING THROUGH THE DAY...SHOULD BE ENOUGH TO ERODE LOW LEVEL MOISTURE FROM THE SHENANDOAH VALLEY EASTWARD DURING THE DAY. WENT BELOW MOS GUIDANCE FOR HIGH TEMPERATURES WITH PRESENCE OF STRONG COLD ADVECTION AND SOME AREAS OF ANTICIPATED LIGHT SNOW ACCUMULATION OVERNIGHT.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... RELATIVELY QUIET EXTENDED...UNTIL THE END OF THE WORK-WEEK.

ZONAL FLOW IN THE MID LEVELS AT THE BEGINNING OF THE PERIOD. THIS PRETTY MUCH WILL BE STATUS QUO UNTIL THURSDAY. SEVERAL PIECES OF SHORTWAVE ENERGY TRAVEL EAST WITHIN THE FLOW...WITH TWO NOTABLE SHORTWAVES...ONE LATE TUESDAY/WEDNESDAY AND THE OTHER ON THURSDAY. THE ZONAL FLOW WILL TURN MORE SOUTHWEST LATER THURSDAY AS A TROUGH DIGS OVER THE WEST-CENTRAL PART OF THE COUNTRY. THE LONGWAVE TROUGH WILL MOVE EAST THROUGH FRIDAY BEFORE SETTING UP ALONG THE EAST COAST ON SATURDAY.

HIGH PRESSURE WILL BE BUILDING IN MONDAY EVENING. A FRONTAL BOUNDARY COMES TROUGH ON TUESDAY...BUT PRECIP REMAINS CONFINED TO WEST OF THE BLUE RIDGE. UPSLOPE SNOW SHOWERS WILL CONTINUE THROUGH LATE TUESDAY/EARLY WEDNESDAY. MOISTURE BEGINS TO INCREASE ON THURSDAY AHEAD OF THE NEXT FRONTAL BOUNDARY AND A DEVELOPING COASTAL LOW PRESSURE SYSTEM. THE COASTAL LOW IS EXPECTED TO MOVE UP THE EAST COAST ON FRIDAY. HIGH PRESSURE BUILDS IN FOR THE WEEKEND.

DID NOT REALLY DEVIATE FROM GUIDANCE FOR MOST OF THE EXTENDED...JUST MADE SOME MINOR TWEAKS. THERE ARE SOME INDICATIONS OF A WINTRY MIX ON FRIDAY W OF THE BLUE RIDGE...AND WILL HAVE RN/SN MIX FOR NOW.

&&

.AVIATION... STRONG MID LEVEL INSTABILITY WILL ENTER THE REGION FROM THE NORTH AND WEST THIS EVENING...ALLOWING CONVECTIVE SNOW SHOWERS TO DEVELOP THROUGH THE FIRST PORTION OF THE NIGHT. LIFR VISIBILITIES AND MVFR CEILINGS WILL BE POSSIBLE WITHIN THE HEAVIER SNOW SHOWERS...WHICH WILL BE ENDING FROM WEST TO EAST BEHIND THE SHORT WAVE BEGINNING AROUND MIDNIGHT. STRONG COLD ADVECTION WILL MAINTAIN STRONG NORTHWEST WIND GUSTS THROUGH THE NIGHT...UNTIL THE GRADIENT RELAXES MONDAY MORNING.

&&

.MARINE... SMALL CRAFT ADVISORY IN EFFECT. OBSERVED WIND GUSTS ALONG AND WEST OF THE BLUE RIDGE ARE 20KTS.

12Z ETA/MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS INCREASE TO 20KT LATE TONIGHT AND MONDAY. 12Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS SHOW ADDITIONAL MOMENTUM TRANSFER INCREASE TO JUST OVER 30KT LATE TONIGHT. WITH STRENGTHENING GRADIENT AS A CYCLONE QUICKLY DEVELOPS OFF THE COAST THIS EVENING AND STRONG DYNAMICS PASSING OVERHEAD...WILL GO SLIGHTLY MORE PESSIMISTIC THAN GUIDANCE AND RAISE A GALE WARNING FOR 35KT WIND GUSTS THROUGH 10AM.

SMALL CRAFT CONDITIONS ARE STILL POSSIBLE TUESDAY INTO WEDNESDAY BEHIND THE FRONTAL BOUNDARY. HAVE INCREASED WINDS TO AROUND 15 KTS OVER THE WATERS...SOME 20KT MAY SHOW UP IN THE BAY.

AS THE COASTAL LOW TRAVELS UP THE EASTERN SEABOARD ON FRIDAY/SATURDAY WINDS MAY ONCE AGAIN INCREASE TO SMALL CRAFT ADVISORY LEVELS.

&&

.TIDES... WATER LEVELS ARE CURRENTLY ABOUT A HALF FOOT ABOVE ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING TOWARD A FULL MOON IN EARLY FEBRUARY (79% FULL).

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES REMAIN AT CURRENT DEPARTURES OR GRADUALLY RETURN TO ASTRONOMIC PREDICTIONS THROUGH TONIGHT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR MDZ501.

WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST MONDAY FOR MDZ501.

VA...WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST MONDAY FOR VAZ021.

SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR VAZ021.

WV...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR WVZ501-503.

WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST MONDAY FOR WVZ054-501-503.

SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR WVZ054.

MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ530>537.

SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EST MONDAY FOR ANZ530>537.

GALE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST MONDAY FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/TIDES...ROGOWSKI LONG TERM...LISTEMAA MARINE...ROGOWSKI/LISTEMAA

.UPDATE...IMPROVED SKY COVER MANY W AND N ZONES FOR THIS PM. KEPT MENTION OF LOW CLOUDS AND SOME FOG OVER EC AND SE ZONES THROUGH EARLY TO MID PM AND ADJUSTED TEMPS DOWN. 40

&&

.PREV DISCUSSION...300 AM MST SUN JAN 28 2007... 09Z SFC ANALYSIS SHOWS A STNRY BNDRY DRAPED ALONG THE LEE OF THE CENTRAL MTN CHAIN WITH AN EXPANSIVE AREA OF LOW CLOUDS TO THE EAST OF THE FRONT. LATEST WV IMAGERY SHOWS AN UPPER LOW CENTERED NEAR SAN FRANCISCO ELONGATING EAST TO WEST BETWEEN AN ARCTIC SYSTEM DIVING SOUTH OVER WESTERN CANADA AND A TROPICAL PLUME MOVING NORTHEAST OVER THE E PACIFIC. LATEST 400-200MB AIRCRAFT WINDS SHOWS A 80-110 KNOT JET STREAKING ACROSS THE DESERT SW IN THE BASE OF THE CALIFORNIA UPPER LOW.

00Z MREF/03Z SREF IN FAIRLY GOOD AGREEMENT WITH EVOLN OF THE H5 PATTERN THRU THE SHORT TERM. 00Z GFS/NAM/ECMWF/UKMET ALSO ON BOARD IN THE SHORT TERM THAT WEAK SHORT WAVE RIDGING WILL CONTINUE TO DEVELOP TO THE WEST OF NM THRU MON NIGHT. THIS SPELLS PERIODS OF HIGH CLOUDINESS FOR NM SUNDAY AND MONDAY AND WEAK LEE TROUGHING IN THE E PLAINS. EXPECT LOW CLOUDS TO DISSIPATE TODAY ACROSS THE EAST AS LEE TROUGHING DEVELOPS SW WINDS. TEMPS WILL RISE INTO LOW TO MID 40S IN MOST AREAS...STILL 5 TO 10 DEG BELOW NORMAL. MODELS THEN INDICATE A COLD FRONT TO SWING SW THRU THE NE PLAINS AND CONTINUE WEST INTO THE CENTRAL VALLEYS TUESDAY MORNING. EXPECTING EAST CANYON WINDS TO DEVELOP USHERING IN SLIGHTLY COOLER TEMPS FOR TUESDAY FROM CENTRAL VALLEYS EASTWARD. RAISED POPS ACROSS THE EAST BEHIND THE FRONT TO CHANCE AS LOW LEVEL EASTERLY FLOW UNDERCUTS MOISTENING 700-500MB SW WINDS THUS ENHANCING ISENTROPIC LIFT. FRONT THEN EXPECTED TO WASH OUT LATE TUES INTO WED AS AN AREA OF LOW PRESSURE DEVELOPS OVER THE PLAINS STATES.

MODELS SHOW MORE UNCERTAINTY WITH THE EVOLN OF THE STORM SYSTEM SLATED FOR WED AND THURS. TREND HAS BEEN FOR NORTHERN STREAM ENERGY TO DIVE MORE TO THE EAST OVER THE PLAINS STATES AND ALLOW THE SOUTHERN ENERGY TO DRAW MORE MOISTURE NORTH INTO NM THURS. THIS BRINGS US INTO THE NEXT PERIOD OF ENHANCED POPS WED OR THURS. UNDERCUT MET/MAV GUIDANCE SINCE UNCERTAINTY IS STILL HIGH WITH THIS SYSTEM. IF NORTHERN STREAM ENERGY PHASES WITH SOUTHERN STREAM WILL BE TALKING ABOUT ANOTHER SNOW STORM ACROSS NM HOWEVER IF NORTHERN STREAM CONTINUES TO TREND TO THE EAST WILL HAVE MORE RAIN/SNOW SHOWER ACTIVITY. IN ANY EVENT...MODELS SHOW UNSETTLED PATTERN WILL CONTINUE INTO THE WEEKEND STATEWIDE.

&&

.PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 46 22 44 23 / 0 0 0 5 GALLUP.......................... 43 15 41 19 / 0 0 0 5 GRANTS.......................... 46 14 44 19 / 0 0 0 10 GLENWOOD........................ 55 29 53 31 / 0 0 0 0 CHAMA........................... 39 0 35 7 / 5 0 0 20 LOS ALAMOS...................... 41 14 39 13 / 5 0 0 20 RED RIVER....................... 35 5 32 9 / 5 0 0 20 TAOS............................ 40 9 39 12 / 5 0 0 20 SANTA FE........................ 41 19 40 21 / 0 0 0 20 SANTA FE AIRPORT................ 41 20 38 22 / 0 0 0 20 ESPANOLA........................ 46 19 44 21 / 0 0 0 20 ALBUQUERQUE HEIGHTS............. 48 26 46 29 / 0 0 0 5 ALBUQUERQUE VALLEY.............. 50 22 48 28 / 0 0 0 10 ALBUQUERQUE FOOTHILLS........... 45 25 44 28 / 0 0 0 10 ALBUQUERQUE WEST MESA........... 47 25 47 29 / 0 0 0 10 SOCORRO......................... 52 27 51 28 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 40 20 41 22 / 0 0 0 20 MORIARTY/ESTANCIA............... 43 22 43 24 / 0 0 0 20 CARRIZOZO....................... 49 23 50 28 / 0 0 0 5 RUIDOSO......................... 46 25 45 24 / 0 0 0 10 RATON........................... 40 13 39 16 / 0 0 0 20 LAS VEGAS....................... 40 18 40 19 / 0 0 0 20 ROY............................. 42 24 39 17 / 0 0 0 20 CLAYTON......................... 40 23 36 16 / 0 0 0 20 SANTA ROSA...................... 46 27 44 25 / 0 0 0 20 TUCUMCARI....................... 44 24 41 25 / 0 0 0 20 FORT SUMNER..................... 46 24 45 24 / 0 0 0 20 CLOVIS.......................... 43 26 43 25 / 0 0 0 20 PORTALES........................ 46 25 45 24 / 5 0 0 20 ROSWELL......................... 48 27 50 29 / 5 0 0 10

&&

.ABQ WATCHES/WARNINGS/ADVISORIES... NONE.

&&

$$

GUYER