000
FXUS63 KGRR 040445
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1145 PM EST TUE MAR 3 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 325 PM EST TUE MAR 3 2015

FREEZING DRIZZLE WILL CONTINUE INTO THE EVENING HOURS...SO SLIPPERY
ROADS WILL REMAIN A CONCERN TONIGHT...ESPECIALLY THE SECONDARY
ROADS. PRECIPITATION SHOULD TAPER OFF OVERNIGHT BEHIND A COLD FRONT
WITH TEMPERATURES FALLING THROUGH THE 20S. ARCTIC AIR SURGES BACK
INTO THE REGION FOR WEDNESDAY AND THURSDAY WITH HIGHS ONLY IN THE
TEENS ON THURSDAY. THIS ARCTIC COLD SNAP WILL BE FAIRLY SHORT LIVED
WITH TEMPERATURES REBOUNDING BACK TO NORMAL VALUES IN THE 30S OVER
THE WEEKEND. SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE EXPECTED ACROSS
WESTERN LOWER MICHIGAN WEDNESDAY THROUGH THURSDAY...BUT WITH A
DRY...COLD AIRMASS IN PLACE ANY ACCUMULATIONS WILL BE LIGHT.

&&

.UPDATE...
ISSUED AT 634 PM EST TUE MAR 3 2015

DECIDED TO DROP THE WINTER WEATHER ADVISORY JUST A BIT EARLY AS KGRR
RADAR TRENDS THE PAST COUPLE OF HOURS SHOW LINGERING LIGHT PCPN
WAS ENDING ACROSS OUR FORECAST AREA. THIS AS BRISK WEST WINDS
ADVECT DRIER AIR INTO THE LOWER LEVELS OF THE ATMOSPHERE. BRISK
WEST WINDS WILL CONTINUE THROUGH THE EVENING BEFORE GRADUALLY
SUBSIDING LATE TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM EST TUE MAR 3 2015

WILL KEEP THE WINTER WEATHER ADVISORY IN PLACE THROUGH 800PM. WE ARE
STILL GETTING REPORTS OF UNKNOWN PRECIP ACROSS CENTRAL LOWER
MICHIGAN AND LIGHT FREEZING RAIN AND FREEZING DRIZZLE OVER A GOOD
DEAL OF THE REMAINDER OF THE FORECAST AREA. CURRENT KGRR
REFLECTIVITY SHOWS VERY LIGHT RETURNS...WHICH ARE CONSISTENT WITH
FREEZING DRIZZLE TYPICALLY. BUFKIT OVERVIEWS SHOW SOME WEAK LIFT IN
THE SHALLOW MOISTURE WITH THE DGZ UNSATURATED. THIS SETUP CONTINUES
INTO THE EVENING HOURS AT LEAST. SO...WITH ONGOING FREEZING PRECIP
AND MODEL DATA INDICATING IT WILL CONTINUE INTO THE EVENING IF NOT
THE OVERNIGHT...LEAVING THE WINTER WEATHER ADVISORY STAND. WE WILL
BE MONITORING OBS AND NEW MODEL DATA THE REMAINDER OF THE EVENING
AND DETERMINE WHETHER TO DROP OR EXTEND THE WWA AS WE APPROACH
800PM. NEED TO KEEP IT ROLLING THROUGH THE EVENING COMMUTE FOR SURE.

BEYOND THIS EVENING IMPACT WEATHER CONCERNS ARE MINIMAL OUTSIDE OF
THE COLD. VERY SHALLOW MOISTURE WILL BE IN PLACE FROM WEDNESDAY INTO
THURSDAY NIGHT...BUT IT IS BELOW 4000FT FOR THE MOST PART. THESE
SHALLOW MOISTURE DEPTHS COMBINED WITH A VERY SHALLOW DGZ SHOULD
RESULT IN SMALL FLAKE SIZE AND LIMITED ACCUMULATIONS TOWARDS THE
LAKE. IN FACT HAVE ONLY CHANCE PROBABILITY OF PRECIPITATION
PERCENTAGES IN THE FORECAST IN THE WEST (30-50 PCT).

COLDEST AIR IS SITUATED OVER THE AREA WEDNESDAY NIGHT AND THURSDAY.
IN AREAS RECEIVING THE VERY FINE/SMALL SNOWFLAKES SOME TRAVEL
INCONVENIENCES MAY OCCUR DUE TO THE COLD AIR TEMPS AND SNOW ON THE
ROADS. WE HAVE SEEN THIS SCENARIO MULTIPLE TIMES THIS WINTER. JUST
NOT EXPECTING MUCH IN THE WAY OF SNOW FOR BIG IMPACTS. LOWS
WEDNESDAY NIGHT WILL BE BELOW ZERO NORTHEAST OF GRAND RAPIDS TOWARDS
MT. PLEASANT AND ONLY STRUGGLE INTO THE TEENS ON THURSDAY EVERYWHERE.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 325 PM EST TUE MAR 3 2015

FAIRLY TRANQUIL WEATHER IS ANTICIPATED THROUGH THE LONG RANGE
FORECAST PERIOD. SW FLOW AND SOME SUN WILL HELP TO BOOST MAX TEMPS
INTO THE 20S FOR FRIDAY AFTER A VERY COLD START TO THE DAY.
TEMPERATURES WILL MODERATE SOMEWHAT FOR THE WEEKEND REACHING THE 30S
AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL.

A COUPLE OF WEAK SYSTEMS APPROACHING FROM THE NW MAY BRING A FEW
LIGHT SNOW SHOWERS SATURDAY AND SUNDAY NIGHT INTO MONDAY BUT WITH
VERY LITTLE TO NO SNOW ACCUMULATIONS ANTICIPATED.

TEMPERATURES WILL CONTINUE TO UNDERGO A GRADUAL MODERATING TREND
NEXT WEEK. BEYOND TUESDAY THERE ARE STRONG SIGNALS IN A
CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE THAT AN UPPER LEVEL RIDGE
WILL AMPLIFY AND BUILD IN FROM THE WEST. THIS PATTERN FAVORS
POTENTIAL FOR MUCH ABOVE NORMAL TEMPERATURES BY MID TO LATE NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1138 PM EST TUE MAR 3 2015

COLDER AIR WILL BE ARRIVING FROM THE NORTHWEST...EVENTUALLY
SUPPORTING LAKE EFFECT CLOUDS AND EVEN SOME SNOW SHOWERS. I DID
ADD VCSH TO THE TAFS PRIMARILY AFTER 15Z WED. AT THIS TIME ANY
IMPACT CONDITIONS FROM THE SNOW SHOWERS SHOULD BE VERY LOCALIZED
AND BRIEF.

MVFR CLOUDS STILL PREVAIL AND SHOULD CONTINUE THROUGH MUCH OF THE
NIGHT. KLDM DID GO TO VFR RECENTLY AND KFKS HAS CLEARED OUT. I
WILL MAINTAIN THE TREND OF VFR WEATHER ARRIVING WED AM DESPITE
POSSIBLE SNOW SHOWERS.

&&

.HYDROLOGY...
ISSUED AT 325 PM EST TUE MAR 3 2015

GENERALLY A QUARTER TO HALF INCH OF LIQUID EQUIVALENT HAS BEEN ADDED
TO THE SNOWPACK TODAY FROM A COMBINATION OF SNOW...SLEET...AND
FREEZING RAIN. THE HEAVIEST PCPN HAS MOVED OFF TO THE EAST AS OF
THIS WRITING...LEAVING ONLY LIGHT DZ OR FZDZ.

SNOW WATER EQUIVALENT VALUES ARE ESTIMATED TO BE AROUND AN INCH NEAR
THE HEADWATERS OF THE GRAND RIVER IN JACKSON COUNTY. SWE VALUES
INCREASE TO AROUND 2 INCHES IN LANSING AND GRAND RAPIDS. SWE VALUES
OF 3+ INCHES ARE POSSIBLE IN OTTAWA COUNTY. SIMILAR STORY ALONG THE
MUSKEGON RIVER WITH SWE VALUES AROUND 2 INCHES IN BIG RAPIDS
INCREASING TO 3-4 INCHES CLOSER TO THE LAKESHORE. A BIG WARM UP IN
ADDITION TO A 1-3 INCH RAINFALL EVENT...FOR EXAMPLE...WOULD
CERTAINLY MEAN FLOODING CONCERNS.

WITH VERY COLD TEMPERATURES IN PLACE TONIGHT THROUGH FRIDAY...NO
SIGNIFICANT ICE BREAKUP IS EXPECTED. ICE JAM POTENTIAL IS FAIRLY
LOW. THE LATEST MODELS ARE INDICATING A WARMING TREND THIS WEEKEND
AND ESPECIALLY INTO NEXT WEEK. HIGHS GENERALLY IN THE MID 30S ARE
EXPECTED THIS WEEKEND INCREASING TO THE UPPER 30S TO AROUND 40
DEGREES EARLY NEXT WEEK. THE NORTH CENTRAL RIVER FORECAST CENTER
INDICATES THERE IS A MEDIUM RISK FOR A BREAK-UP ICE JAM FOR THE
GRAND RIVER NEAR ROBINSON TOWNSHIP. A BREAK-UP ICE JAM IS LIKELY
THIS MONTH...BUT NOT IN THE NEXT 7 DAYS.

HOWEVER...ACCORDING TO THE CLIMATE PREDICTION CENTER...THERE IS A 40
PERCENT CHANCE FOR ABOVE NORMAL TEMPERATURES MARCH 10-16. HIGHS IN
THE 40S AND 50S SEEM ATTAINABLE NEXT WEDNESDAY AND THURSDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...LAURENS
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...EBW