Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231612
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1112 AM EST MON FEB 23 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 330 AM EST MON FEB 23 2015

COLD WEATHER WILL CONTINUE THROUGH THE WEEK. HIGH PRESSURE WILL
BRING FAIR WEATHER TODAY THROUGH MOST OF TONIGHT. THE NEXT LOW
PRESSURE SYSTEM AND ARCTIC COLD FRONT WILL BRING SNOW TUESDAY
ALONG WITH GUSTY WINDS. ANOTHER REINFORCING SURGE OF ARCTIC AIR
WILL MOVE IN BEHIND THAT SYSTEM FOR MID TO LATE WEEK.

&&

.UPDATE...
ISSUED AT 1108 AM EST MON FEB 23 2015

WE DROPPED THE WIND CHILL ADVISORY EARLY AS VALUES ARE NO LONGER
COLDER THAN 15 BELOW ZERO.

FOCUSING NOW ON TOMORROWS SYSTEM. WE ARE CONSIDERING AN ADVISORY
FOR THE ENTIRE AREA...MAINLY FOR BLOWING AND DRIFTING SNOW. PLUS
ACCUMULATIONS LOOK LIKELY FOR PARTS OF THE REGION. FOR NOW WE ARE
WORKING ON AN IMPACT GRAPHIC THAT WILL LIKELY BE ISSUED CLOSER TO
1130 AM. LATER WE WILL DECIDE ON THE ISSUANCE OF AN ADVISORY.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EST MON FEB 23 2015

LOW PRESSURE AND AN ARCTIC COLD FRONT WILL BRING SNOW AND WINDY
CONDITIONS FOR TUESDAY. THE MOST SIGNIFICANT SNOW ACCUMULATIONS ON
THE ORDER OF 3 TO 5 INCHES ARE ANTICIPATED TO THE NW OF KGRR...
ROUGHLY ALONG AND NW OF A LINE FROM KMKG TO KRQB DUE TO LAKE
ENHANCEMENT. SE OF THAT LINE ONLY AROUND AN INCH OR TWO OF SNOW IS
ANTICIPATED.

IT IS NOTED THAT OVERALL SHORT RANGE GUIDANCE TRENDS
INDICATE THIS SYSTEM WILL MOVE IN A LITTLE SLOWER SUCH THAT THE
EARLY MORNING COMMUTE TUESDAY SHOULD NOT BE AFFECTED ACROSS MOST
OF OUR FCST AREA. HOWEVER THE COMBINATION OF THE SNOW AND BRISK SW
TO WEST WINDS WILL RESULT IN DEVELOPMENT OF SOME HAZARDOUS TRAVEL
CONDITIONS LATER TUESDAY MORNING THROUGH TUESDAY AFTERNOON INTO
THE EVENING PARTICULARLY NW OF KGRR.

LIGHTER SNOW SHOWERS WILL LINGER BEHIND THAT SYSTEM FOR TUESDAY
NIGHT INTO WEDNESDAY WITH LIGHT ADDITIONAL SNOW ACCUMULATIONS. MAX
TEMPS WEDNESDAY WILL STRUGGLE TO REACH THE UPPER SINGLE DIGITS TO
TEENS.

HIGH PRESSURE WILL PRODUCE FAIR BUT COLD WX TODAY WITH MAX TEMPS
ONLY REACHING THE UPPER SINGLE DIGITS TO LOWER TEENS AFTER A VERY
COLD START TO THE DAY. THE WIND CHILL ADVISORY REMAINS IN EFFECT
FOR OUR ENTIRE FCST AREA UNTIL NOON TODAY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EST MON FEB 23 2015

AN UPPER AIR PATTERN CHANGE COULD BRING SOME INTERESTING WEATHER
NEXT WEEKEND. UNTIL THAT TIME THOUGH...IT WILL BE MORE OF THE
SAME...ESPECIALLY IN REGARD TO THE COLD.

THE LONG TERM PERIOD BEGINS WEDNESDAY NIGHT WITH A SIMILAR UPPER AIR
PATTERN THAT WE HAVE SEEN MUCH OF THE WINTER WITH A CONTINUED DEEP
TROUGH OVER THE EASTERN UNITED STATES AND A UPPER RIDGE JUST OFF THE
WEST COAST. COLD AIR IS FIRMLY ENTRENCHED ACROSS THE GREAT LAKES.
AS WE MOVE INTO NEXT WEEKEND THE UPPER TROUGH RETROGRADES TO THE
WEST WITH TROUGHING INTO THE DESERT SOUTHWEST. A DEEP SOUTHWEST FLOW
IS IN PLACE BY SUNDAY FROM THE SOUTHERN PLAINS TO THE GREAT LAKES.

REGARDING THE SENSIBLE WEATHER HIGHLIGHTS...THE SECOND HALF OF THE
WORK WEEK WILL FEATURE COLD SURFACE HIGH PRESSURE SLOWING DRIFTING
THROUGH THE GREAT LAKES. WE EXPECT SOME LIGHT LAKE EFFECT SNOW
SHOWERS TOWARDS LAKE MICHIGAN...BUT THE SNOW GROWTH REGION IS
SHALLOW AS IS THE MOISTURE DEPTH. SO...LIMITED ACCUMULATIONS AT BEST
IN THE LAKE SHORE COUNTIES (MAINLY NORTH FLOW) FROM WEDNESDAY NIGHT
INTO FRIDAY. WEDNESDAY MORNING LOOKS TO BE ANOTHER COLD ONE WITH
LOWS BELOW ZERO OVER MUCH OF THE AREA.

MOST SIGNIFICANT WEATHER OF THE LONG TERM LOOKS TO COME SATURDAY
NIGHT THROUGH SUNDAY NIGHT AS A FRONTAL BOUNDARY SETS UP FROM THE
SOUTHERN PLAINS STATES TO THE SOUTHERN GREAT LAKES. OVERRUNNING
PRECIPITATION IS GENERATED FROM BOTH THE GFS AND THE ECMWF. THE
ECMWF IS WARMER AND WOULD IMPLY EVEN A MIX POSSIBLE ACROSS THE I94
COUNTIES. WAY TOO EARLY TO MAKE ANY DEFINITIVE STATEMENTS ABOUT THIS
TIME FRAME YET AS THE FORECAST SEEMS TO HINGE ON A SHORTWAVE
EJECTING OUT OF THE SOUTHWEST U.S. TROUGH AND RIDING ALONG THE
BOUNDARY. THE GFS HAS VERY LITTLE SURFACE REFLECTION WHILE THE ECMWF
HAS A WEAK LOW. BOTTOM LINE...SOME ACCUMULATING SNOW A POSSIBILITY
LATE SATURDAY NIGHT THROUGH SUNDAY AND INTO SUNDAY NIGHT. IF THE
ECMWF VERIFIES A POSSIBLE MIX AS WELL IN THE SOUTH TOWARDS I94.
PLENTY OF TIME TO EVALUATE THIS SYSTEM THOUGH AND WATCH MODEL
TRENDS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 652 AM EST MON FEB 23 2015

MVFR CEILINGS ARE LOCATED NEAR LAKE MICHIGAN THIS MORNING...AT
KMKG...WITH CLEAR SKIES INLAND. AS WINDS TURN WESTERLY IN THE
CLOUD LAYER TODAY THESE CLOUDS WILL BE PUSHED INLAND THROUGH ALL
OF THE TAF SITES. BY 18Z...ALL SITES SHOULD SEE MVFR CEILINGS
SPREAD IN. LAKE EFFECT SNOW OCCURRING NEAR THE LAKE MICHIGAN SHORE
THIS MORNING WILL DRIFT INLAND THROUGH THE COURSE OF THE DAY...BUT
NOT EXPECTING MUCH MORE THAN FLURRIES.

SKIES WILL TRY TO CLEAR OUT TONIGHT AS WINDS TURN SOUTHWEST. KMKG
MAY HOLD ON TO THE CLOUDS...BUT TOOK CEILINGS VFR THERE AFTER 00Z.

THE MAIN STORY OVERNIGHT WILL BE AN INCREASE IN THE WIND FROM THE
SOUTHWEST. SUSTAINED WINDS OF 10-20 KNOTS SHOULD BE COMMON BY
DAYBREAK TUESDAY WITH GUSTS IN THE 20-30 KNOT RANGE.


&&

.HYDROLOGY...
ISSUED AT 258 PM EST SUN FEB 22 2015

WITH NO MAJOR WARM UPS OR RAINFALL HEADED OUR WAY IN THE NEAR
FUTURE...RUNOFF WILL BE LIMITED. SERIOUS ICE JAMS AND FLOODING
CONCERNS ARE UNLIKELY UNTIL A SIGNIFICANT WARM UP AND RAINFALL
OCCUR.  CONSIDERABLE ICE DOES EXIST IN THE RIVERS SO WE WILL NEED
TO MONITOR TRENDS CLOSELY. FOR NOW WITH CONDITIONS STABLE DUE TO
THE ARCTIC AIRMASS IN PLACE...THE RISK IS SOMEWHAT LIMITED FOR
FLOODING.

&&

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

$$

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






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