National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KGRR 261607
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1207 PM EDT SAT JUL 26 2014

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 324 AM EDT SAT JUL 26 2014

THERE`S A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS TODAY, BUT A
BETTER CHANCE SUNDAY. WE/LL SEE A LITTLE SUNSHINE TODAY ALONG WITH
SOME CLOUDS. IT WILL BE NOTICEABLY MORE HUMID TODAY AS SOUTH WINDS
PUSH MORE MOISTURE NORTHWARD. AFTER SUNDAY`S STORMS...SOME OF WHICH
MAY BE STRONG...COOLER WEATHER WILL DEVELOP MONDAY. TEMPERATURES
WILL STRUGGLE TO REACH 70 MONDAY...SO DEFINITELY CHILLY FOR THE END
OF JULY. THE COOLER WEATHER WILL ONLY LAST A COUPLE OF DAYS BEFORE A
WARMING DEVELOPS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 324 AM EDT SAT JUL 26 2014

FORECAST CONCERNS DEAL WITH CONVECTIVE TRENDS THROUGH THE PERIOD.

OVERALL...AM NOT IMPRESSED WITH PCPN POTENTIAL TODAY. IT/S NOT
ZERO...BUT IT`S NOT REAL HIGH EITHER. A THUNDERSTORM HAS RECENTLY
DEVELOPED OVER NORTH CENTRAL WISCONSIN AND IS MOVING ESE. THIS IS
ASSOCIATED WITH A WEAK SHORT WAVE THAT WILL MOVE OVER NORTHERN
LOWER. WE`VE GONE WITH CHC POPS OVER THE NRN CWA AND SLIGHT CHC
ACROSS THE SOUTH. THEN DRY TONIGHT.

WV IMAGERY SHOWS A WRAPPED UP SHORT WAVE OVER WESTERN MANITOBA. THIS
LOW WILL DROP SOUTHEAST AND ACROSS THE CWA SUNDAY IN CONJUNCTION
WITH A SFC LOW. THIS SYSTEM HAS SOME STRONG DYNAMICS WITH IT. LI/S
NEAR -6C/SBCAPE NEAR 2500 J/KG /0-6KM BULK SHEAR 40-50KTS.
ORDINARILY...THIS WOULD BE A RECIPE FOR SEVERE STORMS. HOWEVER...THE
TRACK OF THE LOW DIRECTLY ACROSS THE CENTRAL CWA SUGGESTS THAT THE
STRONGEST STORMS MAY REMAIN JUST SOUTH OF THE CWA IN NORTHERN
INDIANA SUNDAY. THIS IS WHERE SLIGHT AND MODERATE RISKS ARE. THAT
SAID...A FEW STRONGER STORMS CERTAINLY WILL BE POSSIBLE ALONG/SOUTH
OF I-94.

AS THE LOW MOVES BY LATE SUNDAY...A SECONDARY COLD FRONT WILL DROP
SOUTH AND GENERATE A FEW SHOWERS. THESE SHOWERS WILL LINGER INTO
MONDAY AS COLDER AIR ALOFT MOVES OVER LOWER MICHIGAN AND STEEPER
LAPSE RATES DEVELOP. MONDAY WILL BE MUCH COOLER WITH HIGHS IN THE
UPPER 60S/LOWER 70S.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 324 AM EDT SAT JUL 26 2014

LONG TERM PERIOD IS DOMINATED BY UPPER TROUGHING THAT IS IN PLACE
ALMOST THE ENTIRE TIME FRAME. THE TROUGH IS AT ITS DEEPEST IN THE
FIRST COUPLE FORECAST PERIODS...MONDAY NIGHT AND TUESDAY WITH
HEIGHTS RISING A BIT EACH DAY THROUGH THE REMAINDER OF THE WEEK.

WE ARE LOOKING AT DIURNALLY DRIVEN SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS IN AND AROUND PEAK HEATING IN THE AFTERNOON AND EARLY
EVENING. THERE IS NOT MUCH IN THE WAY OF SURFACE FEATURES TO KEY
ON...SO WITH THE UPPER JET SOUTH OF THE GREAT LAKES THE COOL MID
LEVEL/JULY HEATING REGIME SHOULD RESULT IN DAILY SHOWERS/STORMS.

IN REGARD TO TEMPERATURES...THE START OF THE WEEK WILL BE
COOL...WITH GRADUALLY WARMING TEMPERATURES. NORMAL HIGHS ARE IN THE
LOWER 80S THIS TIME OF YEAR. HIGHS SHOULD WARM EACH DAY FROM THE LOW
70S ON TUESDAY TO AROUND 80 BY WEEKS END.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 754 AM EDT SAT JUL 26 2014

VFR CLOUD BASES ARE EXPECTED TODAY IN THE 3500-5000FT RANGE.
SCATTERED SHOWERS THIS MORNING SHOULD PUSH EAST AND NOT AFFECT THE
TAF SITES THIS MORNING. THERE IS A CHANCE FOR A STRAY SHOWER OR
ISOLATED THUNDERSTORM THROUGH THE COURSE OF THE DAY...BUT
CONFIDENCE IS LOW ENOUGH TO EXCLUDE FROM THE FORECAST AT THIS
POINT. EXPECTING MAINLY DRY CONDITIONS TODAY AT THE TAF SITES.

TONIGHT...WIDESPREAD THUNDERSTORMS ARE LIKELY SOUTH OF THE
STATE OF MICHIGAN...WITH MAINLY DRY CONDITIONS EXPECTED TO
CONTINUE OVER THE TAF SITES. MODELS ARE HINTING AT LOWER CLOUDS
SPREADING IN TONIGHT WITH IFR POSSIBLE IF NOT LOWER. AT THIS
POINT HAVE INTRODUCED MVFR VISIBILITIES AND SCATTERED CEILINGS AT
1500FT. LATER FORECASTS MAY NEED TO GO LOWER ON BOTH CEILINGS AND
VISIBILITIES AS CONFIDENCE IN THE FOG/STRATUS INCREASES.


&&

.MARINE...
ISSUED AT 324 AM EDT SAT JUL 26 2014

SOUTHWEST WINDS 5 TO 15 KNOTS WILL RESULT IN 1 TO 2 FOOT WAVES
TODAY. STRONGER WINDS AND CONSEQUENTLY HIGHER WAVES ARE EXPECTED
SUNDAY NIGHT INTO MONDAY AS A PUSH OF COLDER AIR FLOWS DOWN THE
LAKE. A SCA WILL PROBABLY BE NEEDED DURING THAT TIME FRAME.


&&

.HYDROLOGY...
ISSUED AT 1207 PM EDT SAT JUL 26 2014

THE MAIN PRECIPITATION THREAT WILL BE SUNDAY AS MOISTURE EDGES UP
INTO THE AREA. PWAT VALUES PUSH BETWEEN 1.0 TO 1.5 INCHES DURING
THE AFTERNOON. THIS MAY RESULT IN LOCALIZED HEAVY RAINFALL IN AND
AROUND THUNDERSTORMS. HOWEVER...AREA AVERAGES ARE MORE LIKELY TO
RANGE FROM ONE-QUARTER TO ONE-HALF AN INCH. PRECIPITATION THEN
SEEMS TO LINGER INTO MONDAY BUT SHOULD NOT BE OF ANY GREAT
SIGNIFICANCE IN THE MONDAY MORNING TIME FRAME.

ASIDE FROM SUNDAYS FOCUS...WE WILL SEE MAINLY DRY CONDITIONS TODAY.
ADDITIONAL CHANCES FOR LIGHT RAIN EXIST AS WE HEAD THROUGH THE NEW
WORK WEEK. NO HIGH END PRECIPITATION EVENTS ARE ANTICIPATED TO AFFECT
THE AREA. RIVERS CONTINUE TO RUN WELL BELOW ACTION STAGE...SO NO
CONCERN FOR RIVER FLOODING AT THIS TIME.



&&

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

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...JAM
MARINE...93