Small Craft Advisory 19, NWS Milwaukee, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
338 AM CST SAT FEB 28 2009

FORECAST FOCUS ON LINGERING VERY LIGHT SNOW/FLURRIES THIS
MORNING...GENERALLY QUIET AND COOL WEATHER INTO NEXT WEEK.

LATEST WATER VAPOR IMAGERY INDICATED SPLIT UPPER LEVEL FLOW OVER
NORTH AMERICA. NORTHERN STREAM WAS LOCATED FROM CENTRAL CANADA TO
A TROUGH IN THE NORTHEASTERN USA. SOUTHERN STREAM WAS LOCATED FROM
A RIDGE IN THE WESTERN STATES...TO AROUND THE SOUTH END OF A
SHORTWAVE TROUGH IN THE CENTRAL PLAINS...INTO THE SOUTHEASTERN
STATES. FORECAST AREA GENERALLY BETWEEN THESE TWO STREAMS.

AT THE SURFACE...HIGH PRESSURE WAS LOCATED OVER SOUTH CENTRAL
SOUTH DAKOTA...WITH LOW PRESSURE WELL SOUTH OF THE REGION.

.TODAY...PESKY VERY LIGHT SNOW AND FLURRIES CONTINUING ACROSS
MAINLY THE EASTERN HALF OF THE FORECAST AREA. LATEST RUC SOUNDINGS
AT MILWAUKEE INDICATED THE MOIST LAYER BELOW 4000 FEET SHOULD
GRADUALLY MIX OUT THIS MORNING...AS DRIER AIRMASS WORKS INTO THE
AREA. LATEST HIGH RESOLUTION WRF MODEL WITH GFS BOUNDARY
CONDITIONS ALSO INDICATED ANY VERY LIGHT SNOW AND FLURRIES TO
DIMINISH.

SO...WILL KEEP CLOUDS WITH VERY LIGHT SNOW/FLURRIES IN FORECAST
THIS MORNING. CLOUDS SHOULD THEN SCATTER OUT THIS AFTERNOON. COLD
TEMPERATURES EXPECTED TODAY...AND WENT BELOW WARM GFS MOS GUIDANCE
VALUES.

.TONIGHT THROUGH MONDAY...SHOT OF COLD AIR ADVECTION MOVES INTO
THE AREA LATER TONIGHT...AHEAD OF APPROACHING SURFACE HIGH
PRESSURE. 1000/500MB THICKNESSES DROP FROM THE UPPER 520S DKM
RANGE AT 06Z SUNDAY...TO THE UPPER 510S DKM RANGE BY 18Z SUNDAY.
THIS SHOULD REINFORCE THE COLD AIRMASS OVER THE REGION. CONTINUED
TO GO BELOW GFS MOS GUIDANCE FOR TEMPERATURES IN THIS PERIOD.

ANOTHER CHANCE FOR VERY LIGHT SNOW OR FLURRIES LATER SUNDAY
AFTERNOON AND SUNDAY NIGHT...AS ONSHORE WINDS COMBINE WITH
FAVORABLE LOW LEVEL DELTA T VALUES OF AROUND 15 DEGREES CELSIUS.
GFS KEEPS FAVORABLE FETCH WITH FAIRLY BRISK WINDS THROUGH
MONDAY...WHILE THE NAM SHIFTS WINDS EAST TO SOUTHEAST SUNDAY
NIGHT...THEN WEAKENS THEM. GIVEN THIS UNCERTAINTY...WILL LEAVE
DRY FORECAST FOR NOW.

.MONDAY NIGHT THROUGH FRIDAY...ECMWF AND GFS IN FAIR AGREEMENT
THROUGH THURSDAY. APPROACHING UPPER LEVEL RIDGE AND SURFACE HIGH
MOVING THROUGH THE AREA SHOULD MAINTAIN THE DRY FORECAST THROUGH
MID WEEK. THE COLD TEMPERATURES SHOULD SLOWLY REBOUND BY LATER IN
THE WEEK...AS HIGH SHIFTS TO THE EAST...AND WEAK WARM AIR
ADVECTION ENSUES.

BOTH MODELS DEVELOP SURFACE LOW IN THE CENTRAL HIGH PLAINS LATE
THURSDAY...BUT TAKE THEM ON DIFFERENT PATHS THURSDAY NIGHT AND
FRIDAY. GIVEN THE UNCERTAINTY THIS FAR OUT...WILL LEAVE THE
FORECAST AS IS FOR LATE NEXT WEEK.

&&

.AVIATION...EXPECT OCNL LIGHT SNOW SHOWERS AND FLURRIES TO
CONTINUE THRU MID MORNING IN THE EAST. DIMINISHING 1000-850MB
BACKING WINDS WILL ALLOW SLIGHTLY DRIER AIR TO ENTRAIN INTO THE
CLOUD AREA HELPING TO DIMINISH THE LIGHT PRECIPITATION LATE THIS
MORNING AND EARLY AFTERNOON. WOULD EXPECT MVFR SC FIELD TO
GRADUALLY THIN AND DISSIPATE DURING THE AFTERNOON AND EVENING. WL
NEED TO WATCH FOR RETURNING SC WITH SURGE OF COLD AIR ADVECTION
LATE TNGT.

&&

.MARINE...GLERL ICE COVERAGE APPEARS TO BE HIGH BUT UNABLE TO
CONFIRM DUE TO LACK OF RECENT CLOUD FREE HI RES MODIS IMAGERY.
WIDESPREAD LIGHT SNOW SHOWERS OVERNIGHT IN FAVORABLE FETCH ALSO
INDICATOR OF LESS SIGNIFICANT ICING OFFSHORE. WL DROP ICE COVERAGE
TO LESS THAN 50 PERCENT AND WAIT FOR BETTER VSBLE IMAGERY TO BUMP
UP IF NECESSARY.

WL CANCEL SMALL CRAFT ADVISORY SEVERAL HOURS EARLY NORTH OF
NORTHPOINT LIGHT AS PRESSURE GRADIENT WEAKENS...BUT HANG ON IN THE
SOUTH UNTIL 15Z. SMALL CRAFT ADVISORY CONDITIONS LIKELY TO RETURN
LATE TONIGHT DUE TO STRONG LOW LEVEL COLD AIR ADVECTION.
STEEPENING LOW LEVEL LAPSE RATES AFTER 06Z TONIGHT WILL ALLOW WIND
GUSTS TO 25KTS TO REACH SURFACE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LMZ645-646.

&&

SHORT/LONG TERM...08/WOOD
AVIATION/MARINE...11/MBK

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>