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Thread: some hope
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12-05-2008, 09:29 PM #1
some hope
official sounding bs:
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS, MD
300 PM EST FRI DEC 05 2008
6-10 DAY OUTLOOK FOR DEC 11 - 15 2008
THE MODEL SOLUTIONS ARE IN FAIR AGREEMENT ON THE EXPECTED 500-HPA HEIGHT
PATTERN DEPICTING A POTENTIAL LONGWAVE PATTERN CHANGE. FOR THE SECOND
CONSECUTIVE DAY, MODEL GUIDANCE INDICATES THAT A SIGNIFICANT INCREASE IN
500-HPA HEIGHTS OVER THE ALEUTIANS SHOULD RESULT IN THE AMPLIFICATION OF A
TROUGH DOWNSTREAM ACROSS THE WESTERN THIRD OF THE CONUS. MEANWHILE, THE RIDGE
OVER THE NORTH ATLANTIC WILL FAVOR THE PERSISTENCE OF A WEAK TO MODERATE TROUGH
ACROSS THE EASTERN CONUS. THE TIMING OF THIS POTENTIAL LONGWAVE PATTERN CHANGE
IS CRITICAL TO THE TEMPERATURE OUTLOOK. AT THE BEGINNING OF THE PERIOD, BELOW
NORMAL TEMPERATURES SHOULD PREVAIL ACROSS THE SOUTHEAST. HOWEVER, A MODERATING
TEMPERATURE TREND LATER IN THE PERIOD SHOULD RESULT IN NEAR NORMAL TEMPERATURES
FOR THE 5-DAY PERIOD. FOR THE REMAINDER OF THE CONUS, BELOW NORMAL TEMPERATURES
SHOULD DOMINATE. BELOW NORMAL TEMPERATURES ARE FORECAST FOR THE ALASKAN
PANHANDLE AND SOUTHEAST ALASKA WITH NEAR OR ABOVE NORMAL TEMPERATURES ACROSS
THE REMAINDER OF THE STATE. REGARDING THE PRECIPITATION OUTLOOK ACROSS THE
CONUS, MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING A LOW PRESSURE SYSTEM
DEPARTING THE EAST COAST AT THE BEGINNING OF THE PERIOD. AS THE LONGWAVE TROUGH
RETROGRADES, THE STORM TRACK SHOULD SHIFT WEST. ABOVE NORMAL PRECIPITATION IS
FORECAST FROM THE MIDDLE MISSISSIPPI VALLEY AND OHIO VALLEY INTO THE
MID-ATLANTIC, NORTHEAST, AND NEW ENGLAND WITH BELOW NORMAL PRECIPITATION
EXPECTED ACROSS FLORIDA. WITH A DEEPENING TROUGH ACROSS THE WESTERN CONUS,
ABOVE NORMAL PRECIPITATION CAN BE EXPECTED ACROSS THE ROCKIES AND SOUTHWEST.
DOWNSTREAM OF THE RIDGE AXIS CENTERED OVER THE ALEUTIANS, BELOW NORMAL
PRECIPITATION IS FORECAST IN SOUTHEAST ALASKA, THE ALASKAN PANHANDLE, PACIFIC
NORTHWEST, AND NORTHERN CALIFORNIA.
TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 20 PERCENT OF TODAY'S OPERATIONAL
ECMWF CENTERED ON DAY 7...20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...AND
40 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8.
MODEL OF THE DAY: GFS SUPERENSEMBLE MEAN.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 ON A SCALE OF 1 TO 5,
DUE TO FAIR AGREEMENT AMONG THE MODEL SOLUTIONS AND UNCERTAINTY IN THE TIMING
OF A POTENTIAL LONGWAVE PATTERN CHANGE.
THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTOMATED TEMPERATURE
FORECAST, KLEIN AND ANALOG TEMPERATURE SPECIFICATIONS FROM THE BLENDED HEIGHT
FIELD, KLEIN AND ANALOG TEMPERATURE SPECIFICATIONS FROM THE GFS ENSEMBLE MEANS,
AND TELECONNECTIONS ON A POSITIVE 500-HPA HEIGHT ANOMALY CENTER AT 60N 165W.
THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE CPC AUTOMATED PRECIPITATION
FORECAST, ANALOG PRECIPITATION SPECIFICATIONS FROM THE BLENDED HEIGHT FIELD,
THE NAEFS PRECIPITATION FORECAST, CALIBRATED PRECIPITATION AMOUNTS FROM THE GFS-BASED MODELS, TELECONNECTIONS ON A POSITIVE 500-HPA HEIGHT ANOMALY CENTER
AT 60N 165W, AND INSPECTION OF DAILY PRECIPITATION FORECASTS FROM THE VARIOUS
MODELS.
8-14 DAY OUTLOOK FOR DEC 13 - 19 2008
FOR THE WEEK 2 PERIOD MODEL SOLUTIONS ARE IN BETTER AGREEMENT COMPARED TO THE
DAY 6-10 PERIOD AFTER THE EXPECTED LONGWAVE PATTERN CHANGE OCCURS. A LONGWAVE
TROUGH BECOMES ESTABLISHED ACROSS THE WESTERN CONUS, WHILE A WEAK RIDGE
DEVELOPS ACROSS THE SOUTHEASTERN CONUS. THE DEVELOPMENT OF A LONGWAVE TROUGH
ACROSS THE WESTERN CONUS RESULTS FROM A STRENGTHENING RIDGE OVER THE ALEUTIANS.
TELECONNECTIONS ON A LARGE POSITIVE 500-HPA HEIGHT ANOMALY CENTER OVER THE
ALEUTIANS SUPPORT THE AFOREMENTIONED TROUGH/RIDGE PATTERN. THE OFFICIAL BLENDED
HEIGHT CHART SHOWS A POSITIVELY TILTED TROUGH EXTENDING FROM HUDSON BAY
SOUTHWEST INTO THE DESERT SOUTHWEST, A RIDGE OVER THE ALEUTIANS, AND A RIDGE IN
THE NORTH ATLANTIC. THIS EXPECTED LONGWAVE PATTERN YIELDS BELOW NORMAL
TEMPERATURES ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS WITH ABOVE NORMAL
TEMPERATURES ACROSS THE SOUTHEASTERN CONUS. THE PRESENCE OF THE RIDGE IN THE
NORTH ATLANTIC MAY SLOW THE MODERATION OF TEMPERATURES ACROSS THE NORTHEAST AND
NEW ENGLAND. AS THE WESTERN CONUS TROUGH BECOMES DEEPER, A TREND TOWARDS WETTER
CONDITIONS IS EXPECTED IN CALIFORNIA WHILE ABOVE NORMAL PRECIPITATION SHOULD
CONTINUE ACROSS THE ROCKIES AND SOUTHWEST. DOWNSTREAM OF THE WESTERN CONUS
TROUGH, ABOVE NORMAL PRECIPITATION IS FORECAST FROM THE OHIO VALLEY INTO THE
NORTHEAST AND NEW ENGLAND. A WEAK RIDGE SHOULD RESULT IN BELOW NORMAL
PRECIPITATION ALONG THE GULF COAST AND FLORIDA. ACROSS MUCH OF ALASKA, BELOW
NORMAL TEMPERATURES AND PRECIPITATION CAN BE EXPECTED.
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 10 PERCENT OF TODAY'S OPERATIONAL
0Z GFS CENTERED ON DAY 11...10 PERCENT OF TODAY'S OPERATIONAL 6Z GFS CENTERED
ON DAY 11...30 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20
PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...AND 30 PERCENT OF
TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 ON A SCALE OF
1 TO 5, DUE TO GOOD AGREEMENT AMONG THE GFS ENSEMBLE MEAN SOLUTIONS,
TEMPERATURE TOOLS, AND PRECIPITATION TOOLS.Last edited by Sol Skier; 12-06-2008 at 08:40 AM. Reason: ease
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