000
FXUS06 KWBC 201954
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON MAY 20 2013
6-10 DAY OUTLOOK FOR MAY 26 - 30 2013
TODAY`S ENSEMBLE MEAN SOLUTIONS EXHIBIT GOOD AGREEMENT ON THE PREDICTED MEAN
500-HPA HEIGHTS FOR THE 6-10 DAY PERIOD OVER NORTH AMERICA. MOST SOLUTIONS
AGREE ON 500-HPA TROUGHS ALONG THE WEST COAST AND NORTHEAST OF THE LOWER 48
STATES, AND 500-HPA RIDGES OVER THE CENTRAL-EASTERN CONUS. THE GFS AND ECMWF
OPERATIONAL RUNS ARE IN FAIRLY GOOD AGREEMENT WITH THEIR RESPECTIVE ENSEMBLE
MEANS, ALTHOUGH THE OPERATIONAL SOLUTIONS ARE GENERALLY MORE AMPLIFIED WITH THE
MAIN CIRCULATION FEATURES. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE LOW TO
MODERATE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN. MORE WEIGHTING WAS
GIVEN TO THE 00Z ECMWF ENSEMBLE MEAN BASED ON ITS SKILL DURING THE PAST 60 DAYS
AND ON ANALOG ANOMALY CORRELATIONS, WHICH MEASURE HOW CLOSELY THE MODEL
FORECASTS RESEMBLE 500-HPA FLOW PATTERNS THAT HAVE OCCURRED IN THE HISTORICAL
RECORD.
TODAYS BLEND CHART INDICATES NEAR TO BELOW NORMAL HEIGHTS FOR THE WEST CONUS,
WITH NEAR TO ABOVE NORMAL HEIGHTS EXPECTED OVER MUCH OF THE CENTRAL AND EASTERN
CONUS.
ANOMALOUS UPPER-LEVEL TROUGHING LEADS TO ENHANCED CHANCES FOR BELOW NORMAL
TEMPERATURES OVER THE WEST COAST OF THE LOWER 48 STATES. THERE ARE INCREASED
ODDS OF ABOVE NORMAL TEMPERATURES OVER MOST OF THE CENTRAL AND EASTERN CONUS,
WHICH IS PRIMARILY ATTRIBUTED TO PREDICTED ABOVE-NORMAL 500-HPA HEIGHTS,
ACCOMPANYING RIDGES, WITH SOUTHERLY OR SOUTHWESTERLY ANOMALOUS FLOW. THE
RIDGING FORECAST AND ASSOCIATED POSITIVE 500-HPA HEIGHT ANOMALIES OVER ALASKA
LEAD TO ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR THIS AREA.
ANOMALOUS UPPER-LEVEL TROUGHING FAVORS ABOVE MEDIAN PRECIPITATION FROM PACIFIC
NORTHWEST EASTWARD THROUGH THE NORTHERN PLAINS TO THE GREAT LAKES. THERE ARE
ENHANCED ODDS FOR BELOW-MEDIAN PRECIPITATION ACROSS PARTS OF THE CENTRAL GREAT
BASIN, THE SOUTHWEST, THE CENTRAL AND SOUTHERN PLAINS, THE LOWER MISSISSIPPI
AND TENNESSEE VALLEY, THE SOUTHEAST AND ALASKA. THIS IS PRIMARILY ATTRIBUTED TO
ABOVE-NORMAL 500-HPA HEIGHTS AND ASSOCIATED MEAN RIDGES.
TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 10 PERCENT OF TODAY`S OPERATIONAL 0Z
GFS CENTERED ON DAY 8...10 PERCENT OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON
DAY 8...10 PERCENT OF TODAY`S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...10
PERCENT OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...10 PERCENT OF
TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...40 PERCENT OF TODAY`S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8...AND 10 PERCENT OF TODAY`S 0Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8.
MODEL OF THE DAY: TODAY`S 00Z ECMWF ENSEMBLE MEAN
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: NEAR-AVERAGE, 3 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT BUT OFFSET SOMEWHAT BY DISAGREEMENTS BETWEEN THE VARIOUS
SURFACE TOOLS.
8-14 DAY OUTLOOK FOR MAY 28 - JUN 03, 2013
TODAY`S ENSEMBLE MEAN SOLUTIONS EXHIBIT GOOD AGREEMENT ON THE EXPECTED MEAN
500-HPA CIRCULATION PATTERN OVER NORTH AMERICA AND VICINITY FOR THE 8-14
DAY PERIOD. THE MAIN CIRCULATION FEATURES DEPICTED BY THE ENSEMBLE MEANS
INCLUDE A 500-HPA HEIGHT RIDGE OVER THE CENTRAL-EASTERN CONUS AND TROUGHS OVER
THE WEST COAST AND THE NORTHEAST OF THE CONUS. THE GFS OPERATIONAL RUNS ARE IN
FAIRLY GOOD AGREEMENT WITH THEIR RESPECTIVE ENSEMBLE MEANS, ALTHOUGH THE
OPERATIONAL SOLUTIONS ARE GENERALLY MORE AMPLIFIED WITH THE MAIN CIRCULATION
FEATURES. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE LOW TO MODERATE SPREAD
ACROSS THE MAJORITY OF THE FORECAST DOMAIN.TODAY`S WEEK 2 UPPER-LEVEL HEIGHT
MANUAL BLEND FAVORS THE 00Z ECMWF ENSEMBLE MEAN SOLUTION.
THE PRECIPITATION AND TEMPERATURE PATTERNS IN THE WEEK 2 PERIOD IS EXPECTED TO
BE VERY SIMILAR TO THAT FROM THE 6-10 DAY PERIOD, ONLY LOWER PROBABILITIES.
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...10 PERCENT OF TODAY`S 0Z GFS ENSEMBLE MEAN CENTERED ON
DAY 11...10 PERCENT OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20
PERCENT OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...25 PERCENT OF
TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11...AND 15 PERCENT OF
TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO
FAIR AGREEMENT AMONG THE VARIOUS 500-HPA HEIGHT FORECASTS AND SURFACE TOOLS.
FORECASTER: LUKE HE
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.
THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS
THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "F"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "INCHES"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL
BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY
EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY
SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A
FORECAST OF LITTLE OR NO PRECIPITATION.
THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN
THE CLIMATE OUTLOOKS.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON
JUNE 20
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19620519 - 20010504 - 19990430 - 20070505 - 19850514
ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19990429 - 19620519 - 20070506 - 19620602 - 20010505
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 26 - 30 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B N
SRN CALIF B N IDAHO N A NEVADA B N
W MONTANA N A E MONTANA N A WYOMING N N
UTAH N B ARIZONA N B COLORADO A B
NEW MEXICO A B N DAKOTA N A S DAKOTA A A
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A B ALABAMA A B NEW YORK N N
VERMONT N N NEW HAMP N N MAINE N N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA A N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA N N GEORGIA N B
FL PNHDL N B FL PENIN N N AK N SLOPE A B
AK ALEUTIAN N N AK WESTERN A B AK INT BSN A B
AK S INT A B AK SO COAST A B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 28 - JUN 03, 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B A NRN CALIF B N
SRN CALIF N N IDAHO N A NEVADA N N
W MONTANA N A E MONTANA N A WYOMING N A
UTAH N N ARIZONA N B COLORADO A B
NEW MEXICO N B N DAKOTA N A S DAKOTA A A
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS N B W TEXAS A B
MINNESOTA N A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A B
FL PNHDL N B FL PENIN N N AK N SLOPE A B
AK ALEUTIAN N N AK WESTERN N B AK INT BSN A B
AK S INT A B AK SO COAST A B AK PNHDL A N
LEGEND
TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN
A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN
B - BELOW B - BELOW
THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.
FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.
$$
000
FXCA20 KWBC 201829
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
228 PM EDT MON MAY 20 2013
DISCUSSION FROM MAY 20/00UTC: AT MID/UPPER LEVELS...SHORT WAVE
RIDGE IS INITIALIZED OVER WESTERN PORTIONS OF THE DOMAIN...WITH
AXIS EXTENDING BETWEEN NORTHERN CENTRAL AMERICA/SOUTHERN MEXICO TO
THE WESTERN CARIBBEAN/SOUTHERN GULF OF MEXICO. AT 250 HPA THIS IS
TO GENERALLY HOLD OVER THE NEXT FEW DAYS...WHILE AT 500 HPA IT
TENDS TO ERODE ACROSS CENTRAL AMERICA WHILE GENERALLY HOLDING TRUE
ACROSS THE CENTRAL-SOUTHERN STATES OF MEXICO. ACROSS
CENTRAL-SOUTHERN MEXICO THIS IS TO CONTINUE INHIBITING ORGANIZED
DEEP CONVECTION...WITH LATE AFTERNOON CONVECTION TO GENERALLY
LIMIT TO CENTRAL PORTIONS OF MEXICO ALONG THE SIERRA MADRE WHERE
WE EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. THE
MOST ACTIVE IS EXPECTED ON DAYS 02-04. OVER NORTHERN CENTRAL
AMERICA... AS MID LEVEL RIDGE PATTERN ERODES...EXPECTING
CONVECTION ALONG THE CONTINENTAL DIVIDE TO CLUSTER OVER NORTHERN
EL SALVADOR/SOUTHERN GUATEMALA. IN THIS AREA INITIALLY EXPECT
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM/DAY. THROUGH
72-84 HRS THIS WILL INCREASE TO 05-10MM/DAY AND MAXIMA OF
15-30MM/DAY.
SOUTHERN CENTRAL AMERICA-NORTHERN PORTIONS OF SOUTH AMERICA ARE
UNDER INFLUENCE OF THE ITCZ/NEAR EQUATORIAL TROUGH...WITH
CONVERGENCE ZONE MEANDERING EAST ALONG 08N/10N INTO NORTHERN
COLOMBIA-NORTHWEST VENEZUELA. FAVORABLE MJO ENVIRONMENTAL
CONDITIONS IS TO ALLOW PANAMANIAN LOW TO STRENGTHEN THROUGH DAY
03. AS THE LOW STRENGTHENS...THIS WILL DRAW THE ITCZ/EQUATORIAL
TROUGH FARTHER NORTH OVER COLOMBIA/NORTH OF PANAMA...WHILE
ANCHORING ACROSS COSTA RICA TO EASTERN PACIFIC. AS A RESULT...IN A
HIGH CONFIDENCE FORECAST...EXPECTING A GRADUAL INCREASE IN
CONVECTION ACROSS THIS AREA. ACROSS COSTA RICA/SOUTHERN NICARAGUA
EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM/DAY THROUGH 60-72 HRS...AND 15-20MM/DAY AND MAXIMA OF
25-50MM AT 72-96 HRS. ACROSS PANAMA...CONVECTION IS TO INTENSIFY
THROUGH 48-72 HRS...WHEN WE EXPECT RAINFALL AMOUNT OF 15-20MM/DAY
AND MAXIMA OF 25-50MM. ACROSS COLOMBIA TO NORTHWEST VENEZUELA
EXPECTING A SIMILAR TREND. OVER EJE CAFETERO-SIERRA NEVADA DE
SANTA MARTA TO THE NORTH EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 25-50MM/DAY THROUGH 36 HRS...AND 15-30MM/DAY AND
MAXIMA OF 35-70MM/DAY AT 36-60 HRS. AS MEANDERING LOW MODULATES
CONVERGENCE ZONE NORTH...THIS WILL DECREASE TO 10-15MM/DAY AND
MAXIMA OF 20-40MM/DAY BY 96-108 HRS. OVER MARACAIBO REGION IN
NORTHWEST VENEZUELA TO SANTANDERES IN COLOMBIA INITIALLY EXPECT
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY. THROUGH
72-96 HRS THIS IS TO ALSO INCREASE TO 15-20MM/DAY AND MAXIMA OF
25-50MM/DAY.
AS MID/UPPER RIDGE PATTERN CONFINES TO WESTERN PORTIONS OF THE
DOMAIN...THIS IS ALLOWING SHORT WAVE PERTURBATION ON THE SOUTHERN
STREAM TO PROPAGATE ACROSS THE GULF OF MEXICO INTO THE NORTHERN
CARIBBEAN ISLES. IN THIS PATTERN A SHORT WAVE TROUGH IS MAKING A
BEELINE ACROSS THE SOUTHEAST BAHAMAS-EASTERN CUBA TO HISPANIOLA...
WHILE ANOTHER OVER THE GULF OF MEXICO QUICKLY FOLLOWS. SUBTROPICAL
JET MAXIMA ARE TO ACCOMPANY THESE PERTURBATIONS...FAVORING PERIODS
OF DIVERGENCE ALOFT AS THEY PROPAGATE ACROSS THE NORTHERN
CARIBBEAN ISLANDS. THE STREAMING MID LEVEL PERTURBATIONS WILL
FOCUS THEIR SHORT WAVE ENERGY ACROSS THE BAHAMAS-NORTHERN
CARIBBEAN ISLANDS. THIS QUICKLY PUTS A DENT ON MID LEVEL CAP OVER
THE NORTHEAST CARIBBEAN ISLES BY 30-33 HRS. AT LOW LEVELS...A
BROAD CELL OF THE BERMUDA RIDGE DOMINATES THE WESTERN
ATLANTIC-NORTHERN CARIBBEAN ISLANDS...SUSTAINING AN EASTERLY FLOW
ACROSS THE ISLAND CHAIN INTO THE EASTERN/CENTRAL CARIBBEAN. THE
INFLOW OF SHORT WAVE ENERGY AND GRADUAL EROSION OF MID LEVEL CAP
WILL ALLOW FOR DEEPER MOISTURE TO POOL ACROSS THE FRENCH INTO
NORTHEAST CARIBBEAN ISLES. THIS IS TO QUICKLY INCREASE THROUGH
48-54 HRS.
ACROSS THE BAHAMAS INITIALLY EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM/DAY. AS JET DYNAMICS IMPROVE
THROUGH 72-78 HRS...EXPECTING AN INCREASE IN ACTIVITY ACROSS
ANDROS-NEW PROVIDENCE-GREAT ABACO-BIMINI...WITH RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-40MM/DAY. OVER CUBA...WHERE
GENERALLY UNFAVORABLE JET DYNAMICS ARE EXPECTED TO
PREVAIL...EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM/DAY. ACROSS HISPANIOLA EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM/DAY THROUGH 48 HRS...AND 15-20MM/DAY AND
MAXIMA OF 25-50MM THEREAFTER. ACROSS PUERTO RICO TO VIRGIN ISLES
EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-30MM/DAY
AT 36-60 HRS...AND 15-20MM/DAY AND MAXIMA OF 25-50MM/DAY AT 60-84
HRS.
FARTHER EAST...OVER THE TROPICAL ATLANTIC...THE ITCZ MEANDERS WEST
ALONG 05N INTO THE GUIANAS...WHERE IT IS FORECAST TO REMAIN OVER
THE NEXT FEW DAYS. AS IT PERSISTS...EXPECTING ORGANIZED DEEP
CONVECTION TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-30MM/DAY. THROUGH 48-72 HRS THIS DECREASES TO 05-10MM/DAY
AND MAXIMA OF 15-20MM.
BLENMAN...BMS (BARBADOS)
MCKENZIE...BDM (BAHAMAS)
DAVISON/GALVEZ...WPC (USA)
$$
000
FXSA20 KWBC 201545
PMDSA
SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1144 AM EDT MON MAY 20 2013
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
MODEL COMPARISON (VALID FROM 00 UTC MAY 20): GLOBAL MODELS FOLLOW
SIMILAR PATTERN EVOLUTION THROUGH 96-108 HRS. THEY THEN START TO
DIVERGE LATER ON THE CYCLE HOW AN AMPLIFYING MID/UPPER TROUGH OVER
THE WESTERN ATLANTIC IS GOING TO EVOLVE. THE GFS IS CLOSER TO THE
MEAN OF THE GLOBAL ENSEMBLES...WHILE THE ECMWF TENDS TO DIVERGE
THE MOST. THE UKMET APPEARS AS THE COMPROMISE SOLUTION AMONG THESE
MODELS. BUT VARIABILITY IS TO HIGH TO ESTABLISH CONFIDENCE INTO
MEDIUM RANGE PERIOD. AS A RESULT...OUR CONFIDENCE IN THE FORECAST
IS LOW.
A BROAD MID/UPPER LEVEL TROUGH ON THE SOUTHERN STREAM IS
INITIALIZED OVER THE BELLINGSHAUSEN SEA TO THE EASTERN
PACIFIC/SOUTHERN CONE. THE TROUGH IS TO SLOWLY PULL ACROSS THE
ANTARCTIC PENINSULA THROUGH 84 HRS...INTO THE WEDDELL SEA BY 96
HRS. AS IT PULLS ACROSS THE ANTARCTIC PENINSULA IT WILL DRAW A
TROUGH ACROSS SOUTHERN CHILE TO PATAGONIA IN ARGENTINA...WHERE IT
IS TO FOCUS ITS SHORT WAVE ENERGY. LATER IN THE CYCLE...AND UNDER
INFLUENCE OF A BUILDING RIDGE TO THE WEST...THE TROUGH IS FORECAST
TO THEN RAPIDLY AMPLIFY ALONG THE COAST OF ARGENTINA INTO
URUGUAY/SOUTHERN STATES OF BRASIL. BY 120-132 HRS A CLOSED LOW IS
TO FORM ALONG THIS AXIS TO THE NORTH-NORTHEAST OF THE FALKLAND
ISLANDS/MALVINAS. AT LOW LEVELS IT WILL SUSTAIN A BROAD TROUGH
OVER THE BELLINGSHAUSEN SEA/ANTARCTIC PENINSULA-SOUTHERN CONE OF
SOUTH AMERICA. POLAR FRONTS WILL REVOLVE AROUND THIS AXIS AS IT
MEANDERS ACROSS THE SOUTHERN CONE...WITH SUCCESSIVE FRONTS TO
RAPIDLY MOVE ACROSS SOUTHERN CHILE/PATAGONIA IN ARGENTINA. THIS
PATTERN PERSISTS OVER THE NEXT FOUR DAY...FAVORING STRONG BOUNDARY
LAYER WINDS OF 35-50KT AND TOPOGRAPHICALLY INDUCED CONVECTION.
OVER CHILE...BETWEEN TEMUCO-ISLA DE CHILOE...THE DAILY MAXIMA WILL
PEAK AT 15-0MM OVER THE NEXT THREE DAYS...WHILE OVER TIERRA DEL
FUEGO IT IS TO GENERALLY PEAK AT 05-10MM. LATER IN THE CYCLE...AS
THE SURFACE TROUGH PATTERN OVER THE WESTERN ATLANTIC STRENGTHENS
AND A POLAR RIDGE BUILDS OVER ARGENTINA...THE SURFACE FRONT WILL
SURGE ACROSS RIO DE LA PLATA TO NORTHERN URUGUAY/SOUTHERN
BRASIL-PARAGUAY. THIS IS TO FAVOR A COLD ADVECTIVE PATTERN INTO
MID SECTIONS OF SOUTH AMERICA.
FARTHER EAST...OVER THE SOUTH ATLANTIC...A SHORT WAVE TROUGH ON
THE NORTHERN STREAM MEANDERS BETWEEN 40W-15W AND TO THE SOUTH OF
25S. MID LEVEL TROUGH IS TO REMAIN NEARLY STATIONARY DURING THE
NEXT THREE DAYS...AND LATER IN THE CYCLE IT WILL START TO MIGRATE
TO THE EAST-SOUTHEAST. AS IT HOLDS...IT WILL SUSTAIN A BROAD
SURFACE TROUGH OVER THE CENTRAL ATLANTIC...AND A POLAR FRONT THAT
TRAILS WEST INTO THE SOUTHERN STATES OF BRASIL. AN OLD BOUNDARY
LIES TO THE NORTH... WITH AXIS WEST ALONG 30S 30W...SOUTHEAST
BRASIL TO CHACO PARAGUAYO/CENTRAL BOLIVIA. UNDER INFLUENCE OF A
SUBTROPICAL JET MAXIMA THIS BOUNDARY IS FORECAST TO HOLD OVER THE
NEXT FEW DAYS... BLOCKING MOISTURE TRANSPORT TO THE NORTHERN
PORTIONS OF SOUTH AMERICA. AS THE SURFACE FRONTS MEANDER ACROSS
SOUTHERN BRASIL-SAO PAULO...THESE IS TO FAVOR SCATTERED
CONVECTION. INITIALLY EXPECTING RAINFALL AMOUNTS OF 05-10MM...AND
THROUGH 72-96 HRS THIS WILL INCREASE TO 15-20MM. OTHER ACTIVITY IS
EXPECTED ON THE TAIL END OF THIS FRONT OVER CENTRAL BOLIVIA...WITH
RAINFALL AMOUNTS OF 05-10MM.
AT 200 HPA...WEAK CELL OF THE SUBTROPICAL RIDGE EXTENDS ACROSS
NORTHERN SOUTH AMERICA...WITH AXIS CONFINING TO CONTINENTAL AREA
NORTH OF 13S/14S. ALONG THIS AXIS...MODEL GUIDANCE SHOWS CLOSED
HIGH FORMING OVER AMAZONAS IN BRASIL-NORTHERN JUNGLE OF PERU BY
72-96 HRS...WITH AXIS TO THEN BUILD WHILE GRADUALLY MIGRATING EAST
ACROSS NORTHERN STATES OF BRASIL. AS THE HIGH/RIDGE
INTENSIFIES...IT WILL INDUCE A SHORT WAVE TROUGH OVER NORTHEAST
BRASIL. RIDGE PATTERN ALOFT WILL VENT ORGANIZED DEEP CONVECTION
ACROSS COLOMBIA-NORTHERN AMAZONAS IN BRASIL TO THE NORTHERN JUNGLE
OF PERU/EASTERN ECUADOR. EARLY IN THE CYCLE EXPECTING MAXIMA IN
THIS AREA TO PEAK AT 20-45MM. AS THE MID/UPPER LEVEL TROUGH FORMS
TO THE EAST...FOCUS OF ORGANIZED CONVECTION WILL SHIFT EAST TO
PARA IN BRASIL...WITH MAXIMA IN THIS AREA TO PEAK AT 20-45MM.
OTHER CONVECTION IS EXPECTED ACROSS AMAPA TO THE AMAZON RIVER
DELTA REGION...WITH RAINFALL AMOUNTS OF 15-20MM/DAY.
MAQUEDA...DINAC (PARAGUAY)
SILVA DE SOUZA...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)
$$
000
FXUS02 KWBC 201353
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
951 AM EDT MON MAY 20 2013
VALID 12Z THU MAY 23 2013 - 12Z MON MAY 27 2013
RELIED ON THE MOST RECENT ECENS MEAN FOR THE MEDIUM-RANGE FRONTS
AND PRESSURES ACROSS THE NATION. THE LAST FOUR ECENS MEANS HAVE
BEEN QUITE STABLE, WITH THE GEFS MEANS MEANDERING TOWARD THE
EUROPEAN CENTRE GUIDANCE. DID NOT INCLUDE ANY DETERMINISTIC
SOLUTIONS IN THE MANUAL FORECAST, WITH ANY GIVEN MODEL OUT OF SYNC
WITH THE ENSEMBLE MEANS AT ONE POINT OR ANOTHER DURING THE PERIOD.
EXPECT MEAN TROUGHS OVER THE NORTHWEST AND ALONG THE EASTERN
SEABOARD, WITH A SUBTROPICAL RIDGE OVER THE SOUTH CENTRAL STATES.
AFTER THE COLD FRONTAL PASSAGE EARLY IN THE PERIOD OVER THE EAST,
MOST OF THE PRECIPITATION IS EXPECTED NORTH OF THE POLAR FRONT
FROM THE NORTHERN ROCKIES ACROSS THE NORTHERN GREAT PLAINS AND
INTO THE GREAT LAKES AND MIDWEST. COOL CONDITIONS ARE ANTICIPATED
WITH THE SURFACE HIGH BUILDING INTO THE NORTHEAST BY DAY 5, WITH
HOT WEATHER OVER THE SOUTHERN PLAINS.
CISCO
$$
000
FXSA20 KWBC 201301
PMDSA
SOUTH AMERICA SYNOPTIC DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 AM EDT MON MAY 20 2013
GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/
SYNOPSIS (VALID FROM 00 UTC MAY 20): THE 200 HPA ANALYSIS SHOWS
NARROW CELL OF THE SUBTROPICAL RIDGE WITH AXIS WEST ACROSS THE
TROPICAL ATLANTIC TO NORTHERN SOUTH AMERICA...WITH AXIS ENVELOPING
AREA TO THE NORTH OF 13S. A SHORT WAVE TROUGH OVER PERU SEPARATES
THIS RIDGE FROM ANOTHER OVER THE TROPICAL EASTERN PACIFIC. IN THIS
PATTERN...ORGANIZED TROPICAL CONVECTION CONFINES TO THE EQUATORIAL
TROUGH AS IT EXTENDS ACROSS THE GUIANAS-AMAZONIA IN VENEZUELA TO
CENTRAL/NORTHERN COLOMBIA.
THE 250 HPA JET ANALYSIS SHOWS THE SOUTHERN POLAR WITH AXIS ALONG
A 144KT MAXIMUM AT 51S 120W...49S 108W...49S 97W...55S 77W...61S
56W...61S 40W...54S 36W...EXITING AT 48S 36W. THE NORTHERN POLAR
LIES ALONG A 130KT MAXIMUM AT 42S 119W...A 134KT MAXIMUM AT 44S
108W...A 130KT MAXIMUM AT 44S 99W...44S 89W...EXITING AT 36S 83W.
THE JET REFORMS TO THE EAST NEAR 51S 72W...ALONG 56S 63W...EXITING
AT 56S 49W. THE SUBTROPICAL JET HAS A FINGER WITH ENTRANCE AT 22S
100W...ALONG 21S 91W...24S 83W...EXITING AT 28S 76W. IT REFORMS AT
35S 61W...ALONG 35S 49W...29S 32W...AND 25S 20W. THE SUBTROPICAL
HAS ANOTHER BRANCH TO THE NORTH WITH ENTRANCE AT 16S 113W...ALONG
16S 101W...17S 86W...EXITING AT 19S 72W. IT REFORMS AT 20S
70W...ALONG 26S 59W...A 134KT MAXIMUM AT 27S 46W...34S
39W...EXITING AT 20S 32W.
AT 500 HPA...A DEEP LOW ON THE SOUTHERN STREAM CENTERING NEAR 64S
99W ANCHORS A BROAD TROUGH T THE SOUTH OF 44S. THIS IS INTERACTING
WITH A NORTHERN STREAM TROUGH THAT EXTENDS TO THE NORTHWEST ALONG
A CLOSED LOW NEAR 43S 81W...30S 90W...20S 100W...TO 17S 100W. A
SHORT WAVE TROUGH OVER CENTRAL ARGENTINA PRECEDES THIS AXIS...WITH
SHORT WAVE ENERGY FOCUSING ACROSS LA PAMPA TO SOUTHERN BUENOS
AIRES PROVINCE. THE TROUGH IS PRESSING AGAINST A RIDGE TO THE EAST
THAT EXTENDS FROM RIO GRANDE DO SUL IN BRASIL...ALONG 50S
50W...60S 40W...TO THE WEDDELL SEA. ANOTHER TROUGH TO THE EAST
EXTENDS BETWEEN 40W-10W AND TO THE SOUTH OF 20S...WITH SHORT WAVE
PERTURBATIONS REVOLVING AROUND THE LONG WAVE AXIS.
AT LOW LEVELS...THE SURFACE ANALYSIS SHOWS A BROAD TROUGH ON THE
SOUTHERN STREAM THAT CENTERS ON A DEEP OCCLUDED 934 HPA LOW AT 64S
95W. POLAR FRONTS REVOLVE AROUND THIS AXIS WITH ONE EXTENDING
ALONG A 968 HPA LOW AT 64S 69W...59S 73W...57S 80W...A 970 HPA LOW
AT 56S 88W...51S 87W...48S 93W...A 998 HPA LOW AT 46S 98W...41S
101W...AND 40S 111W. ANOTHER FRONT TO THE NORTH LIES ALONG A 988
HPA LOW AT 64S 47W...58S 53W...A 1006 HPA LOW AT 55S 63W...50S
68W...47S 75W...A 1014 HPA LOW AT 43S 79W...41S 75W...JUAN
FERNANDEZ ISLAND...AND 31S 85W. A RIDGE ON THE NORTHERN STREAM
LIES TO THE WEST...AS IT CENTERS ON TWO 1027 HPA HIGHS...WITH ONE
AT 33S 104W AND THE OTHER AT 36S 88W. FARTHER EAST...OVER THE
ATLANTIC...ANOTHER RIDGE ON THE NORTHERN STREAM CENTERS ON A 1025
HPA HIGH AT 45S 49W. A SHORT WAVE TROUGH TO THE EAST CENTERS ON AN
OCCLUDED 1000 HPA LOW AT 43S 34W. FARTHER NORTH...AN ELONGATED
FRONT LIES ALONG A 1006 HPA LOW AT 29S 17W...22S 17W...18S
26W...17S 34W...TO A 1018 HPA LOW OVER SOUTHERN BRASIL...CHACO
PARAGUAYO TO CENTRAL BOLIVIA. THIS FAVORS SCATTERED CONVECTION
ACROSS SOUTHERN BRASIL. A SECONDARY FRONT TO THE SOUTH EXTENDS
FROM A 1020 HPA LOW AT 36S 56W TO SOUTHERN URUGUAY TO 30S 60W.
MAQUEDA...DINAC (PARAGUAY)
SILVA DE SOUZA...INMET (BRASIL)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)
$$
000
FXCA20 KWBC 201048
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
647 AM EDT MON MAY 20 2013
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. NARROW UPPER
LEVEL RIDGE EXTENDS WEST-TO-EAST ACROSS THE BASIN. AS THE RIDGE
CONFINES TO THE SOUTH OF 20N...THIS IS ALLOWING SHORT WAVE
PERTURBATIONS TO STREAM ACROSS THE GULF INTO THE NORTHERN
CARIBBEAN ISLANDS. IN THIS PATTERN A SHORT WAVE TROUGH IS MAKING A
BEELINE ACROSS THE BAHAMAS-CUBA...WHILE ANOTHER OVER THE GULF OF
MEXICO QUICKLY FOLLOWS. AT MID LEVELS...RIDGE PATTERN FAVORS A CAP
INVERSION ACROSS THE FORECAST AREA. BUT THIS IS EXPECTED TO
GRADUALLY WEAKEN OVER THE NEXT 18-24 HRS AS PERTURBATIONS BEGIN TO
STREAM ACROSS THE FORECAST AREA. AT LOW LEVELS...BROAD RIDGE OVER
THE WESTERN ATLANTIC SUSTAINS AN EASTERLY FLOW ACROSS THE NORTHERN
CARIBBEAN ISLES. INFLOW OF SHORT WAVE ENERGY AND GRADUAL EROSION
OF MID LEVEL CAP WILL ALLOW FOR DEEPER MOISTURE TO POOL ACROSS THE
FORECAST AREA. THIS IS TO START POOLING LATER ON TUESDAY AND REACH
MAXIMA DURING THE DAY ON WEDNESDAY...LEADING TO GRADUAL INCREASE
IN CONVECTION ACROSS FORECAST AREA AS THE WEEK WEARS ON.
ALTHOUGH MODELS TRENDING TOWARDS A WETTER SOLUTION THEY TEND TO
DISAGREE ON ITS INTENSITY. PER THE GFS GUIDANCE THE PWAT COULD
REACH AS HIGH AS 55-60MM DURING THE DAY ON WEDNESDAY...WHILE THE
UKMET AND ECMWF SHOW PWAT MAXIMA OF 45-50MM. AS THEY DIVERGE ON
AVAILABLE MOISTURE...THEY DIVERGE ON IMPACT THIS IS GOING TO HAVE
ACROSS THE FORECAST AREA. BOTH EUROPEAN MODELS GENERALLY FAVOR
MAXIMA OF LESS THAN AN INCH...WHILE THE GFS SHOWING MAXIMA OF A
COUPLE INCHES. AS FORECAST AREA LIES ON NORTHERN FRINGES OF MJO
IMPULSE CROSSING THE BASIN...WE ARE SOMEWHAT OPTIMISTIC THAT THIS
IS GOING TO LEAD TO INCREASE IN ACTIVITY. SO AT THIS TIME...
LEANING TOWARDS THE WETTER GFS SOLUTION.
DISCUSSION FROM MAY 20/00UTC:
BLENMAN...BMS (BARBADOS)
MCKENZIE...BDM (BAHAMAS)
DAVISON/GALVEZ...WPC (USA)
$$
000
FXUS01 KWBC 200841
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
440 AM EDT MON MAY 20 2013
VALID 12Z MON MAY 20 2013 - 12Z WED MAY 22 2013
...MODERATE RISK OF SEVERE WEATHER FOR EASTERN OKLAHOMA AND THE
SOUTHERN OZARKS THROUGH TUESDAY MORNING...
...SLIGHT RISK OF SEVERE WEATHER FOR THE MIDWEST AND UPPER HALF OF
THE MISSISSIPPI VALLEY TODAY AND TONIGHT...
...HEAVY RAINFALL POSSIBLE FOR THE UPPER MISSOURI AND MISSISSIPPI
VALLEYS...
...SLOW-MOVING PACIFIC SYSTEM TO BRING RAINFALL...WINDY CONDITIONS
AND COOLER WEATHER TO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES...
DEEP...SLOW-MOVING TROUGH OF LOW PRESSURE IN THE NORTH CENTRAL
PLAINS AND BROAD FETCH OF MOIST...SOUTHERLY FLOW OFF THE GULF OF
MEXICO IS EXPECTED TO PRODUCE WIDESPREAD SHOWERS...THUNDERSTORMS
AND LOCALLY HEAVY RAINFALL OVER A LARGE PORTION OF THE
PLAINS...MIDWEST AND CENTRAL GREAT LAKES TODAY AND TUESDAY. ALONG
WITH THE THREAT OF HEAVY RAINFALL...THERE IS A MODERATE RISK OF
SEVERE STORMS FOR THE SOUTHERN PLAINS AND OZARKS AND A SLIGHT RISK
OF SEVERE WEATHER FOR THE UPPER HALF OF THE MISSISSIPPI VALLEY.
PLEASE REFER TO THE STORM PREDICTION CENTER FOR THE LATEST
INFORMATION AND UPDATES CONCERNING THE POTENTIAL SEVERE WEATHER
THREAT THROUGH TUESDAY MORNING.
OUT WEST...LOW PRESSURE IN THE GULF OF ALASKA WILL SLOWLY MOVE
ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. INLAND...LOW
PRESSURE IS EXPECTED TO INTENSIFY OVER SOUTHWEST CANADA WITH AN
INCREASE IN SOUTHERLY FLOW AND THREAT FOR MOUNTAIN SHOWERS AND
THUNDERSTORMS. BY TUESDAY MORNING...A STRONG COLD FRONT AND WINDY
CONDITIONS SURGES ACROSS THE CASCADES AND SPREADS COOLER AND
WETTER WEATHER INTO THE NORTHERN ROCKIES AND PRODUCES SCATTERED
SHOWERS AND A FEW THUNDERSTORMS INTO WESTERN SECTIONS OF
WASHINGTON AND OREGON.
IN THE EAST...SCATTERED SHOWERS WILL CONTINUE ACROSS MAINE AND
PORTIONS OF NORTHERN NEW ENGLAND THROUGH THIS EVENING...AS A
SLOW-MOVING CANADIAN COLD FRONT SWEEPS INTO THE NORTH ATLANTIC.
FOR MONDAY NIGHT AND TUESDAY...A BROAD WARM FRONT AND MORE HUMID
CONDITIONS WILL WORK THEIR WAY UP THE EAST COAST...WITH THE THREAT
OF SHOWERS AND A FEW THUNDERSTORMS FOR THE MID-ATLANTIC
STATES...APPALACHIANS AND NORTHEAST...INCLUDING THE UPPER OHIO
VALLEY AND EASTERN GREAT LAKES.
VOJTESAK
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$
000
FXUS02 KWBC 200545
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
144 AM EDT MON MAY 20 2013
VALID 12Z THU MAY 23 2013 - 12Z MON MAY 27 2013
...OVERVIEW AND MODEL PREFERENCES...
THE MODELS CONTINUE TO FCST 500 MB TROUGHS ALONG BOTH WEST/EAST
COASTS AND A RIDGE OVER THE CENTRAL STATES AND A CLOSED
ANTICYCLONE OVER NORTHERN MEXICO THROUGH THE WEEKEND INTO EARLY
NEXT WEEK. THE DEEPER LOW IN THE PAC NW IS FORECAST TO YIELD 500
MB HEIGHTS ABOUT 1 TO 2 STD DEVIATIONS BELOW NORMAL AND ABOUT 1
STD DEVIATION BELOW NORMAL IN THE NORTHEAST. RIDGING ALONG 100W
BY LATE IN THE WEEK SHOULD AVERAGE AROUND 2 STD DEVIATIONS ABOVE
NORMAL ALL THE WAY FROM THE RIO GRANDE VALLEY TO SOUTH CENTRAL
CANADA AND BEYOND.
THE CLOSED LOW OVER THE PAC NW WED-FRI IS FCST BY THE
MODEL/ENSEMBLE MEAN MAJORITY TO EJECT NORTH INTO CANADA OVER THE
WEEKEND. BETTER THAN AVERAGE AGREEMENT IS SEEN AMONG THE GUIDANCE
THROUGH FRI/D5 BEFORE SMALLER DETAILS AMONG THE MODELS AMPLIFY.
THE QUESTION BECOMES HOW DEEP WILL THE ENERGY BY THAT ROTATES
THROUGH THE BASE OF THE TROUGH IN THE PACIFIC NORTHWEST INTO
NORCAL OVER NEXT WEEKEND INTO THE EARLY PART OF THE WEEK. OPTED TO
SPLIT THE DIFFERENCE AMONG THE SOLUTIONS GIVEN THE UNCERTAINTY IN
THE PHASING OF THE STREAMS ACROSS THE NORTHEAST PACIFIC.
IN THE EAST... THE MODELS/ENSEMBLES SHOW AN UPPER TROUGH MOVING
FROM THE GREAT LAKES AND ACROSS THE NORTHEAST OVER THE
WEEKEND....THEN DEPARTING EARLY NEXT WEEK AS UPSTREAM RIDGING IN
THE NORTHERN PLAINS BUILDS INTO THE UPPER MS VALLEY.
MANUAL PROGS USED A BLEND OF THE 18Z GFS/18Z GEFS MEAN/12Z ECMWF
AND 12Z ECENS MEAN HEIGHTS/SEA LEVEL PRESSURES...AS WELL AS THE
TEMPERATURES/PROBABILITY OF PRECIP FCSTS.
...SENSIBLE WEATHER HIGHLIGHTS...
BELOW NORMAL TEMPERATURES ARE EXPECTED INVOF THE SLOW-MOVING
UPPER-LEVEL TROUGH AND CUTOFF LOW IN THE PACIFIC NORTHWEST TO
NORTHERN ROCKIES...UNTIL THE PRIMARY LOW EJECTS INTO CANADA NEXT
WEEKEND. WET CONDITIONS ARE EXPECTED OVER NORTH CENTRAL MT AS
850-700 MB MOISTURE TRANSPORT AND CONVERGENCE OCCUR THU...WITH
COVERAGE WANING NEXT WEEKEND AS THE UPPER LOW MOVES INTO CANADA
AND THE MOISTURE TRANSPORT/LOW LEVEL CONVERGENCE WEAKENS. BELOW
NORMAL TEMPS ALSO DEVELOP WITH THE UPPER TROUGH ACROSS NY/NEW
ENGLAND NEXT WEEKEND.
ABOVE NORMAL TEMPS SHOULD PERSIST ACROSS THE NORTHERN AND SOUTHERN
PLAINS AND SOUTHERN ROCKIES AS AREAS OF 700 MB TEMPS 1-2 STD
DEVIATIONS ABOVE NORMAL PERSIST THROUGH NEXT WEEKEND INTO MON 27
MAY PER THE ENSEMBLES. SOUTHERLY FLOW AHEAD OF THE TROUGH AND SFC
LOW/WARM FRONT DEVELOPMENT SHOULD FOCUS PRECIP OVER THE CENTRAL
PLAINS LATE IN THE WEEKEND AND INTO THE NORTHERN PLAINS/MID-UPPER
MS VALLEY EARLY NEXT WEEK WHERE CONVECTION IS LIKELY AS INDICATED
IN THE GFS/ECMWF/MULTIPLE ENSEMBLE MEMBERS WITHIN A LOW-MID LEVEL
WARM ADVECTION PATTERN UNDERNEATH UPPER DIVERGENCE MAXIMA/LOW
LEVEL CONVERGENCE MAXIMA.
PETERSEN
$$
000
FXUS01 KWBC 191957
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
357 PM EDT SUN MAY 19 2013
VALID 00Z MON MAY 20 2013 - 00Z WED MAY 22 2013
...MODERATE RISK OF SEVERE WEATHER FOR EASTERN KANSAS AND
NORTHEAST OKLAHOMA...
...SLIGHT RISK OF SEVERE WEATHER FOR PARTS OF THE UPPER
MISSISSIPPI VALLEY TO PARTS OF THE SOUTHERN PLAINS...
...HEAVY RAINFALL POSSIBLE FOR THE UPPER MIDWEST...
QUASI-STATIONARY STORM OVER THE PLAINS WILL PRODUCE SHOWERS AND
THUNDERSTORMS OVER THE CENTRAL/SOUTHERN PLAINS AND PARTS OF THE
UPPER/MIDDLE MISSISSIPPI THAT WILL MOVE INTO THE GREAT LAKES/OHIO
VALLEY AND PARTS OF THE NORTHEAST TO THE LOWER MISSISSIPPI
VALLEY/SOUTHERN PLAINS BY TUESDAY. IN ADDITION, LIGHT TO MODERATE
RAIN WILL DEVELOP OVER UPPER MIDWEST, WANING TO RAIN OVER THE
NORTHERN PLAINS BY TUESDAY.
ADDITIONAL UPPER-LEVEL ENERGY WILL MOVE INTO THE STORM AIDING IN
THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER PARTS OF THE
NORTHERN/CENTRAL ROCKIES DURING THE AFTERNOON AND EVENING HOURS OF
SUNDAY AND MONDAY. DURING THE NIGHTTIME AND MORNING HOURS, THE
PRECIPITATION WILL BE MAINLY IN THE FORM OF RAIN OVER THE REGION
THROUGH MONDAY.
A DEEPENING UPPER-LEVEL LOW OVER THE GULF OF ALASKA WILL ROTATE
JUST OFF THE PACIFIC NORTHWEST COAST MONDAY NIGHT INTO TUESDAY.
THE ENERGY WILL PRODUCE RAIN OVER PARTS OF THE PACIFIC NORTHWEST
INTO PARTS OF NORTHERN CALIFORNIA ON TUESDAY MORNING.
ELSEWHERE, MUCH WEAKER UPPER-LEVEL LOW OVER THE SOUTHERN
MID-ATLANTIC WILL PRODUCE SHOWERS AND THUNDERSTORMS OVER PARTS OF
THE SOUTHEAST/MID-ATLANTIC SUNDAY THROUGH TUESDAY.
ZIEGENFELDER
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$
000
FXUS06 KWBC 191900
PMDMRD
PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SUN MAY 19 2013
THERE IS NO FORECASTER MESSAGE WRITTEN ON WEEKENDS
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.
THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS
THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "F"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "INCHES"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL
BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY
EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY
SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A
FORECAST OF LITTLE OR NO PRECIPITATION.
THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN
THE CLIMATE OUTLOOKS.
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
20010504 - 19650504 - 19850513 - 19820501 - 19580514
ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19850513 - 19820430 - 19650505 - 20010505 - 20070503
6 TO 10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 25 - 29, 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B A NRN CALIF B B
SRN CALIF B B IDAHO N B NEVADA B B
W MONTANA N A E MONTANA A A WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK B B
VERMONT B B NEW HAMP N B MAINE B B
MASS N B CONN N B RHODE IS N B
PENN N B NEW JERSEY B B W VIRGINIA A B
MARYLAND N B DELAWARE B B VIRGINIA N B
N CAROLINA B B S CAROLINA B A GEORGIA A B
FL PNHDL N A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN B N AK WESTERN A A AK INT BSN A B
AK S INT A B AK SO COAST A B AK PNHDL A B
8 TO 14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 27 - JUN 02, 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B N NRN CALIF B B
SRN CALIF B B IDAHO N B NEVADA N B
W MONTANA N A E MONTANA A A WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA N A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A N
TENNESSEE A A ALABAMA A B NEW YORK A A
VERMONT A N NEW HAMP A N MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A B DELAWARE N B VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A B
FL PNHDL A N FL PENIN B N AK N SLOPE A A
AK ALEUTIAN B B AK WESTERN A B AK INT BSN A N
AK S INT A B AK SO COAST A B AK PNHDL A N
LEGEND
TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN
A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN
B - BELOW B - BELOW
THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.
FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.
$$
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