Start of the EPAC season

[Hurricanehink]

Two little questions. When does the EPAC season officially start? 0000 UTC on May 15, or whenever it would correspond to the EPAC season?

Also (as a followup), would the first outlook be tonight at 11 p.m. (which would still be May 14 in the EPAC), or 5 p.m. (which would be more than 7 hours after May 15 in UTC)?

I know it's pedantic, but I'm curious!

[RL3AO]

First TWO will be issued at 12z (5am PDT) tomorrow.

[Hurricanehink]

Thanks!

[cycloneye]

Just in time as the EPAC season starts,there is an area that looks a little bit interesting.



From discussion by TPC.

A 1010 MB LOW HAS FORMED NEAR 08N101W WITH SCATTERED MODERATE TO
STRONG CONVECTION OCCURRING WITHIN 210 NM OF THE LOW CENTER IN
THE NW QUADRANT AND WITHIN 180 NM IN THE SE QUADRANT. THE LOW IS
UNDER THE ABOVE MENTIONED UPPER ANTICYCLONE WHICH WOULD BE
FAVORABLE FOR IT TO MAINTAIN ITSELF AS IT MOVES TO THE W AROUND
5-10 KT DURING THE NEXT 24 HOURS.

[KWT]

Either way, the EPAC 2010 season is pretty much with us now....how time does fly by!

[Aquawind]

AXPZ20 KNHC 150927
TWDEP

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAY 15 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 91W FROM 03N TO 09N MOVING W AT
NEAR 10 KT. THIS WAVE SHOWS UP WELL IN THE TOTAL PRECIPITABLE
WATER IMAGERY. SOME SHOWER AND TSTM ACTIVITY IS NOTED BEHIND THE
WAVE AXIS.

...ITCZ...

THE ITCZ AXIS IS ALONG AXIS ALONG 06N78W TO 07N103W TO 09N113W
TO 07N130W TO 08N140W. SCATTERED MODERATE TO ISOLATED STRONG
FROM 04N TO 08N BETWEEN 92W AND 99W. SIMILAR CONVECTION IS NOTED
NEAR 07N79W AND ALONG THE COAST OF COLOMBIA N OF 4N. SCATTERED
MODERATE IS WITHIN 120 NM N OF AXIS BETWEEN 121W AND 130W...AND
WITHIN 100 NM N OF AXIS W OF 133W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM NORTHERN BAJA CALIFORNIA TO
NEAR 26N117W. AN UPPER LEVEL RIDGE IS IN PLACE W OF THE TROUGH
WITH ANOTHER UPPER LEVEL TROUGH NOW APPROACHING THE FAR NW
PORTION OF THE AREA. MODERATE TO STRONG UPPER LEVEL SUBSIDENCE
AND IMPLIED DRY AIR MASS IS NOTED N OF 20N AND W OF 110W WITH A
BAND OF MOISTURE CURRENTLY ENTERING THE FAR NW PORTION OF THE
FORECAST REGION.

AN UPPER ANTICYCLONE IS CENTERED NEAR 10N103W WITH A RIDGE
EXTENDING TO THE NE OVER SE MEXICO AND NORTHERN CENTRAL AMERICA
AND TO THE W ALONG 10N TO 140W. A JETSTREAM BRANCH WITH CORE
WIND SPEEDS OF 70-90 KT LIES BETWEEN THE AFOREMENTIONED TROUGH
AND THIS ANTICYCLONE ENTERING THE DISCUSSION AREA NEAR 18N140W
AND CONTINUING TO THE E-NE AROUND THE NORTHERN PERIPHERY OF THE
ANTICYCLONE AND INTO CENTRAL MEXICO. WATER VAPOR IMAGERY SHOWS A
BAND OF TRANSVERSE HIGH CLOUDS ASSOCIATED WITH THIS JET. THE
RIDGE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ.

AT THE SURFACE...A 1025 MB HIGH PRES CENTERED NEAR 30N138W
EXTENDS A RIDGE OVER THE FORECAST WATERS TO NEAR 17N120W. A
WINDSAT PASS FROM AROUND 0300 UTC AND THE SUBSEQUENT 0634 UTC
ASCAT PASS INDICATED A BROAD AREA OF FRESH TO STRONG TRADE WINDS
OF 20 TO 25 KT ON THE SOUTHERN PERIPHERY OF THE HIGH WHICH IS
FORECAST TO REMAIN NEARLY STATIONARY DURING THE NEXT 24 HOUR
THEN WILL WEAKEN IN ABOUT 48 HOURS AS A COLD FRONT MOVES INTO
THE NW PORTION OF THE AREA.

A WEAK 1010 MB LOW PRES IS CENTERED NEAR 07.5N105W. CONVECTION
HAS DIMINISHED OVERNIGHT DUE TO SOME UPPER LEVEL NLY SHEAR AND
ONLY SOME CONVECTIVE ACTIVITY IS OBSERVED WITHIN 120 NM OF
CENTER IN SE QUADRANT. MOST OF THE COMPUTER MODELS KEEP A WEAK
SYSTEM MOVING MAINLY WWD DURING THE NEXT 48-72 HOURS.

NE WIND WAVES AND CROSS EQUATORIAL SW SWELL DOMINATE THE
MAJORITY OF THE FORECAST REGION. THE SEA STATE WILL BECOME MORE
COMPLEX DURING THE NEXT 24-48 HOURS AS A SET OF LONG PERIOD SE
SWELL BEGINS TO PROPAGATE N OF THE EQUATOR.

GAP WINDS...NE TO E WINDS AT 20 KT ARE SURGING THROUGH THE GULF
OF PAPAGAYO DOWNWIND TO 90W. THESE WINDS ARE EXPECTED TO
DIMINISH TO LESS THAN 20 KT IN ABOUT 24 HOURS.

OF NOTE...TODAY MARKS THE BEGINNING OF THE 2010 EASTERN NORTH
PACIFIC HURRICANE SEASON WHICH RUNS FROM MAY 15 TO NOVEMBER 30.
ON AVERAGE...SIXTEEN TROPICAL STORMS FORM EVERY YEAR...NINE OF
WHICH WILL BECOME HURRICANES WITH 4 REACHING MAJOR STATUS. THE
FIRST TROPICAL STORM THIS SEASON WILL BE NAMED AGATHA.$$
GR

images/smilies/12.gif

[Kingarabian]

Is this the system you guys were talking about over at the medium/long range model run's thread?

[cycloneye]

000
ABPZ20 KNHC 151137
TWOEP
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT SAT MAY 15 2010

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

TODAY MARKS THE FIRST DAY OF THE EASTERN NORTH PACIFIC HURRICANE
SEASON...WHICH WILL RUN UNTIL NOVEMBER 30. LONG-TERM AVERAGES
HURRICANES ARE 15...9...AND 4...RESPECTIVELY.

THE LIST OF NAMES FOR 2010 IS AS FOLLOWS:

[b]Agatha
Blas
Celia
Darby
Estelle
Frank
Georgette
Howard
Isis
Javier
Kay
Lester
Madeline
Newton
Orlene
Paine
Roslyn
Seymour
Tina
Virgil
Winifred
Xavier
Yolanda
Zeke

THIS PRODUCT...THE TROPICAL WEATHER OUTLOOK...BRIEFLY DESCRIBES
SIGNIFICANT AREAS OF DISTURBED WEATHER AND THEIR POTENTIAL FOR
TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS. BEGINNING THIS
YEAR...THE OUTLOOK WILL INCLUDE A QUANTITATIVE FORECAST OF THE
PROBABILITY OF GENESIS FOR EACH DISTURBANCE. THE ISSUANCE TIMES OF
THIS PRODUCT ARE 5 AM...11 AM...5 PM...AND 11 PM PDT. AFTER THE
CHANGE TO STANDARD TIME IN NOVEMBER...THE ISSUANCE TIMES ARE 4
AM...10 AM...4 PM...AND 10 PM EST.

PRIOR TO 2009...THE SPECIAL TROPICAL DISTURBANCE STATEMENT
COULD BE ISSUED AT ANY TIME TO DESCRIBE SIGNIFICANT DISTURBANCES
IN BETWEEN ISSUANCES OF THE TROPICAL WEATHER OUTLOOK. THE
SPECIAL TROPICAL DISTURBANCE STATEMENT WAS DISCONTINUED IN 2009 AND
IS NO LONGER ISSUED. INSTEAD...A SPECIAL TROPICAL WEATHER
OUTLOOK WILL BE ISSUED TO PROVIDE UPDATES...AS NECESSARY...IN
BETWEEN THE REGULARLY SCHEDULED ISSUANCES OF THE TROPICAL WEATHER
OUTLOOK. SPECIAL TROPICAL WEATHER OUTLOOKS WILL BE ISSUED UNDER
THE SAME WMO AND AWIPS HEADERS AS THE REGULAR TROPICAL WEATHER
OUTLOOKS.

A STANDARD PACKAGE OF PRODUCTS...CONSISTING OF THE TROPICAL
CYCLONE PUBLIC ADVISORY...THE FORECAST/ADVISORY...THE CYCLONE
DISCUSSION... AND A WIND SPEED PROBABILITY PRODUCT...IS ISSUED
EVERY SIX HOURS FOR ALL ONGOING TROPICAL CYCLONES. IN
ADDITION...A SPECIAL ADVISORY PACKAGE MAY BE ISSUED AT ANY TIME
TO ADVISE OF SIGNIFICANT UNEXPECTED CHANGES OR TO MODIFY WATCHES
OR WARNINGS.

THE TROPICAL CYCLONE UPDATE IS A BRIEF STATEMENT TO INFORM OF
SIGNIFICANT CHANGES IN A TROPICAL CYCLONE OR TO POST OR CANCEL
WATCHES OR WARNINGS. IT IS USED IN LIEU OF OR TO PRECEDE THE
ISSUANCE OF A SPECIAL ADVISORY PACKAGE. TROPICAL CYCLONE
UPDATES...WHICH CAN BE ISSUED AT ANY TIME...CAN BE FOUND UNDER
WMO HEADER WTPZ61-65 KNHC...AND UNDER AWIPS HEADER MIATCUEP1-5.

ALL NATIONAL HURRICANE CENTER TEXT AND GRAPHICAL PRODUCTS ARE
AVAILABLE ON THE WEB AT http://WWW.NHC.NOAA.GOV

$$
FORECASTER STEWART

[brunota2003]

Nice to see that name again at the bottom!