000
FXPQ60 PGUM 190757
AFDPQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
557 PM CHST SUN SEP 19 2010
.SYNOPSIS...
PGUA WSR-88D SHOWS ISOLATED SHOWERS IN THE MARIANAS WATERS... WITH
SCATTERED SHOWERS DEVELOPING JUST TO THE SOUTHEAST. THESE SHOWERS
ARE ASSOCIATED WITH A DEVELOPING TROPICAL DISTURBANCE ABOUT 400
MILES EAST OF GUAM. THE MAIN AREA OF SHOWERS WITH THIS DISTURBANCE
IS BETWEEN 10N AND 20N FROM 150E TO 160E. ELSEWHERE A TRADE- WIND
TROUGH IS CREATING SCATTERED SHOWERS JUST EAST AND NORTH OF YAP.
TRADE-WIND CONVERGENCE IS GENERATING SCATTERED SHOWERS WITHIN 100
MILES OF A LINE FROM 1.5N 137E TO 10N 157E.
&&
.DISCUSSION...
DEVELOPING TROPICAL DISTURBANCE EAST OF THE MARIANAS IS
DEFINITELY THE 800 POUND GORILLA IN THE FORECAST ROOM TONIGHT. IT
IS NOW THE SUBJECT OF A TROPICAL CYCLONE FORMATION ALERT FROM THE
JOINT TYPHOON WARNING CENTER. SINCE IT IS JUST BEGINNING TO PULL
ITSELF TOGETHER...WINDS WILL REMAIN FAIRLY LOW...WITH RAIN BEING
THE BIG STORY. THE NEXT FEW HOURS DO NOT LOOK SO BAD...SO WENT
WITH SCATTERED LOCALLY HEAVY SHOWERS AFTER MIDNIGHT AND MONDAY.
THE CONVECTION WITH THE DISTURBANCE IS WEAKENING AT THE MOMENT
BUT WILL ATTRIBUTE THAT TO CYCLING...A COMMON PHENOMENON WITH
NASCENT TROPICAL CYCLONES. EXPECT IT TO PICK UP AGAIN IN A FEW
HOURS. THIS ALSO AGREES WELL WITH THE GENERAL DIURNAL CYCLE SO
FOR ALL THOSE REASONS AFTER MIDNIGHT SEEMED TO BE THE BEST BET.
JUST COULD NOT FIND ANY WIND GRIDS THAT DEFINITELY SEEMED BETTER
THAN THE CURRENT GRIDS SO DID NOT CHANGE THE WINDS AT ALL. IN
FACT...LIGHT AND VARIABLE SEEMS GOOD BASED ON THE ASCAT OF 10
KNOTS OR LESS THROUGHOUT THE LATITUDES OF THE MARIANAS WATERS.
TWEAKED TEMPERATURES TONIGHT AND MONDAY DOWN BASED ON EXPECTED
RAINFALL. AS HAS BEEN THE PATTERN THIS YEAR...VIRTUALLY ALL
TROPICAL CYCLONE ACTIVITY IS DEVELOPING AT THE UPPER-LEVEL
ANTICYCLONIC AREAS BETWEEN THE CELLS OF THE TROPICAL UPPER
TROPOSPHERIC TROUGH.
000
WWMY80 PGUM 191845
SPSMY
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
445 AM CHST MON SEP 20 2010
GUZ001>004-200800-
GUAM-ROTA-TINIAN-SAIPAN-
445 AM CHST MON SEP 20 2010
A DEVELOPING TROPICAL DISTURBANCE NORTHEAST OF THE MARIANAS REMAINS
THE SUBJECT OF A TROPICAL CYCLONE FORMATION ALERT FROM THE JOINT
TYPHOON WARNING CENTER. AT 4 AM THE CENTER WAS ESTIMATED FROM
SATELLITE TO BE NEAR 17N AND 148E...ABOUT 325 MILES NORTHEAST OF
GUAM AND 200 MILES NORTHEAST OF SAIPAN. MOVEMENT WAS GENERALLY
TOWARD THE NORTHWEST.
AS THE DISTURBANCE MOVES NORTHWEST TODAY AND TONIGHT...SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE MARIANA
ISLANDS...WITH UP TO 3 INCHES POSSIBLE THROUGH TUESDAY MORNING. THIS
COULD RESULT IN MINOR FLOODING OF ROADS AND POOR-DRAINAGE AREAS.
SINCE THE DISTURBANCE IS STILL IN ITS BEGINNING STAGE...STRONG WINDS
ARE NOT EXPECTED. HOWEVER...RESIDENTS OF FAR NORTHERN ISLANDS SUCH
AS PAGAN AND AGRIHAN SHOULD MONITOR THE PROGRESS OF THIS DISTURBANCE
THROUGH TONIGHT.
$$
MIDDLEBROOKE
Still pretty disorganized on IR:
Dvorak's 1.5 from PGTW (JTWC) and 1.0 from KNES.
TPPN11 PGTW 191809
A. TROPICAL DISTURBANCE 90W (EAST OF GUAM)
B. 19/1732Z
C. 16.8N
D. 148.1E
E. FIVE/MTSAT
F. T1.5/1.5/D0.5/24HRS STT: S0.0/06HRS
G. IR/EIR
H. REMARKS: 70/PBO ANMTN. CONVECTION WRAPPED A .30 ON LOG 10
SPIRAL YIELDING A DT OF 1.5. MET AND PT AGREE. DBO DT.
I. ADDITIONAL POSITIONS:
19/1237Z 16.5N 148.5E TRMM
GATES
TXPN28 KNES 191517
SIMWIR
A. TROPICAL DISTURBANCE (90W)
B. 19/1432Z
C. 15.1N
D. 150.2E
E. FIVE/MTSAT
F. T1.0/1.0/D1.0/24HRS
G. IR/EIR/SWIR
H. REMARKS...NO CONFIDENCE IN CENTER LOCATION (IF THERE IS EVEN A LLC).
CONVECTION IS DECENT BUT NOT MUCH BANDING ASSOCIATED WITH THE MAIN
AREA...DISTANT BAND TO THE EAST IS .2 BUT DT IS 0.0 FOR NO CURVATURE OF
MAIN CLUSTER. MET IS 1.0. PT IS 0. FT BASED ON MET. SWIR AND MI DO NOT
HINT AT CIRCULATION BUT CANNOT RULE IT OUT...AND WILL NOT WEAKEN SYSTEM
IN FIRST 24HRS OVERNIGHT.
I. ADDL POSITIONS
NIL
...GALLINA
=
Not convincing on ASCAT:
