WDIO31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07A (SEVEN) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.5N 67.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 662 NM SOUTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 11 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS RAGGED
DEEP CONVECTION CONTINUING TO FLARE AROUND A LOW-LEVEL CIRCULATION
CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON FORWARD EXTRAPOLATION OF A SUBTLE MICROWAVE EYE
FEATURE EVIDENT IN A 142112Z GMI 37GHZ MICROWAVE IMAGE. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF
SUBJECTIVE AGENCY DVORAK INTENSITY ESTIMATES RANGING FROM T2.0 TO
T3.0, WITH THE ASSUMPTION THAT THE SATCON INTENSITY ESTIMATE MAY BE
A BIT HIGH GIVEN THAT THE RAGGED STRUCTURE OF THE FLARING
CONVECTION HAS NOT IMPROVED SINCE THE PREVIOUS SCATTEROMETERY PASS.
OUTFLOW IS RESTRICTED EQUATORWARD BUT MODERATE POLEWARD, AND THE
SYSTEM IS ENCOUNTERING 10 TO 15 KNOTS OF VERTICAL WIND SHEAR.

INITIAL WIND RADII BASIS: OTHER 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS SATCON: 46 KTS AT 142057Z
   CIMSS ADT: 39 KTS AT 150015Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 07A CONTINUES TO TRACK
TOWARD THE WEST-NORTHWEST UNDER THE STEERING INFLUENCE OF A WEAK
STR TO THE NORTH. ENVIRONMENTAL CONDITIONS ARE ONLY MARGINAL FOR
DEVELOPMENT AT THIS TIME. ALTHOUGH THE SYSTEM REMAINS OVER SEA
SURFACE TEMPERATURES OF 28 TO 29 DEGREES CELSIUS WITH MODERATE
POLEWARD OUTFLOW, IT IS UNDERGOING SOUTHWESTERLY VERTICAL WIND
SHEAR OF 10 TO 15 KNOTS, WHICH IS FORECAST TO INCREASE AS THE
SYSTEM CONTINUES TO MOVE WESTWARD. OVER THE NEXT 12 TO 24 HOURS,
VERTICAL WIND SHEAR IS EXPECTED TO RAPIDLY INCREASE TOGETHER
WITH THE ENTRAINMENT OF DRY AIR. AS SUCH, THE WINDOW OF OPPORTUNITY
FOR TC 07A TO INTENSIFY IS QUICKLY CLOSING, AND THE SYSTEM IS
FORECAST TO BEGIN A WEAKENING TREND FOLLOWED BY DISSIPATION OVER
WATER BY TAU 24.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM BEING THE
SOUTHERNMOST OUTLIER, NUMERICAL MODEL TRACKERS ARE TIGHTLY
CLUSTERED OVER THE NEXT 24 HOURS, SO THERE IS HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST. ALL INTENSITY MODELS PROJECT A MAINTENANCE
OF INTENSITY OVER THE NEXT 12 HOURS, FOLLOWED BY WEAKENING BELOW
WARNING CRITERIA, SO THERE IS ALSO HIGH CONFIDENCE IN THE JTWC
INTENSITY FORECAST.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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