Tropical Depression Boris Discussion Number 9
NWS National Hurricane Center Miami FL EP032020
500 AM HST Fri Jun 26 2020
Boris is showing signs of being affected by vertical wind shear,
with the strongest convection now being displaced a little to the
northeast of the center. The initial intensity remains 30 kt as a
blend of subjective estimates from TAFB and SAB and the CIMSS
satellite consensus. A combination of shear, dry mid-level air, and
marginal sea-surface temperatures is expected to produce a slow
weakening trend, with the cyclone now forecast to degenerate to a
remnant low by 48 h and dissipate completely after 72 h. The new
intensity forecast lies near the intensity consensus.
The initial motion is west-northwestward or 295/7. Boris should
move west-northwestward during the next day or so while the small
cyclone remains to the south of a low- to mid-level ridge. After
that time, the weakening cyclone is forecast to turn westward, then
west-southwestward with some increase in forward speed in the
low-level trade wind flow. The new official track forecast has
only minor adjustments from the previous forecast.
Tropical Storm Boris Discussion Number 6
NWS National Hurricane Center Miami FL EP032020
1100 AM HST Thu Jun 25 2020
Convection has increased further in association with the tropical
cyclone, with the center now under a poorly-organized band or dense
overcast. A just-received ASCAT-A overpass indicates that 35-kt
winds are occurring over an area about 40 n mi from the center in
the southeastern semicircle and based on this, the depression is
upgraded to Tropical Storm Boris.
While conditions appear to be favorable for some additional
strengthening for the next 12 h or so, none of the intensity
guidance forecasts significant intensification during that time.
Thus, the intensity forecast holds the intensity at 35 kt through 12
h. After that time, increasing vertical wind shear and dry air
entrainment should cause Boris to weaken, leading to the system
degenerating to a remnant low by 60 h and dissipating completely
after 72 h. The new intensity forecast has been adjusted downward,
but it still is a little above the intensity consensus.
The initial motion is now west-northwestward or 285/8. This motion
should continue for the next 24 h or so as Boris moves along the
south side of a low- to mid-level ridge. After that, a turn toward
the west and west-southwest is forecast as the cyclone weakens and
the low-level trade winds become the dominant steering mechanism.
The new forecast track has only minor changes from the previous
forecast, and it again lies the near consensus models.
Tropical Depression Three-E Discussion Number 1
NWS National Hurricane Center Miami FL EP032020
500 AM HST Wed Jun 24 2020
The small low pressure area well southwest of the southern tip of
the Baja California peninsula has acquired enough organized
convection near and southwest of the center to be designated a
tropical depression. Thus, advisories are being initiated on
Tropical Depression 3-E. The initial intensity is set at 30 kt in
agreement with satellite intensity estimates from TAFB and SAB.
The initial motion is 275/6. A deep-layer ridge to the north of the
cyclone is weakening as a mid- to upper-level trough develops to the
northwest and west. This evolution should cause the depression to
move northwestward between 24-72 h. After that, the cyclone should
be weakening with the low-level trade winds becoming the main
steering mechanism, resulting in a west-southwestward motion for the
balance of the forecast period. The official track forecast is near
the various consensus models.
Conditions appear favorable for strengthening for the first 36 h or
so, and the depression is expected to strengthen into a tropical
storm during that time. Beyond that time, increasing vertical wind
shear and dry air entrainment should cause a gradual weakening
trend, and most of the global models forecast dissipation near
120 h. The forecast peak intensity of 45 kt is near the upper end
of the intensity guidance, with the remainder of the forecast near
the intensity consensus.
WTPN21 PHNC 240330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
155 NM EITHER SIDE OF A LINE FROM 10.0N 131.0W TO 11.9N 136.3W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT
IMAGERY AT 040321Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.0N 131.3W. THE SYSTEM IS MOVING WESTWARD AT 06 KNOTS.
2. REMARKS: AN AREA OF CONVECTION (INVEST 93E) HAS PERSISTED NEAR
10.0N 131.3W, APPROXIMATELY 1491NM EAST-SOUTHEAST OF HILO, HAWAII.
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 260111Z SSMIS F-
18 91GHZ MICROWAVE IMAGE DEPICT A CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH BANDS OF CONVECTION WRAPPING INTO THE
CENTER FROM THE SOUTHERN PERIPHERY OF 93E. UPPER-LEVEL ANALYSIS
INDICATES THE DISTURBANCE IS IN AN AREA OF FAVORABLE VWS (< 15KTS)
AND FAIR POLEWARD AND EQUATORWARD OUTFLOW. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
250330Z.
//
NNNN
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