[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 061448
TCDAT3

Tropical Storm Cristobal Discussion Number  20
NWS National Hurricane Center Miami FL       AL032020
1000 AM CDT Sat Jun 06 2020

Cristobal's satellite presentation continues to lack the appearance
of a classic tropical cyclone, with a large curved band over the
northern semicircle and little deep convection near the center.
The latest flight-level and SFMR-observed surface wind observations
from an Air Force Hurricane Hunter aircraft support a current
intensity of 45 kt.  Based on the poorly-organized state of
the system, some dry air entrainment, and interaction with an
upper-level low, only some slow strengthening is forecast, as in
the previous advisories.  The NHC intensity forecast remains in
good agreement with the model consensus.

The storm is moving northward at a slightly slower 10 kt.  There
has not been much change in the track forecast or forecast
reasoning.  Cristobal should continue northward through a weakness
in the subtropical ridge until tomorrow evening, bringing the
center to the northern Gulf coast in about 36 hours.  Later, a turn
to the north-northwest, and then back to the north is forecast as
the cyclone moves between a mid-level ridge and a trough approaching
the central United States.  In 3-4 days, the post-tropical system
should accelerate north-northeastward on the east side of the trough
and move into Canada.

Cristobal is likely to remain a broad and asymmetric storm when it
makes landfall.  Therefore, users are urged to not focus on the
exact forecast path as the associated winds, storm surge, and
rainfall will extend well to the east of the center.


Key Messages:

1. There is a danger of life-threatening storm surge outside of the
Hurricane and Storm Damage Risk Reduction System from the Mouth of
the Mississippi River to Ocean Springs, Mississippi, and a Storm
Surge Warning is in effect for those areas.  Life-threatening storm
surge remains possible in other portions of southern and
southeastern Louisiana where a Storm Surge Watch is in effect.
Residents in these locations should follow advice given by local
emergency officials.

2. Tropical storm force winds are expected by late tonight along the
northern Gulf Coast from central Louisiana to the western Florida
Panhandle, including metropolitan New Orleans, and a Tropical Storm
Warning is in effect for this area.  These winds will arrive well
in advance of and extend well east of Cristobal’s center.

3. Heavy rainfall will continue across west and north Florida today,
spreading from east to west across the eastern and central Gulf
Coast from the Florida Panhandle into Louisiana today into Sunday.
This heavy rain will move into the Lower Mississippi Valley on
Monday. Significant flooding will be possible on smaller streams,
especially where heavier rainfall occurs over portions of the Gulf
Coast and Lower Mississippi Valley.

4. Damaging and deadly flooding was already occurring in portions of
Mexico and Central America. Additional rainfall from Cristobal will
continue to slowly subside, however life-threatening flash floods
and mudslides will still be possible through today. Refer to
products from your local weather office for more information.

FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 24.2N  90.1W   45 KT  50 MPH
 12H  07/0000Z 25.6N  90.2W   45 KT  50 MPH
 24H  07/1200Z 27.4N  90.2W   50 KT  60 MPH
 36H  08/0000Z 29.3N  90.7W   50 KT  60 MPH...ON THE COAST
 48H  08/1200Z 31.5N  91.5W   35 KT  40 MPH...INLAND
 60H  09/0000Z 34.5N  92.5W   25 KT  30 MPH...INLAND
 72H  09/1200Z 38.0N  92.3W   20 KT  25 MPH...POST-TROP/INLAND
 96H  10/1200Z 47.5N  86.0W   20 KT  25 MPH...POST-TROP/EXTRATROP
120H  11/1200Z...MERGED WITH EXTRATROPICAL LOW

$$
Forecaster Pasch

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