[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 070241
TCDAT3

Tropical Storm Cristobal Discussion Number  22
NWS National Hurricane Center Miami FL       AL032020
1000 PM CDT Sat Jun 06 2020

Cristobal has generally changed little during the past several
hours.  The storm continues to exhibit more of a subtropical
appearance in satellite images with a broad wind field and a
limited amount of deep convection near the center.  The most
intense convection has been in a squall line that is well east of
the center near or over portions of the Florida peninsula.  Data
from both the NOAA and Air Force Hurricane Hunters support holding
the initial wind speed at 45 kt for this advisory.  The center of
Cristobal recently passed very near NOAA buoy 42001 in the central
Gulf of Mexico, which was helpful in assessing the storm's minimum
pressure.

Cristobal is moving northward at about 10 kt between a deep-layer
ridge to its east and a mid- to upper-level trough over the western
Gulf of Mexico.  This general motion should continue for about
another day, taking the center of the storm across the Louisiana
coast by Sunday night.  After the storm makes landfall, a slight
turn to the northwest is expected on Monday in response to a
mid-level ridge shifting eastward across the southeast U.S.  The
track models are in very good agreement and only small changes were
made to the previous NHC forecast.

Cristobal has about another 18-24 hours over water in which it
could strengthen.  However, given its broad structure, lack of deep
convection near the center, and dry air that is wrapping into
the west and south sides of the circulation, only a little
strengthening is predicted.  After the storm makes landfall, steady
weakening is forecast and the cyclone should weaken to a tropical
depression by late Monday.

Cristobal is a broad and asymmetric storm.  Therefore, one should
not focus on the exact forecast track, as the associated winds,
storm surge, and rainfall will extend well away 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 to begin overnight 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 from central to north Florida
overnight, spreading from east to west across the eastern and
central Gulf coast from the Florida Panhandle into Louisiana
on Sunday. This heavy rain will move into the Lower Mississippi
Valley on Monday and across the Upper Mississippi Valley and
Northern Plains into Tuesday. Significant flooding will be possible
on smaller rivers, especially where heavier rainfall occurs over
portions of the Gulf coast through the Mississippi River Valley.


FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 26.2N  90.2W   45 KT  50 MPH
 12H  07/1200Z 27.6N  90.2W   50 KT  60 MPH
 24H  08/0000Z 29.5N  90.7W   45 KT  50 MPH...INLAND
 36H  08/1200Z 31.8N  91.8W   35 KT  40 MPH...INLAND
 48H  09/0000Z 34.5N  92.8W   25 KT  30 MPH...INLAND
 60H  09/1200Z 38.3N  92.6W   25 KT  30 MPH...INLAND
 72H  10/0000Z 43.0N  91.0W   25 KT  30 MPH...POST-TROP/INLAND
 96H  11/0000Z 50.5N  86.5W   25 KT  30 MPH...POST-TROP/EXTRATROP
120H  12/0000Z...DISSIPATED

$$
Forecaster Cangialosi

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