Personal forecasts on tropical storm Cristobal

[Matt-hurricanewatcher]

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[b]The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.


Tropical depression 3
7-18-2008
8:15pm pst/11:15pm est




Winds 30 knots
Pressure 1009 millibars est
movement north 3 knots
location 31.6/79.4


The low pressure off GA has become the third depression of the 2008 season. Expected to become a tropical storm by tomarrow.

Visible and surface obs aided with radar shows that the LLC offshore Northern Florida/GA has become a depression, with the LLC becoming much better defined throughout the day. The cyclone has also formed a proto-cdo over the last few hours with some weak banding features trying to form over the southwestern quad. The LLC appears to be near 31.6/79.4, this is based on "sab" and also visible satellite placement of the inner-core of the LLC. Unoffical t number issued by "me" is 2.1t. The shear over the system is "low" near 8 knots. Not super favorable for this system to take off. Also the system will have to deal with dry air over the next 24-36 hours as it moves close to the coast.

Hurricane models show a pretty tight track with the "left" or landfall models more or less saying just inland or the "cape" or just west of Alex 2004 track, while the right models show this system moving northeastward about 100 nmi off the cape. Currently at 700-850 millibars there is a high pressure to its east, with one core to the southeast, and another to the northeast. This should keep the system moving northward or just east of north through out the next 12-24 hours.The 18z Gfdl keeps it very close to the coast, with no real development of the cyclone. While the HWRF "shows" this system unlike the Gfdl right from the start, it more or less moves it north-northeastward or northeastward along the coast with a landfall near 34.5/77 40-42 hour time frame. Gfs is south of that with a landfall near 33 north around 30-36 hours. The models are forecasting a frontal system/shortwave trough around 36-48 hours to finally start to break down the ridge to the east. If the ridge to the east stays strong this could go more north, so that would mean more northward with a landfall around 30-36 hours. The weakness is near 94 west...With this being said we will go just East of the Gfs, Gfdl and more inline with the core of the hurricane models. Those keep the system just offshore, but with a possible landfall into the cape.

We expect the system to strengthen to 50 knots by 36 hours or just before landfall. There is also a possibity that it can retain that again once back over water.

Forecast
0 30 knots 31.5/79.4
6 30 knots 31.9/79.3
12 35 knots 32.2/79.3
24 40 knots 33.1/78.9
36 50 knots 33.9/77.2-possibe landfall
48 45 knots 34.8/76.5
72 50 knots 37.5/74.5

[Matt-hurricanewatcher]

[b]The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Tropical storm Cristoball
12am pst/3am est
7-20-2008


winds 50 mph
pressure 1007 millibars
movement northeast at 8 mph
location 33.4/77.5




Cristobal moving northeastward off the SC coast..

Recon just found 51 knot flight level winds this supports 40 knots at the surface, using 850 millibars, while earlier today max flight level winds where closer to 57-58 knots at flight level or around 45-50 mph at the surface. The system has weakened some as dry air got caught into the cirulation from the mainland, that is from a caping or "stable" layer cap that doe's not allow for air to rise, now that it is night time this cap has weakened allowing the cyclone to restrengthen. Sab t shows 1.0t, this is why I don't put all in all into these numbers. It is very important to understand that "winds" can be much stronger or weaker by strength of the "LLC", not always looks of the system. But anyways on latest satellite shows the LLC far to the northwest of the deep convection. Meaning it is currently exposed. So only limited strengthing during the next 24 hours, followed by some strengthing up to 55 knots by 36 hours.

Upper level shear is becoming very very favorable with 5-6 knots of upper level shear based on cimss shear maps, with also 5-8 knots of decrease over the last 24 hours. As the system moves over the gulf stream in the next 24-36 hour time frame it could find its self in a environment quite favorable for more development. Also much less dry air to deal with. So once north of the cape we expect the cyclone to become stacked in possible at its peak around 36 hours.

The Bermuda high to the east and east-southeast of the cyclone is tilting southwest to northeast. So the system is turning more and more to the northeast. So the system should move 40-60 nmi off the NC coastline. The Gfdl keeps the system just off the cape of NC at 18-24 hours. A trough digs into the great lake region forcing the steering flow to turn south to north ahead of it, allowing the system to turn northward around 40-48 hours. It shows the system coming close to hurricane strength around 30-48 hours, with a landfall around 72 hours near 63 west. The HWRF is a good 100-120 nmi farther left of the Gfdl coming close to the United states "landfall around 54 hours. Then making landfall just east of Maine around 66 hours. For the first 24-36 hours the hurricane models are much more in agreement then they where last night, with the center remaining just off short NC, but then also turns the system northward. The kicker is as of this moment moving into the plains states of ND, SD.

Forecast
0 45 knots 33.4/77.5
6 45 knots 33.9/76.9
12 45 knots 34.5/76.6
24 50 knots 35.2 75.4
36 55 knots 37.5/71.4
48 50 knots 41.3/68.5
72 40 knots 45.6/64.5

[americanrebel]

IMHO, this is just my opinion and has no scientific proof behind it, but I think that Cristobal will get up to a 60kt system maybe 70kt at the max before heading up to Nova Scotia and causing a lot of rain up there as a TD.