Tropical Storm Cristobal Nears Northern U.S. Gulf Coast

At 5:00 PM AST, the center of Tropical Storm Cristobal was located near latitude 25.2 North, longitude 90.2 West. Cristobal is moving toward the north near 12 mph (19 km/h) and this general motion is expected to continue for the next day or so, followed by a gradual turn toward the north-northwest.

On the forecast track, the center of Cristobal will move northward over the central Gulf of Mexico today and tonight, and will be near the northern Gulf of Mexico coast on Sunday. Cristobal’s center is then forecast to move inland across Louisiana late Sunday through Monday morning, and northward across Arkansas and Missouri Monday afternoon into Tuesday.

Cristobal is a large, well-organized tropical storm. Yet as expected—and in a mode very typical of early-season tropical storms in the Gulf—Cristobal is also a highly lopsided system, with most of the active weather on the storm’s east (right-hand) side. Rainbands were already pushing onto Florida’s west coast by midday Saturday, and these will spread north and west on Saturday night into Sunday.

GOES-EAST Visible Satellite Imagery showing a lopsided Tropical storm Cristobal churning in the Central Gulf of Mexico. (RAMMB/CIRA/CSU)
GOES-EAST Visible Satellite Imagery showing a lopsided Tropical storm Cristobal churning in the Central Gulf of Mexico. (RAMMB/CIRA/CSU)

Maximum sustained winds remain near 50 MPH (85 KM/H) with higher gusts. Some slow strengthening is forecast until landfall occurs on the northern Gulf coast. Weakening will begin once Cristobal moves inland late Sunday and Monday.

Tropical-storm-force winds extend outward up to 240 miles (390 km) from the center.

The estimated minimum central pressure based on data from the Air Force Hurricane Hunters is 994 millibars

This is the third named storm for the 2020 Atlantic Hurricane Season, which officially began yesterday, June 1st. Cristobal’s formation is also the third earliest formation of a named tropical cyclone in the Atlantic basin since records began.

Tropical Storm Cristobal Forecast Cone as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal Forecast Cone as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

Watches & Warnings

Tropical Storm Cristobal Storm Surge Watches and Warnings as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal Storm Surge Watches and Warnings as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

A Storm Surge Warning is in effect for:

  • The mouth of the Mississippi River to Ocean Springs Mississippi
  • Lake Borgne

A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials.

Mandatory evacuations were in effect for Grande Isle and lower Lafourche Parish, Louisiana, with voluntary evacuations increasing elsewhere in Louisiana, according to NOLA.com. See the weather.com article for more on Cristobal preparation and impacts.

A Storm Surge Watch is in effect for

  • East of Morgan City Louisiana to the mouth of the Mississippi River

A Storm Surge Watch means there is a possibility of life-threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours.

Tropical Storm Cristobal Tropical Storm Watches and Warnings as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal Tropical Storm Watches and Warnings as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

A Tropical Storm Warning is in effect for:

  • Intracoastal City Louisiana to the Okaloosa/Walton County Florida line
  • Lake Pontchartrain and Lake Maurepas

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within the next 36 hours.

Hazards Affecting Land

Tropical Storm Cristobal Key Messages as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal Key Messages as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide:

  • Mouth of the Mississippi River to Ocean Springs MS including Lake Borgne: 3-5 ft
  • Morgan City LA to Mouth of the Mississippi River: 2-4 ft
  • Ocean Springs MS to Marco Island FL including Mobile Bay, Pensacola Bay, and Tampa Bay: 1-3 ft

The deepest water will occur along the immediate coast in areas of onshore winds and will likely extend along the coast well to the east of the center. Surge-related flooding depends on the relative timing of the surge and the tidal cycle and can vary greatly over short distances.

Tropical Storm Cristobal Peak Storm Surge Graphic as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal Peak Storm Surge Graphic as of 5:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

WIND: Tropical storm conditions are expected within the Tropical Storm Warning area along the northern Gulf Coast beginning late tonight or Sunday morning.

RAINFALL: Cristobal is expected to produce total rainfall accumulations of 4 to 8 inches across the eastern and central Gulf Coast into the Lower Mississippi Valley, with isolated amounts to 12 inches. Isolated significant river flooding is possible along the central Gulf Coast. Rainfall totals of 2 to 4 inches, with local amounts to 6 inches, are expected across the Mid-Mississippi Valley. This rainfall may lead to flash flooding and widespread flooding on smaller streams across the Mid-Mississippi Valley.

Tropical Storm Cristobal 5-Day Rainfall Forecast as of 2:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center
Tropical Storm Cristobal 5-Day Rainfall Forecast as of 2:00 PM AST Saturday 6th June 2020. Credit: National Hurricane Center

TORNADOES: Isolated tornadoes will be possible this afternoon and evening across west-central Florida, and early Sunday morning along the north-central and northeast Gulf coast.

SURF: Swells generated by Cristobal will affect portions of the northern and eastern Gulf coast during the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions.

This system is of no threat to the Windward Islands, including Trinidad and Tobago.

Tropical Storm Cristobal Forecast Discussion

Cristobal continues to lack the appearance and structure of a typical tropical cyclone. In fact, the large radius of maximum wind and convective bands well removed from the center are more characteristic of a subtropical cyclone. Based on earlier Air Force Hurricane Hunter observations, the maximum winds are about 45 kt. The central pressure has held steady during the last couple of fixes of the aircraft mission, suggesting no significant strengthening since this morning. Since the system is not well organized and is likely to continue to ingest some more dry air, only a little more strengthening is expected until landfall. The official intensity forecast is unchanged and remains close to the model consensus.

The cyclone remains on track and is moving northward, or 360/10 kt. The track forecast philosophy remains unchanged. The system should continue northward between two mid-level anticyclones until it nears the northern Gulf coast. After landfall, a slight building of a ridge to the northeast should induce a turn toward the north-northwest. In 3-4 days, the post-tropical cyclone should accelerate north-northeastward ahead of a mid-tropospheric trough. Thereafter, the global models suggest that the system should merge with an extratropical cyclone near the Great Lakes. The official track forecast is in good agreement with the dynamical model consensus and is also close to the latest GFS solution.

Cristobal is likely to remain a broad and asymmetric storm when it makes landfall. Therefore, one should not focus on the exact forecast track, as the associated winds, storm surge, and rainfall will extend well away from 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 the 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.

Forecast Discussion by Forecaster Pasch from the NHC.

Facebook Comments