05 June 2020

Cristobal starts moving north, warnings issued for US Gulf coast

As expected, Cristobal spent the majority of this week sitting nearly stationary over the Yucatan Peninsula and Bay of Campeche. It briefly weakened to a Depression for a day, but is now back at tropical storm intensity. The large circulation is lopsided, with most of the "business" on the east half of the storm. The rainfall in south Mexico and parts of central America has been devastating, and now it begins its trek toward the U.S.

Rain will be a big player in the U.S. as well, and the 5-day forecast accumulations highlight Cristobal's predicted path well. Large swaths of 4"+ with localized amounts up to a foot will produce flooding in the affected areas (see map below).

It's likely to maintain tropical storm status as it heads north, and those tropical storm force winds should reach the northern Gulf coast by Saturday evening into Sunday morning.  The actual landfall (when the center crosses the coastline) is not expected until Sunday afternoon... somewhere in Louisiana most likely. Along with the new tropical storm warnings, storm surge warnings have also been issued for parts of the northern Gulf coast. Models are in really tight agreement on the track and intensity forecasts, so hopefully there are no surprises.

Of note, this is the first storm to utilize the experimental "peak storm surge" graphic that NHC has only produced in-house previously. It is part of the suite of the products available at https://www.nhc.noaa.gov/graphics_at3.shtml?start#contents. Note the maximum area in MS and eastern LA, just east of where Cristobal is expected to make landfall.

03 June 2020

Cristobal makes its first landfall in Mexico

Surface winds (white streamlines) and precipitable water (shaded background) from Wednesday morning as Cristobal made landfall in Mexico. (earth.nullschool.net)

Less than one day after becoming the earliest third named storm on record, Cristobal made landfall near Ciudad del Carmen, Mexico as a tropical storm with 60mph peak sustained winds. The rainfall has been the biggest problem in the region, with at least 20 people already killed by this storm.

Cristobal is expected to weaken now that the center is over land, but by late this week it is forecast to start moving north again and back into the Gulf of Mexico. This will allow it re-intensify and pose a threat to the northern Gulf coast late this weekend.

Track and intensity forecasts from the European model and its ensemble. The numbers along the way are hours from Tuesday evening. (UAlbany)

As of now, it does not appear likely that this will be a big wind or storm surge threat, but heavy rain is on its way to a large area later this weekend into early next week. In the outside chance that this does intensify more though, stay tuned to NHC for updates every day.

02 June 2020

Third named storm, Cristobal, forms as hurricane season begins

Tropical Storm Amanda formed in the East Pacific back on May 30, then tracked north into Guatemala where its circulation dissipated. The remnants then crossed into the Bay of Campeche on June 1 and organized into Tropical Depression 3 later on the first official day of hurricane season. Today, June 2, it has further strengthened into Tropical Storm Cristobal, the third named storm of the 2020 Atlantic hurricane season. Climatologically, the third named storm forms on August 13th, so this is about ten weeks ahead of par during a season that is expected to see above-average activity. In fact, this is the earliest formation of the third named storm on record!

Cristobal is forecast to remain nearly stationary in the Bay of Campeche for another 3-4 days before gradually drifting north across the Gulf of Mexico. Heavy rainfall will continue in southern Mexico, Belize, and Guatemala. Then the uncertainty sets in. Recent runs from the European model's ensemble favor development in the Gulf and a strong tropical storm (a hurricane is not off the table either) making landfall in the Texas-Alabama span of coastline this weekend.

The one-week cumulative rainfall forecast from the same model's deterministic run shows a wide area of high rainfall totals: 

This is clearly something that interests in the U.S. have some time to watch, but let this be a reminder to everyone in a hurricane-prone area to use this first week of hurricane season to make your preparations and plans for the coming six months.

I know I didn't write a post about Bertha one week ago, but it was a named storm for about nine hours off the coast of South Carolina... aside from the flooding rain its precursor brought to south Florida, it was fairly uneventful. After Cristobal, the next couple of names on this year's list are Dolly and Edouard.