Above: Infrared image of Tropical Storm Cristobal at 2241Z (6:41 pm EDT) Wednesday, June 3, 2020. (NASA/MSFC Earth Science Branch)
Tropical Storm Cristobal is dousing parts of Central America with relentless rainfall as it remains parked along the southeast Mexican coast of the Bay of Campeche. As of 5 pm EDT Wednesday, Cristobal was located just inland, about 20 miles south of Ciudad del Carmen, Mexico, with top sustained winds at 50 mph. The storm was moving southeast at just 3 mph, and it should remain in this general area through at least Thursday night.
The heaviest rains around Cristobal are concentrated near its center as well as in recurring clusters across the Yucatan Peninsula, well to the east—a structure that may persist as Cristobal heads northward toward this weekend.
Massive rainfall totals piling up in Mexico and Central America
Between Cristobal and Tropical Storm Amanda, which moved into Central America from the Northeast Pacific on Sunday, rainfall totals for this week will be enormous over broad areas. Up through Wednesday morning, five-day totals in Mexico included 484.0 mm (19.06”) at Xpujil, Campeche, and 477.1 mm (18.78”) in San Joaquin, Chiapis (see map below).
Some devastating floods are possible over the next couple of days, depending on the locations of small-scale rainfall pockets associated with Cristobal and the broader Central American Gyre (CAG) that gave birth to both Cristobal and Amanda. El Salvador and southern Guatemala are especially vulnerable, even into the coming weekend, because of the flood-producing rains they received in Amanda and because southerly onshore/upslope flow will continue to plague the area.
As predicted by NHC, some potential amounts going forward from Wednesday afternoon include:
—Mexican states of Campeche, northern Chiapas, Quintana Roo, Tabasco, and Yucatan: 10 – 20 inches, isolated 25 inches
—Mexican state of southern Chiapas: 15 – 20 inches, isolated 25 inches
—Mexican states of Veracruz and Oaxaca: 5 – 10 inches
—Southern Guatemala: Additional 15 – 20 inches, isolated storm totals of 35 inches dating back to Saturday, May 30
—El Salvador: Additional 10 – 15 inches, isolated storm totals of 35 inches dating back to Saturday, May 30
—Belize and Honduras: 3 to 6 inches, isolated 10 inches
Outlook for Cristobal
Rather than taking a larger loop around the edge of the CAG, Cristobal has been staying on its north end, carrying out a tighter cyclonic loop along the southeast coast of the Bay of Campeche. The tightness of this loop over the next 24 to 36 hours will determine how far Cristobal makes it inland before increasing southerly upper-level flow begins pulling it northward, away from the CAG. Given the topography of this coastal area, we can expect some gradual weakening, but Cristobal is unlikely to dissipate unless it moves further inland than expected.
Once Cristobal embarks on its expected northward move, some restrengthening is expected. Wind shear will be mostly light to moderate (5-15 knots) until Cristobal nears the Gulf Coast, and sea surface temperatures will be around 27°C (81°F). There is only a modest amount of oceanic heat content below the surface, so intensification is unlikely to be rapid. The size of Cristobal’s circulation and the surrounding CAG also argue against fast strengthening, as larger cyclones take longer to spin up and spin down. Moreover, Cristobal will be encountering a drier atmosphere as it moves north, with mid-level relative humidity dropping from around 80% to around 60% by Sunday.
Cristobal appears most likely to reach U.S. shores as a strong tropical storm, as predicted by NHC, though a weaker storm or a Category 1 hurricane can’t be ruled out.
The consensus among model ensemble members from the 12Z Wednesday runs of both the GFS and European models is for a landfall somewhere on the east Texas or Louisiana coast between late Sunday and Monday afternoon. The GFS ensembles are more pronounced with a possible westward jog/stall near the Louisiana coast, while the Euro ensembles tend to move Cristobal more briskly inland, reaching the Midwest by Wednesday. The 12Z operational run of the Euro has a dramatic, though improbable, solution: Cristobal’s remnants team up with the approaching Northwest trough to create an intense midlatitude storm over the western Great Lakes by midweek.
Rainfall the biggest U.S. threat from Cristobal
Models and observations continue to suggest that Cristobal will be a lopsided storm in the Gulf, with impacts extending well east of where the center crosses land. Increasing surf and tides can be expected across the central and northeast Gulf Coast by Saturday, and heavy rains already reaching Florida in a slug of moisture well ahead of Cristobal may continue into the weekend. As it continues inland, Cristobal will likely bring a corridor of heavy rain with it, although its exact location remains uncertain (the forecast below from the NOAA/NWS Weather Prediction Center is a best estimate).
Soil moisture values are unusually high from eastern Oklahoma to the Carolinas, so inland flooding is a definite possibility depending on how and where Cristobal’s remnants track.
