Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
ह्रस्वः स्निग्धः सुप्रसन्नः श्वेतकेतुः सुवृष्टिकृत् ।क्षिप्रादस्तमयं याति दीर्घकेतुरवृष्टिकृत् ॥ ९७ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 97.
A short, smooth, clear white comet that sets soon brings good rain. A long comet brings no rain.
Simple meaning: A short, bright white comet that soon fades brings good rain. A long one brings drought.
अनिष्टदो धूमकेतुः शक्रचापसमप्रभः ।
The smoke comet is bad and can bring harm to a kingdom.
मणिहारस्तुवर्णाभा दीप्तिमंतोऽर्कसूनवः ।
Bright gold-like comets born of the Sun, seen in the east or west, can bring loss to kings.
वंसुकबिंबक्षितिजच्छुकतुंडादिसन्निभाः ।
Red comets like flowers, fruit, blood or a parrot's beak are born of fire and give results.